Minecraft Error: org.lwjgl.LWJGLException: Pixel format not accelerated

Minecraft gives me this message in the crash report:  ---- Minecraft Crash Report ---- // Sorry :(  Time: 23/1/15 8:28 PM Description: Initializing game  org.lwjgl.LWJGLException: Pixel format not accelerated     at org.lwjgl.opengl.WindowsPeerInfo.nChoosePixelFormat(Native Method)     at org.lwjgl.opengl.WindowsPeerInfo.choosePixelFormat(WindowsPeerInfo.java:52)     at org.lwjgl.opengl.WindowsDisplay.createWindow(WindowsDisplay.java:252)     at org.lwjgl.opengl.Display.createWindow(Display.java:306)     at org.lwjgl.opengl.Display.create(Display.java:848)     at org.lwjgl.opengl.Display.create(Display.java:757)     at org.lwjgl.opengl.Display.create(Display.java:739)     at bss.an(SourceFile:526)     at bss.ak(SourceFile:355)     at bss.a(SourceFile:302)     at net.minecraft.client.main.Main.main(SourceFile:124)   A detailed walkthrough of the error, its code path and all known details is as follows: ---------------------------------------------------------------------------------------  -- Head -- Stacktrace:     at org.lwjgl.opengl.WindowsPeerInfo.nChoosePixelFormat(Native Method)     at org.lwjgl.opengl.WindowsPeerInfo.choosePixelFormat(WindowsPeerInfo.java:52)     at org.lwjgl.opengl.WindowsDisplay.createWindow(WindowsDisplay.java:252)     at org.lwjgl.opengl.Display.createWindow(Display.java:306)     at org.lwjgl.opengl.Display.create(Display.java:848)     at org.lwjgl.opengl.Display.create(Display.java:757)     at org.lwjgl.opengl.Display.create(Display.java:739)     at bss.an(SourceFile:526)     at bss.ak(SourceFile:355)  -- Initialization -- Details: Stacktrace:     at bss.a(SourceFile:302)     at net.minecraft.client.main.Main.main(SourceFile:124)  -- System Details -- Details:     Minecraft Version: 1.8.1     Operating System: Windows 7 (x86) version 6.1     Java Version: 1.8.0_31, Oracle Corporation     Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation     Memory: 52381136 bytes (49 MB) / 101867520 bytes (97 MB) up to 518979584 bytes (494 MB)     JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M     IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0     Launched Version: 1.8.1     LWJGL: 2.9.1     OpenGL: ~~ERROR~~ RuntimeException: No OpenGL context found in the current thread.     GL Caps:      Using VBOs: No     Is Modded: Probably not. Jar signature remains and client brand is untouched.     Type: Client (map_client.txt)     Resource Packs: []     Current Language: ~~ERROR~~ NullPointerException: null     Profiler Position: N/A (disabled)


This really caught my attention. As you can below this photo, there's user (Maybe a  person or maybe bot) answered the question but it is not answer the question.     So is this person just a pure troll or a bot want to test us if we have really watch carefully those question and answer?


I would like to access root-folder with Thunar but the system won't let me, even if I have setup a root in a terminal window.   What's the way to access the root-folder (with write access) in Thunar (GUI)? Does it work out of the box without installation of additionals?  I need to add drivers for a USB 3.0 PCIe card and the files have to be placed in the target kernel (e.g. \linux-2.6.28)  The answers to this topic I read at askubuntu.com require some other apps to be installed, like Nautilus or gksu, which are not present at my Ubuntu Studio 15 installation and I don't want them to install.   I've been able to define a root user's password and operate as root in a terminal window, but this won't let me access root-directory with Thunar.


Show that $E=\{(x,\alpha)\mid 0\leq \alpha<|f(x)|\}$ is measurable if $f$ is measurable.

I have to show that $E=\{(x,\alpha)\mid  0\leq \alpha<|f(x)|\}$ is measurable if $f$ is measurable.   My attempt :  If $f=\boldsymbol 1_F$ where $f$ is measurable, then $$E=\big((\mathbb R\cap F)\times [0,1[\big)\cup \big((\mathbb R\cap F^c)\times \{0\}\big)$$ which is measurable since it's intersection, union and product of measurable set. If $f$ is simple (remark that $f$ simple $\iff$ $|f|$ simple) i.e. $$|f|=\sum_{i=1}^n a_i\boldsymbol 1_{F_i}$$ where $a_i>0$ and $F_i$ measurable, we obtain in the same way $$E=\bigcup_{i=1}^n\big((\mathbb R\cap F_i)\times [0,a_i[\big)\cup \bigcap_{i=1}^n \big((\mathbb R \cap F_i^c)\times \{0\}\big)$$ which is also measurable since it's finite union, intersection and product of measurable set. Finally, if $|f|\geq 0$ we have a sequence of simple function $\{\varphi_k\}_{k\in\mathbb N}$ s.t. $$\varphi_k(x)\nearrow |f(x)|\quad\text{ for all }x.$$  Let $$E_n=\{(x,\alpha)\mid 0\leq \alpha\leq \varphi_n(x)\}.$$ Therefore $E_n\subset E_{n+1}$ and thus $E_n\nearrow E$ i.e. $$E=\bigcup_{n=1}^\infty  E_n,$$ and since $E_n$ is measurable, the set $E$ is measurable.  Is it correct ?


Which of the following inequalities hold for a ring $R$ and an ideal  $I\subset R$?  $\operatorname{height}I\leq\dim R-\dim R/I$ $\operatorname{height}I\geq\dim R-\dim R/I$


When I run sudo apt update I get the following error: Hit:1 http://in.archive.ubuntu.com/ubuntu focal InRelease Hit:2 http://in.archive.ubuntu.com/ubuntu focal-updates InRelease                Hit:3 http://in.archive.ubuntu.com/ubuntu focal-backports InRelease              Hit:4 http://dl.google.com/linux/chrome/deb stable InRelease                        Hit:5 http://in.archive.ubuntu.com/ubuntu focal-security InRelease                  Hit:6 http://in.archive.ubuntu.com/ubuntu focal-proposed InRelease                  Hit:7 http://ppa.launchpad.net/kivy-team/kivy-daily/ubuntu focal InRelease          Hit:8 http://ppa.launchpad.net/kivy-team/kivy/ubuntu focal InRelease Ign:9 http://ppa.launchpad.net/webupd8team/java/ubuntu focal InRelease Err:10 http://ppa.launchpad.net/webupd8team/java/ubuntu focal Release   404  Not Found [IP: 2001:67c:1560:8008::15 80] Reading package lists... Done E: The repository 'http://ppa.launchpad.net/webupd8team/java/ubuntu focal Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.  How to fix this and update !!!


How do I UV unwrap and texture onion-like object?

What would be the best method to UV unwrap and texture an onion-like object?   It doesn't have to be an onion specifically, it's just an example. I'm talking about all the objects that are spherical in shape and have distinctive parallel lines following the surface from one pole to the opposite pole, converging around both poles (like watemelons etc.).  I'm mostly interested with image-based texture solutions, not procedural ones.  The photo is Creative Commons licensed image taken by flickr.com/photos/user-colin/


Identify a window that pops in for less than a second

I am using Windows 10. For a few days now, this keeps happening, even after a few restarts.  There is a window, slightly larger than the default size of cmd, that appears for less than a second, about once every hour. It shows up, but doesn't stay long enough for a name to appear (even if it did, I wouldn't have the time to read it), or for any content (except for the white background) to show up.  This reminds me a lot of C# Console programs lacking any sort of Console.ReadLine() or Console.ReadKey(), that show up and disappear instantly when debugging.  I can't find anything out of the ordinary in the processes (including background and "show processes for all users".  The window is mostly annoying because it takes away my current focus, because as would most pop-ups do, it seems to take focus when appearing, then I have to refocus in what I was doing. This is particularly annoying in some games, like Starcraft II, where the pop-ups forces me out of the game, and I have to alt-tab back in, and that can hurt a match a lot if the timing is bad.  I'm looking for a way to identify which program is creating this window (maybe it's a virus, maybe it's just a bug in something on my computer), in the hopes of figuring out how to stop it.


strange characters in wordpress website displayed for visitors

Apparently a lot of people complain that they only see random letters and characters:    My biggest problem is that I can't reproduce the problem on ANY of my devices! Not on my Windows XP laptop, not on my Windows 7 laptop, not on my Android phone or my iPod Touch. It doesn't matter which browser I'm using. The only time I see the problem myself is when I try to share one of my blog posts on Google+, because the blog description then appears in strange characters.  So, first of all I need to find a way to reproduce the problem somehow. Otherwise I won't be able to see if what I did fixed the problem or not.  I did everything that @toscho recommended, but nothing helped.  Did anybody ever run into a similar problem or would you know where I could start to look for the problem?  Edit: I contacted my webhost. They couldn't reproduce the problem, just like me. They said that they have enabled gzip compression on their servers. They suggested turning off one plugin after another to see what happens, but as I can't reproduce the problem, I can't do that. Please help!  More and more readers are complaining about this problem. Most of them just need to refresh the page or wait a few minutes and then the site loads normally, but I'm still using a lot of traffic because of that.  EDIT 2: The W3 Total Cache Plugin FAQ says: I see garbage characters instead of the normal web site, what's going on here?  If a theme or it's files use the call php_flush() or function flush() that will interfere with the plugins normal operation; making the plugin send cached files before essential operations have finished. The flush() call is no longer necessary and should be removed.  I am pretty sure that none of my code has this call anywhere, but I'm not 100% sure. Is there any way to find out other than searching through millions of characters in all of my files?


How to copy files from one machine to another using ssh

I'm using Linux (centos) machine, I already connected to the other system using ssh. Now my question is how can I copy files from one system to another system?  Suppose, in my environment, I have two system like System A and System B. I'm using System A machine and some other using System B machine.  How can I copy a file from System B to System A? And, copy a file from System A to System B?


Currently, to approve or reject an application, user need to click this highlighted button from image (1), then it will redirect user to page image (2). User need to click highlighted text to go to approval page image (3). Button from image (1) is not a standard page. It is URL. Highlighted text from image (2) is from flows, and page image (3) is a approval process. What I want is, once user click on highlighted button from page image (1), it will bring user to page image (3). May I know how to do that?


Import/Load geometries in predefined bounding box

I would like to load geometries in any format into a predefined box and take pictures around that box. How can I make sure that the object I am importing is scaled in an appropriate manner? Side note: I am trying to force the scaling as the camera is always focused on the cube which ensures the object is always captured appropriately.


What is translation invariance in computer vision and convolutional neural network?

I don't have computer vision background, yet when I read some image processing  and convolutional neural networks related articles and papers, I constantly face the term, translation invariance, or translation invariant. Or I read alot that the convolution operation provides translation invariance?!! what does this mean? I myself always translated it to myself as if it means if we change an image in any shape, the actual concept of the image doesn't change. For example if I rotate an image of a lets say tree, it's again a tree no matter what I do to that picture. And I myself consider all operations that can happen to an image and transform it in a way (crop it, resize it, gray-scale it,color it etc...) to be this way. I have no idea  if this is true so I would be grateful if anyone could explain this to me .


\documentclass[11pt,a4paper]{article}     \usepackage[T1]{fontenc}     \usepackage{lipsum}     \usepackage{tocloft}     \begin{document}      \tableofcontents     \thispagestyle{empty}         \newpage      \section{Preface} %want section number to be 0     \thispagestyle{empty}         \pagenumbering{roman}     \lipsum[1-3]     \newpage      \section{Start From Here}     \lipsum[1-5]      \section{And So On...}     \lipsum[1-5]     \end{document}      How do I get section numbering to start at 0?   Edit: I know I can do \section*{Preface}, but that removes it from the ToC, which isn't what I want.


How to achieve nomenclature entries like: symbol, Description, Dimension and unit, etc?

The title is pretty much I want to ask. More detail, the nomenclature entries should be sorted in groups like:   Nomenclature     Acronyms     Symbol  Description     % no Dimensions and Units      ...     Greek Symbols     Symbol  Description             Dimensions     Units     ...     Roman Symbols     Symbol  Description             Dimensions     Units     S       Surface area vector     L^2            m^2     ...    Superscripts     Symbol  Description     % no Dimensions and Units      ...    Dimensionless Numbers     Symbol  Description     Definition     ...   e.g. expected entries like this:       My current nomenclature settings for grouping [book class]:  %---------------------------------------------------------- %                        Nomenclature %---------------------------------------------------------- %\renewcommand{\nomname}{List of Symbols and Abbrev.} \renewcommand\nomgroup[1]{%   \ifthenelse{\equal{#1}{A}}{%    \item[\textbf{Acronyms}] }{%                  A - Acronyms     \ifthenelse{\equal{#1}{R}}{%      \item[\textbf{Roman Symbols}]}{%            R - Roman       \ifthenelse{\equal{#1}{G}}{%         \item[\textbf{•} Symbols }]}{%          G - Greek           \ifthenelse{\equal{#1}{S}}{%            \item[\textbf{Superscripts  }]}{{%          S - Superscripts         \ifthenelse{\equal{#1}{U}}{%          \item[\textbf{Subscripts }]}{{%                 U - Subscripts         \ifthenelse{\equal{#1}{X}}{%          \item[\textbf{Other Symbols }]}%            X - Other Symbols                     {{}}}}}}}}}} %\ifpdf \renewcommand{\nomlabel}[1]{\hspace{1 em}#1}%{\hspace{1.5 em}#1} \renewcommand*{\nompreamble}{\markboth{\nomname}{\nomname}}   But how to extend it with Dimensions and Units?


Ubuntu 20.04 Lenovo Ideapad Microphone not working

Internal Microphone is only recording static noise on Lenovo Ideapad and Ubuntu 20.04. I've tried deleting PulseAudio config, restarting PulseAudio, and reinstalling Alsa. sudo pavucontrol was no help either.  I know the mic is fine since it works on another OS.   This is the Alsa config:  pouria@pouria-pc:~$ sudo cat /etc/modprobe.d/alsa-base.conf  # autoloader aliases install sound-slot-0 /sbin/modprobe snd-card-0 install sound-slot-1 /sbin/modprobe snd-card-1 install sound-slot-2 /sbin/modprobe snd-card-2 install sound-slot-3 /sbin/modprobe snd-card-3 install sound-slot-4 /sbin/modprobe snd-card-4 install sound-slot-5 /sbin/modprobe snd-card-5 install sound-slot-6 /sbin/modprobe snd-card-6 install sound-slot-7 /sbin/modprobe snd-card-7  # Cause optional modules to be loaded above generic modules install snd /sbin/modprobe --ignore-install snd $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-ioctl32 ; /sbin/modprobe --quiet --use-blacklist snd-seq ; } # # Workaround at bug #499695 (reverted in Ubuntu see LP #319505) install snd-pcm /sbin/modprobe --ignore-install snd-pcm $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-pcm-oss ; : ; } install snd-mixer /sbin/modprobe --ignore-install snd-mixer $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-mixer-oss ; : ; } install snd-seq /sbin/modprobe --ignore-install snd-seq $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-seq-midi ; /sbin/modprobe --quiet --use-blacklist snd-seq-oss ; : ; } # install snd-rawmidi /sbin/modprobe --ignore-install snd-rawmidi $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-seq-midi ; : ; } # Cause optional modules to be loaded above sound card driver modules install snd-emu10k1 /sbin/modprobe --ignore-install snd-emu10k1 $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-emu10k1-synth ; } install snd-via82xx /sbin/modprobe --ignore-install snd-via82xx $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-seq ; }  # Load saa7134-alsa instead of saa7134 (which gets dragged in by it anyway) install saa7134 /sbin/modprobe --ignore-install saa7134 $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist saa7134-alsa ; : ; } # Prevent abnormal drivers from grabbing index 0 options bt87x index=-2 options cx88_alsa index=-2 options saa7134-alsa index=-2 options snd-atiixp-modem index=-2 options snd-intel8x0m index=-2 options snd-via82xx-modem index=-2 options snd-usb-audio index=-2 options snd-usb-caiaq index=-2 options snd-usb-ua101 index=-2 options snd-usb-us122l index=-2 options snd-usb-usx2y index=-2 # Ubuntu #62691, enable MPU for snd-cmipci options snd-cmipci mpu_port=0x330 fm_port=0x388 # Keep snd-pcsp from being loaded as first soundcard options snd-pcsp index=-2 # Keep snd-usb-audio from beeing loaded as first soundcard options snd-usb-audio index=-2   This is my hardware:  pouria@pouria-pc:~$ sudo lspci -knn | grep Audio -A3 00:1f.3 Audio device [0403]: Intel Corporation Sunrise Point-LP HD Audio [8086:9d71] (rev 21)     Subsystem: Lenovo Sunrise Point-LP HD Audio [17aa:380d]     Kernel driver in use: snd_hda_intel     Kernel modules: snd_hda_intel 00:1f.4 SMBus [0c05]: Intel Corporation Sunrise Point-LP SMBus [8086:9d23] (rev 21)   I just upgraded my kernel but didn't have any effect  pouria@pouria-pc:~$ uname -r 5.7.0-050700-generic   UPDATE:  I asked the question  with no details (nor bounties), surprisingly some guy answered that gave me a clue.  In vokoscreen if I set the recording option to Pulse it doesn't record anything but when the recording option is set to Alsa it recrods.  So now I know Alsa is fine but PulseAudio is messing it up. Now please help me with PulseAudio.


Why Do 240V Circuits Not Require Neutral?

Someone told me that a 240V circuit does not require a neutral wire in the cable.  Can anyone explain this phenomenon from the electricity perspective and generally explain why circuits do and do not need a neutral wire?


How to convert a shapefile into OSM .PBF format

I have a large .gdbtable file (1.3 GB) with a road network that I would like to convert to .PBF format keeping the topology information.   I can load the .gdbtable file in QGIS so I thought it should be straightforward to write/export the file in .PBF but I cannot find this option. I would rather use QGIS to do this but an ArcGIS solution would be welcomed as well.  Any ideas on how to do this?


For an arbitrary $x_{0}$ in $\left(\, 0,\pi\,\right)$ we define $x_{n + 1}=\sin\left(\, x_{n}\,\right)$.  Using the limit of the sequence as $n$ tends to infinity we're supposed to find the limit of $\,\sqrt{\,n\,}\,\sin\left(\,x_{n}\,\right)$  .   I literally don't know where to start, any ideas ?.


Symbolic coordinates for a hyperbolic grid?

Rephrasing     (one year later)    (original question is below)   Apparently the original question wasn't clear, or nobody knows an answer (or both).  So I will try to rephrase it.   Look at your favorite .  This question asks for a labeling system for the points.  Of course we could draw the grid on the Poincare disk, and use real numbers (the (x,y) coordinates of each point), but in practice that would raise all sorts of precision issues that could surely be avoided if one had a proper symbolic coordinate system.  You shouldn't need real numbers if you're staying on grid points!  Just like (2,3)+(0,1) is trivial to do by hand (or in your head) for the square grid, we'd like some form of symbolic coordinates (i.e. consisting of finite sequences of symbols) for a hyperbolic grid, in which simple operations on small grid vectors are similarly easy.  If you take some sequence of left and right turns in a hyperbolic grid city, what should you keep track of in your head so you can take the optimal route back to your starting point?  In a Euclidean square grid, it is {(int)X, (int)Y, (enum)direction you are facing}, and we all know how to use this.  Is there any hyperbolic grid where this question has a nice answer?    Original Question  If we consider the Euclidean plane, then a square grid works well with using two integers (the coordinates) as a representation for vectors that lie on the grid.  Does anybody know of a similarly nice representation for working in the hyperbolic plane?  Desirable features of any such system:  $-$ It should be easy to add two vectors.  $-$ It should be easy to see if two vectors are the same.  $-$ It should be easy to see if two vectors are close.  $-$ It should be easy to rotate a vector by an angle that is a symmetry of the grid.  $-$ Every point in the plane should be near some vector. (The grid shouldn't have large empty regions.)   Note that "addition" using continuous coordinates would most naturally be defined in terms of parallel transport, and it is neither commutative nor associative.  On a grid, however, the issue of orientation needs to be addressed differently, since parallel transport along arbitrary grid vectors will introduce rotations that are not a symmetry of the grid, so to remain on the grid, addition will need to be defined using something other than parallel transport.  Since hyperbolic grids have an exponential number of points (as a function of distance from the origin), our symbolic coordinates will need to have a length proportional to the length of the vector.  Don Hatch has a web page which gives some .  ("Easy" means an efficient algorithm that is doable by hand, like how the algorithms for addition and subtraction using the standard digit-sequence representation of integers can be used for the Euclidean square grid. Using hyperbolic functions of real numbers, always keeping track of enough digits to identify the nearest grid point, does not count as easy!)    Addendum: Many readers seem to be disturbed by a little voice saying "But vectors don't make sense in the hyperbolic plane!": What that voice is really saying is that the hyperbolic plane doesn't give you all the nice properties you are used to in Euclidean space or in vector spaces.  So if you define vectors as objects having specific properties you are used to (such as having a direction that is unaffected by parallel transport), then that definition may not correspond to anything in the hyperbolic world.  You could use the term isometry, but that is typically a fixed mapping from the space to itself, and in the hyperbolic plane the isometry corresponding to a vector would depend on the starting point. (However, isometries will be central to any solution, I assume.) And a geodesic is a fixed path within the space, no different from a hyperbolic line or segment.  The paper  offers one solution.  offer another.  I deliberately leave them undefined in this question, as I am looking for any workable system.


Should I compare CPUs based purely on advertised speed?

There are many types of CPUs, like Pentium, Atom, core 2 duo, core iX (X = 3,5, ....), But I always don't look at them this way! I always look at their speed which in GHZ unit and then compare them with each other. For example when some CPU is in type of 'X' with 2 GHZ of speed and another one is in type of 'Y' with 2.2 GHZ of speed, I say the second one ('Y') has better speed and also better performance.  Is it a correct way?


Hi，I have created a model. I want to adjust the dimension of the model.  Scale was 0.136, 0.136, 0.136 and Dimensions was 1.73164, 1.62762, 2.33337. When I change the size of Diomension in x-achse, the number of x-achse in Scale will be automatic changed. But I just want to change the Dimension and keep the number in Scale not be changed. what should I do？


IMO 2019: Find all functions $f: \mathbb Z \to \mathbb Z$ such that $f(2a) + 2\, f(b) = f \big( f (a+b)\big)$.

Source: International Mathematical Olympiads, 2019.   The question is:      Let $\mathbb{Z}$ be the set of integers. Find all functions  $f: \mathbb Z \to \mathbb Z$ such that, for all integers $a$ and $b$, the following is true    $$f(2a) + 2\,f(b) = f\big(f (a+b)\big)\,.$$   I only managed to do this:   Suppose some function f has the form : f(x)= n.x ( with n, integer).   We would get :   n(2a)+ 2(nb) = n(n(a+b))  --> 2na + 2nb = n²(a+b)   --> 2n (a+b)  = n²(a+b)    ( Dividing by a + b, provided a+b is not equal to 0)   --> 2 n = n²   --> n² = 2 n   --> n = 2.    ( Although I wonder whether dividing by number n is legal, even if n is not 0)   So, apparently, if a function satisfying the f-conditions has form f(x)= n.x, then   this function must have form f(x) = 2x.   However, apparently, f must have any sum ( a + b) in its domain, in order to be from Z to Z; for the expression f( a+b) featured in the expression defining f.  But, while solving the equation, I excluded the case in which (a+b)= O. Notwithsatnding (0 + 0) is a sum of integers.   So, my hypothesis fails, and I am left with a negative conclusion :   there is no function f ( satisfying the f formula)  such that f(x) = n.x.


Spontaneous symmetry breaking of a spinor / vector field

Why does SSB deal only with scalar fields and not with fermion or vector fields?  My professor told me that it's closely related to the Lorentz invariance of the theory, but I don't understand at all the meaning of that.


Encryption/Decryption invalid parameters using DES algorithm

I am currently working on a Encryption/Decryption exercise. Main functionality is done however it was done in console. Now I will create the application in win form.  My Encryption/Decryption methods take byte arrays as arguments. I used DES as per program specifications. I was population the byte arrays like this   //were mk is a string byte[] mkBytes = System.Text.UTF8Encoding.UTF8.GetBytes(mk);    However CreateDecryptor method was giving "Specified key is not a valid size for this algorithm" error.  Therefore to go around the problem I was forced to do this, hard code the whole bit array and worked fine.  byte[] masterKey_bytearr = { 0x12, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x23 };   But now I face the problem again since the user will be inputting the string in a textbox and cannot hard code them myself.  How can I get the string from textbox and assign it to a byte[] suitable for DES CreateDecryptor method?


How to combine two SPF (TXT) records when one is from a local mail server?

I would like to add a second SPF TXT record to my domain, allowing an external mail-server to send emails from my domain so it won't be classified as spam on the receiving end. I've read that I should not create two separate TXT records, but combine them into one.  There's currently a mail-server running on my domain as well, and it has this TXT record:  v=spf1 +a +mx -all  The one that I have to add to allow the external server is:  v=spf1 a mx include:spf.externaldomain.com ~all  I've found related questions on how to combine two records with two include:'s, but as my existing record has a +a +mx and -all, and the second one a mx and ~all, I'm not sure how to combine them. Obviously, I still want the record for my mail-server on my domain give the correct SPF replies as well.


Access Denied when Reading/Writing to Program FIles

I have a small program that is installed in a custom folder in the program files, but when I tried to read or write to files that are needed to operate, the program raises an Access Denied Exeption. How can I elevte the program, with the user's permission of course.


How do I move my own question to another Stack Exchange site?

I've posted a question to  on Google Spreadsheets that I would like to move to .  I think adding a function for moving the question to another Stack Exchange site (for the user who wrote the question) could be useful.  As , a user with 250 reputation  could ask other users to vote to move his own question to another Stack Exchange site, so why not just let the user move his own question?  Since users with 3000 reputation can move any question to any Stack Exchange site, experienced users can fix any inappropriate moves by inexperienced users, avoiding the delay of a vote.


Separating a shapefile into separate shapefile based upon their features using a python script

I have a shapefile of a US. I need to make an individual shapefile for all the states in the US using a python in ArcGIS. How can I do it?


Can't log in to Pokemon Go with Google Account on my New Phone? Not an Option!

Upgraded from S4 to S7 Galaxy. Signed out of Pokémon Go on the S4. Downloaded Pokémon Go on S7 and I do not get the option to log in with my Google account. Only option is Pokémon Trainer Club. How can I get to a Google login on the new S7?


Question: Prior to a meeting of 20 people, a file was prepared for each person with their names written. The person who comes first to the meeting picks a random file without looking at the names. Those who came later look for their own file. If their files were not taken by someone else, then they pick their own file. Else, they pick a random file. What is the probability of the last person in the meeting getting his or her own file?  It seems a bit tricky. I tried to solve directly by using conditional probability but failed since the cases are confusing.


How to give Onclick function to dynamic created button (Number of button will change every time)

I am creating number of buttons depending upon length of records . So number of buttons will change when record will change every time I will run program. Here is my code of it .  for (var i = 0; i < labels.length; i++) { <button type="button" id='+i+'>'+i+'</button>'; }   It will create buttons 1,2,3,4,5....up-to length of labels. Now problem is that I want to assign them id and onclick. On everyonclick It will pass value to a function which button was press like I will pass 1 if 1st button was pressed and 2 if 2nd button is pressed. How I can do it ? I saw that  question but he is using jquery and not passing any values to new function based on Id (which is my main problem) .


I had joined the quite a lot of beta websites under Stack Exchange (,  to name a few).  Out of sheer curiosity, I would like to know and understand if the websites are categorized as beta based on the number of questions asked there? I couldn't help but notice most of them have an average of only a few thousand questions. Will they be pulled down if the activity remain considerably low?


I see bold and italics button but no inline code while it uses quite an uncommon syntax (back ticks, `` - the syntax is good, just not very obvious). It would be convenient to have this button.  Related but not the same:


The  is at best quite lame.  I think it would be easier to ask better questions , like in a standard email client.  One draft isn't enough.


Knife Tool is stuck to the origin of the geometry of the object

The Knife tool is stuck to the origin of the object. I hover all over the vertices and edges, and nothing. There is nothing inside of that object, no hidden vertex, it's literally the origin. I tried it on all of my objects in the file, and they all have the same problem, but when I open a new file, the Knife Tool works just fine. I can't find the answer anywhere else, so the only way to continue is to copy paste everything I have in that Blender file to a new one in order for it to work again.  System Information  Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 457.30  I am using Blender Version 2.91


Which one is correct?   statistical models for process monitoring Statistical models for processes monitoring.


Please tutor the usage of patchcmd and xpatch

I understand that the  package provides a command \patchcommand that can be used to add material at the beginning and/or end of the replacement text of an existing macro. It works for macros with any number of normal arguments but has limitations for macros with optional arguments.   was introduced to take care of the above limitations as well as provide some additional functionality.   Now, when I try to comprehend the usage of the above packages by reading the user documentations (, ), I get the feeling that they move to implementation details a little too quickly compared to other package documentations. There are not enough explanations or examples.  I also tried to grasp the concepts by reading the  and more or less understood whatever is presented there. However, that is not enough.  So, do you think we can ask for a complete tutorial on the usage of patchcmd and xpatch? Explaining the usage of the relevant commands like \patchcmd, \pretocmd and \apptocmd as well as, \xpatchcmd, \xpretocmd and \xapptocmd with sufficient examples should suffice.


Prove or disprove: If $a>b$ and $\gcd(a,b)=1$ then $\gcd(a,a-b)=1$

Let $a,b\in\Bbb{N}$. Prove or disprove that if $a>b$ and $\gcd(a,b)=1$ then $\gcd(a,a-b)=1$.     I think it is true.  Proof If $\gcd(a,b)=1$ then $as+bt=1$ for some $s,t\in\Bbb{Z}$. Then $as+(b+a-a)t=as+(b-a)t+at=a(s+t)+(b-a)t=am+(a-b)k=1$, where $m=s+t\in\Bbb{Z}$ and $k=-t\in\Bbb{Z}$. Hence again by Bézout's identity, we conclude $\gcd(a,a-b)=1$. $\square$  Is it correct?


How prove that $\lim\limits_{x\to+\infty}f(x)=\lim\limits_{x\to+\infty}f'(x)=0$ if $\lim\limits_{x\to+\infty}([f'(x)]^2+f^3(x))=0$?

Question:     Let $f$ be differentiable on $[0,+\infty)$, such as$$\lim_{x\to+\infty}\left([f'(x)]^2+f^3(x)\right)=0$$show that $$\lim_{x\to\infty}f(x)=\lim_{x\to\infty}f'(x)=0$$   I think this problem is similar to  and (the  background)  For my problem I guess that if  $$\lim_{x\to+\infty}\left([f'(x)]^{2m}+f^{2n+1}(x)\right)=0,m,n\in N^{+},n,m>1$$ then we have $\lim_{x\to\infty}f(x)=\lim_{x\to\infty}f'(x)=0$.


Miktex generated a PDF file with dimensions 8.27 x 11.69 inches. Is there any way to "fix" it to 8.5 x 11 inches, the US Letter default printing size?


A vector bundle is said to be flat if it is endowed with an linear connection with vanishing curvature, ie. a flat connection.  Is the tangent bundle $TS^2$ of a $S^2$ flat? My question  is also about how do we know if our bundle is flat or not? What are the obstacles to this?    Let we have a flat connection $\nabla$. This is equivalent to the fact that we have a parallel transport $P_{\gamma (t)}$. Fundamental group $\pi_1 (S^2) = 0$. Then parallel transport is path-independent (because connection is flat). We can take an arbitrary vector $X \in T_pS^2$ and spread it around the manifold by the parallel transport. Thus, we obtain a non-trivial nondegenerate global vector field $X(q)$, where $q \in M$. But this contradicts the Hairy ball theorem.  Is my reasoning correct?


Do you forfeit tax refunds/credits if you aren't required to and don't file by April 15?

Some people in the United States are not required to file an income tax return (e.g. their income is too low).  However, they could be entitled to a refund of wages withheld, or a credit such as the Earned Income tax credit.  They need to file a return in order to get the refund or credit.  If such a person does not file by April 15, do they forfeit their refund/credit?


Is it bad to pass a column name as a parameter in a query, based on user input?

Many references like W3schools and Wikipedia state "If the original statement template is not derived from external input, SQL injection cannot occur".   What does this mean exactly? I've tried to search more on the subject but most references leave it at exactly that.   To be more specific, I am talking about:  If the original statement template is not derived from external input  As, I've researched as to why it cannot occur.   Does this mean, as long as you don't directly put the user input into the query, like:  SELECT * FROM pubs WHERE " . $_POST['extra'] . " LIKE '%Yes%'   as opposed to:   SELECT * FROM pubs WHERE ? LIKE ?   Also, is it okay to pass a column name as a parameter like i've done above. For instance say I have   $extra = $_POST['extra']; $yes = "%Yes%";   and then I prepare:   $stmt = $mysqli->prepare(SELECT * FROM pubs WHERE ? LIKE ?);   and then bind:  $stmt->bind_param("ss", $extra, $yes);   Is this safe an correct?


What to do when we can't login to the superuser

While trying to create a new  file in php I granted ownership permission to www-data. There onwards I can't login to the superuser session but I can login to the guest session. The login screen asks for password and on typing password thereafter it redisplays the screen. What to do?


I'm reading some Sherlock Holmes stories (don't judge - it's good vacation reading) and Conan Doyle has Holmes saying things like "Sorry to knock you up, Watson..." which I'm finding very... odd.  From the context I'm gathering that it means "wake up," but my head immediately goes to the modern American meaning of "impregnate."  Is "knock up" ever used with this meaning anymore?  And if not, did it disappear around the time that the pregnancy meaning became common, or did it vanish on its own?


As a picture often speaks better than words, here are the two images of my problem. I'm trying to get a smooth render on this object. I tried many options but no way I always have these artifacts. Is it possible to have a smooth rendering with a convex surface?     Here what I'm trying to model


I need to connect to remote DB over Hamachi, the tutorial states that I need to set tcp/ip to enable (which I did, in SQL Server Configuration Management tool) and add Hamachi IP to ipadresses, but which one? ip4,ip6...


In fact the real question is: Does $\lim\limits_{n\to\infty}1^{n}=e$?.  I know that   $$ \lim\limits_{n\to\infty}\left(1+\dfrac{1}{n}\right)^n=e, $$  So, can we say that $1^\infty=e$?  And, by logic, This product  $$\underset{\text{infinity times}}{1\cdot1\cdot\ldots\cdot1},$$ gives $1$ not other value.


Windows / Powershell version of the Unix 'which' Utility

The 'which' utility, when run with a parameter naming an executable, will tell you the first executable with that name it finds in your path, if found at all. This gives a good idea which version of the executable will be run. (Forgive me if this description is incomplete, but it conveys the general idea)  I'm looking for either a port of the 'which' utility, a Powershell command, or some other utility I'm not aware of that does the same thing.  I have looked at the following SO question (and will try the for loop logic in the selected answer). I'd prefer to have a single command that implements this functionality and want to see if that exists. If something like that doesn't exist, that logic would be fairly easily put into a script:     The  utility on CodeProject exists. It hasn't been updated in 6 years or so and, when built on my Win 7 machine with VS 2010, crashed upon running. I plan to do my due diligence to find out why it crashed, but don't have time until tonight.   Has anybody used another utility or command on Windows to emulate this functionality?


How to round a double (or String) to 2 decimal places in Java?

While there are many rounding questions answered in StackO., I could not quite translate this to my multi-part question. (I am not sure why the link at the top of my post says "answer is here"... because this feels more like a resource to me, one that, for a beginner, is very difficult to sift through. I would not have come up with the answer someone presented on my post, just by looking through all of that conversation and analyzing the link for RoundingMode on that page. I see part of the right code is there, but only after it has been pointed out to me by someone who knew the answer.)  1. I need to round my finalBill TextView field so that it is to 2 decimal places. I heard using BigDecimal is good, but don't know how to write it, or where to put it in my code (I am a beginner).  2. Would it be more wise to round the double variable (within my onClick methods), before I convert to a String? Or would it be better to round the final answer that is delivered in a String (in the finalBill TextView field)?  Right now, I get the final answer that has many, many decimals behind it. I just need 2.  Backstory: I am creating a tip calculator, and when the onClick method executes for each button (10%, 15%, and 20%)... this should calculate the new total bill that includes tip, and also give the numeric answer (which has already been converted to a TextView) in a number no more than 2 decimal points. Thanks for your help!  Here is my code: I only included the amount including the first method onTen, since this method is where the tip is calculated and where the rounding needs to happen. (Other buttons not included for simplicity sake).  package com.example.nonitips;  import java.math.BigDecimal; import java.math.RoundingMode;  import android.app.Activity; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView;  public class MainActivity extends Activity {      private EditText originalBill;     private double billWithTip;      String billString;     private TextView finalBill;     private Button btnTen;     private Button btnFifteen;     private Button btnTwenty;     double rounder = billWithTip;       @Override     protected void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         originalBill = (EditText)findViewById(R.id.originalBill);     }      public void onTen (View v) {         //Toast.makeText(this, "Tipping at 10%", Toast.LENGTH_SHORT).show();          btnTen = (Button)findViewById(R.id.btnTen);         //The button gets the setOnClickListener         btnTen.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {                 double bill = Double.parseDouble(originalBill.getText().toString());                 billWithTip = bill * 1.10;                 //Turns the answer back into a string                 String billString = String.valueOf(billWithTip);                 finalBill = (TextView)findViewById(R.id.finalBill);                 finalBill.setText(billString);             }         });      }  }


I want to make an user that have no home folder and no login ability.   sudo useradd -s /bin/false [demouser]   I omitted -m parameter since that makes the home folder for the demouser.   I did -s /bin/false option for making this demouser cannot login.    Have I done it right? Is the the option -s /bin/nologin the same as above?


"Could not chdir to home directory /home/me: No such file or directory"

I am using 12.04 on my server.  I created a new user using adduser me and passwd me and added it to sudo.  When I log in this is what I see.  Could not chdir to home directory /home/me: No such file or directory     $   I type bash and it begins to look "normal"  $ bash me@server:/$   How can I avoid typing bash every time I login?


convert base 64 string to byte array c++

I have this in powershell with hardcoded base64 dll:     $DllBytes64 = "base64dll" ...  ...  [Byte[]]$DllBytes = [Byte[]][Convert]::FromBase64String($DllBytes64)  I need to write the same things in C++ I'm using this lib for base64:  What i have now: string str = "base64dll"; auto s = base64::from_base64(str);  I need to convert in byte, and write to a file for example in C:\Temp\test.dll I tried to put in a vector but i fail, can someone help please?


How to boot to terminal (ubuntu 12.04/gtx660Ti)?

trying to install CUDA for my ubuntu 12.04LTS. Installed the NVIDIA drivers for GTX660Ti but haven't yet run the updates. The manual for CUDA says I should now move to a tty via Ctrl+Alt+F1 but that brings a black screen, and the monitor goes to sleep showing nothing. Ctrl+Alt+F7 brings me back though.  Thought I could instead modify the /etc/default/grub, uncommenting either one of these lines: -GRUB_TERMINAL=console -GRUB_GFXMODE=640X480 and then sudo update-grub. Both end me into a Error: No video mode activated, which will not leave, and I cannot access anything until I crash it so that I can go to recovery.  So mainly I would like to just install the CUDA, but if I could get my Ctrl+Alt+F1 to work I would like that too. I have tried several ways to fix it, and they all just make things worse. What should I do?  What I'm following btw:


What should I do if I cannot afford a journal Article Processing Charge?

I would like to publish an article open access, but I cannot afford the . I am based in the UK, so I do not qualify for some of the available fee reductions or waivers. I also do not have grant funding to coverage the fee. How can I obtain funding to cover the publication fee to make my research open access?


Can I (safely) use pip inside a script run with sudo

I have an install script to set up dependencies for a project, this means installing packages using pip and apt. My prefered method is to run the script as sudo ./install but then how do I drop sudo for pip (do I need to with --user)? #!/bin/sh  if [ $(id -u) -ne 0 ]; then     echo Please run as root     exit fi apt install pkg_a pkg_b pkg_c  # Is this fine? How do I drop sudo here? pip install --user pkg_d pkg_e pkg_f  The alternative is to have sudo in the script but I prefer the first option if it's possible #!/bin/sh  sudo apt install pkg_a pkg_b pkg_c pip install --user pkg_d pkg_e pkg_f


Find all real solutions for $x$ in $$ 2(2^x- 1) x^2 + (2^{x^2}-2)x = 2^{x+1} -2 . $$  I noticed that $$2(2^x- 1) x^2 + (2^{x^2}-2)x = 2^{x+1} -2=2(2^x−1)(x^2-1)+(2^{x^2}−2)x=0.$$  I know that $2^{n+1}-1$ will always be greater than $2^n-1$ for all positive integers. $2^{n-1}-1$ will always be less than $2^n-1$.  How do I solve this problem?


How many arrangements of a bookshelf exist where certain books must be to the left/right of other books?

The question at length is exactly this:     There are five distinct computer science books, three distinct   mathematics books, and two distinct art books. In how many ways can   these books be arranged on a shelf if one of the mathematics books is   on the left of all computer science book, and another mathematics book   is on the right of all the computer science books?   I have searched a ton online for a question that's even similar to this but have yet to find one. Most examples have set groupings of books to create an 'object' but none have the kind of modular specifications of this question.  I realize that there is ambiguity about if the math books are directly flush with the computer science books, or if they can be 'anywhere to the left/right' of the computer science books. I've attempted this question under the more challenging assumption and have gotten an answer as follows:  There are 4 different placements of two math books that will allow for the computer science books to be completely between the two.  1) 8 spaces between the two math books M__________M (1 way)  2) 7 spaces between the two math books: M_______M_ and _M_______M (2 ways)  3) 6 spaces: M______M__, _M______M_, __M______M (3 ways)  4) 5 spaces: M_____M___, _M_____M__, __M_____M_, ___M_____M. (4 ways)  Then I wanted to find the permutations of each of the ways above by the Rule of Product, and add them together by the Rule of Sum to get my final answer.  (1) 8 spaces: P(3, 2) * P(8, 8)   [Delimiting math books]  * [permutations in between]  (2) 7 spaces: P (3, 2) * P(3, 1) * P(7, 7) * 2  [Delimiting math books] * [Options for book outside of delimitation] * [Permutations in-between] * [number of ways to achieve 7 spaces]  (3) 6 spaces: P (3, 2) * P(3, 2) * P(6, 5) * 3  [Delimiting math books] * [options for 2 books outside delimitation] * [permutation in-between] * [number of ways to achieve 6 spaces]  (4) 5 Spaces: P (3, 2) * P(3,3) * P(5, 5) * 4  [Delimiting math books] * [options for 3 books outside delimitation] * [permutation in-between] * [number of ways to achieve 5 spaces]  Then my final answer would be (1) + (2) + (3) + (4). My worry is that I'm missing some duplicates somehow.  Also conveniently, I believe the total for 5 spaces would satisfy the simpler question if it is actually referring to permutations with the chunk MCCCCCM.  Thanks in advance! I'd love to see specifically what I'm doing wrong (if I am indeed wrong).


how to make blender render less from far objects?

(i use blender 2.79) in video games, the farther is the object the fewer details it has, and that of course to save memory but how to do it in blender  if you have 2 complex objects and one of them is closer to the camera than the other  how to make the farther object get less render?


Prove that $$x^n-1=(x^2-1)\prod_{k=1}^{(n-2)/2}[x^2-2x\cos{\frac{2k\pi}{n}}+1]$$ if $n$ be an even positive integer. Hence deduce that $$\sin{\frac{\pi}{32}}\sin{\frac{2\pi}{32}}\sin{\frac{3\pi}{32}}\cdots\sin{\frac{15\pi}{32}}=\frac{1}{2^{13}}$$  Attempt:  I am able to solve the 1st part of the problem and unable to solve the 2nd part that is the deduction part of the problem. Please help for the deduction part only.   Edit:  Using double angle: I can show that $$\sqrt{n}=2^{(n-1)/2}\sin{\frac{\pi}{n}}\sin{\frac{2\pi}{n}}\cdots \sin{\frac{(n-2)\pi}{2n}}$$  Please suggest suitable n and the please help me to complete the remaining part. I have taken n=32 but not able to complete the solution.


Physical reason behind having greater amplitude when driving frequency$ $ natural frequency

This is quoted from A.P.French's Vibrations & Waves:  If the driving force is of low frequency  relative to the natural frequency, we would expect the particle to move essentially with the driving force. This is equivalent in saying that $m\dfrac{d^2x}{dt^2}$ in $$m\dfrac{d^2x}{dt^2} + kx = F_0\cos\omega t$$ plays small role compared to the term $kx$. The amplitude is controlled by spring constant. On the other hand, at frequencies very large compared to the natural frequency, the opposite situation holds. The $kx$ becomes small compared to $m\dfrac{d^2x}{dt^2}$. In this case, we expect a relatively smaller amplitude of oscillation than the above case.  $\bullet$ Why does $kx$ become prominent in the first case & not in the second case? $\bullet$ What is the physical reason behind that the first case has greater amplitude & the second one smaller?


Why did he turn on the TV vs why the man turned on the TV

Why did the man turn on the TV ?      Why the man turned on the TV ?   Sometimes, I guess, I hear or see these two constructions, so what is the difference ? Does the second is more often in sopken language ? And do both of them are formal ?  Thank you


Can I bring my dog from the mainland U.S. to Hawaii?

I would like to bring my Chihuahua to Hawaii. She is microchipped, vaccinated for rabies, and licensed in California.   Can I bring her to Hawaii? Does any airline allow in-cabin pets on flights to Hawaii?


Where to download Ubuntu without bittorrent

Please could someone tell me where can I download Ubuntu 32bit without using a torrent? Thanks


How to list only root packages, without their dependencies?

I'm trying to see witch packages I've installed, but when I dpkg -l I got a big list of packages and their packages dependencies.  There's a way to get only the list of packages explicitly installed?  Ex:  apt-get install mysql-server   Thats also installs mysql-common  I want that when i list my packages only the mysql-server is showed.


How can I remove the little white insects from semolina and flour?

Sometimes I feel that little white insects seem in flour and semolina , specially in rainy season. The flour and semolina attacked  these insects can be used ? If yes then how can I remove these insects from flour and semolina ?


Pay in local currency or in dollars with a credit card in Peru?

Until now, I've only seen credit card charges displayed on the POS terminal under a country's own currency.  However, in Peru, many terminals display both the local soles and my card's usual currency, Canadian Dollars and the vendor asks me which currency I would prefer to pay in, which I can pick.  Now, until this trip, I had come to expect that credit card companies will profit handsomely at my expense by extra charges and perhaps a less than ideal exchange rate.  I assume this is still the case.  My question in this case is, will those charges, and the final cost to me, be less if I pay in local soles or if I pay in CAD $?  Are the displayed CAD/Soles amount, and therefore an implicit exchange rate, telling me the whole story?  Assume, if you're not sure about CAD $ specifics, that the choice is between USD $ or soles.  Also fine if you have experience with a similar system of currency payment choices in a country other than Peru, I assume credit cards operate relatively similarly across countries.  But I am really looking for people who went through it and did the math upon their return.  In other words - better to pay in soles / better to pay in dollars / about the same?  Note:  the vendor is not the one offering me a choice between say 70 soles or 25 CAD and therefore setting the exchange rate, at that point they don't even know where I come from.  Its the VISA terminal itself that recognizes my card.  So, whatever the merits or not of paying in local currency, that is NOT driven by the vendor's choice of exchange rate (which, yes, I would assume would be worse than VISA's).


How to create a noise texture like this website's

How would I go about making a texture similar to the one used throughout :     Is it some kind of noise pattern?


Bounds on off-diagonal entries of a correlation matrix

Assume that all the entries of an $n \times n$ correlation matrix which are not on the main diagonal are equal to $q$. Find upper and lower bounds on the possible values of $q$.  I know that the matrix should be positive semidefinite but how to proceed to get the upper and lower bounds?  Thanks!


Displaying the "description" from an RSS/ATOM feed in PHP

I want to know how display the last three "descriptions" from an RSS/ATOM feed on a PHP page.     I am extremely inexperienced with RSS/ATOM feeds and I am not sure if I have word this correctly or if it is even possible.


Shouldn't the if(text[i]=='E') contain 3 equal to symbols instead of 2 in the js code here?

I am new to learning JavaScript,I found this code, I had learnt earlier that equality is checked using 3 equal symbols, so shouldn't this program crash(it doesn't surprisingly)  /*jshint multistr:true */  text = "Blah blah blah blah blah blah Eric \ blah blah blah Eric blah blah Eric blah blah \ blah blah blah blah blah Eric EdiEk";  var myName = "Eric"; var hits = [];  // Look for "E" in the text for(var i = 0; i < text.length; i++) {     if (text[i] == "E") {         // If we find it, add characters up to         // the length of my name to the array         for(var j = i; j < (myName.length + i); j++) {             hits.push(text[j]);         }     } }  if (hits.length === 0) {     console.log("Your name wasn't found!"); } else {     console.log(hits); }   The program checks if your name or something similar to it is in the text[]


Why does the Stack Exchange site prefer questions that can be answered, not just discussed?

Most other sites seem to have questions that can only be discussed or answered.


How to model a ridged dial or gear shape

Having a difficult time finding the correct name for this, but I have some photos.  I'm specifically trying to model a sniper scope, and some of the circular rings on it have ridges on them, but I'm not sure how to model the ridges/grooves.  Like this:    Or these google searches might show what I'm trying to explain better:  Sniper scope:   Camera Dial:   Essentially a ring with ridges on it, I'm not sure how to model it.  The poke tool is definitely not working for me, and I cannot add loop cuts to everything. What's the best method for going about modeling this?


I have a div with overflow:hidden, inside which I show a phone number as the user types it. The text inside the div is aligned to right and incoming characters are added to right as the text grows to left.  But once the text is big enough not to fit in the div, last characters of the number is automatically cropped and the user cannot see the new characters she types.  What I want to do is crop the left characters, like the div is showing the rightmost of its content and overflowing to the left side. How can I create this effect?


What does "Reviews Completed" status mean in Springer?

I submitted a paper to one of the Springer Journals through Editorial Manager almost 5 months back. The status changed from Editor Assigned to Under Review and now it is showing "Reviews Completed" since past five days. Can anybody suggest what does it actually mean and is there any other stage before the decision is made?  Does it give any indication about the reviewers not rejecting my submission?


What's new in Okami HD compared to the original?

So after hunting around the various review sites and message boards, I still have one question about this game:  Aside from the updated graphics, is there anything new in this version of the game?  I've played the Wii version, as well as the Okamiden game for the DS.


Can entropy ever decrease in an isolated system?

Consider the simplest such system: a gas-filled chamber. I understand that, were all the gas particles concentrated in one corner, the entropy of the chamber will be lower than the entropy of the same chamber but homogenized. If so, the two states do not actually represent the same macro-state, hence we will never expect particles in a homogeneous gas chamber to spontaneously segregate. This can be verified experimentally by trying to separate the gas into distinct regions, one of high pressure and another one with vacuum. The more we try to segregate, the harder it gets showing that this separation will never happen spontaneously.However, such a chamber is often [erroneously?] represented as pebbles on a board:  But pebbles remain in the segregated state indefinitely, whereas gas particles always homogenize spontaneously and always resist segregation as discussed.Therefore, can there EVER be any spontaneous fluctuations that lowers the entropy (segregate the content) of such an isolated system?


Deriving conserved charges from the equations of motion

It is very well established how to derive conserved charges associated to the symmetries of Lagrangian using the Noether's theorem. Also in the Hamiltonian formulation, we know how to derive the charges associated to symmetries of the Hamiltonian action, using the symplectic structure etc. My question: Suppose I have a set of equations without knowing the explicit action or Hamiltonian. I realize that the equations of motion are invariant or covariant under some transformation. Is there a way to associate conserved charges (or better conserved currents) associated to this symmetry transformation without using Lagrangian or Hamiltonian? This question was answered  for the very special case of a system of particles where the equations of motion take a "natural form" $m_i\ddot{{\vec x}}_i=-{\vec\nabla} V(x^j)$. However, this is very limited and does not apply to a field theory or a gauge theory in general (e.g. consider general relativity without any special gauge condition). Application A good example of this issue is the Electric-magnetic duality symmetry. Remind that Maxwell equations are invariant under the electric-magnetic duality $(E,B)\to (B,-E)$. With some effort, this symmetry can be also realized at the level of the action as shown originally by Deser and Teitelboim (). Then using the Noether procedure, it turns out that the Noether charge corresponding to duality is helicity which is a physical observable. In linearized GR same thing happens. The eom is duality symmetric. One can also find a duality invariant action () However, the problem becomes more interesting in full GR. In this case, the Einstein equations still have an electric-magnetic duality under rotating the electric and magnetic parts of the Weyl tensor into each other (see e.g.  or section 7.2 of the book by Christodoulou and Klainerman). However, this symmetry cannot be realized at the level of the action. Indeed there is a no-go theorem by Deser et al. () showing that the duality symmetry cannot be realized at the level of the action. So the question is whether there is a conserved quantity that correspond to the duality symmetry in GR or not?


A fly flying to $300$ points, but each time it increases its flying distance by $1.$

There are 300 points around circle. A fly sits in one of the points. It starts moving clockwise. At first the fly moves to the next point. Then it skips one point. Then it flies skipping 2 points, then 3 points and so on. Will the fly eventually visit all the points? I am not sure where to start. I have tried to shown it for a smaller case with the number of points being 6, but it doesn't seem to work. How can I generalize it?


I've gotten interested in describing a circle rolling on an ellipse; specifically, the curve traced out by a point on the circumference of the circle. I want a symbolic solution to the general case, radius $r$, axes $a$ and $b$. I've written nine polynomial equations in terms of various angles and lengths.  Exactly what "solution" means is subject to debate.  Let $(u,v)$ be the point on the circle. Similar to the cycloid, I would like an equation for $u$ in terms of a "natural" angle in the problem.  Similarly, an equation for $v$.  Perhaps it is necessary to have a differential equation, so maybe $du/dt$, $u$, and $t$, where $t$ is an angle in the problem.  I would have thought this was known, but I can't find it anywhere.


"Why has this happened to me today?", I thought.


Proving that $\lim\limits_{x \to 0}\frac{e^x-1}{x} = 1$

I was messing around with the definition of the derivative, trying to work out the formulas for the common functions using limits. I hit a roadblock, however, while trying to find the derivative of $e^x$. The process went something like this:  $$\begin{align} (e^x)' &= \lim_{h \to 0} \frac{e^{x+h}-e^x}{h} \\ &= \lim_{h \to 0} \frac{e^xe^h-e^x}{h} \\ &= \lim_{h \to 0} e^x\frac{e^{h}-1}{h} \\ &= e^x \lim_{h \to 0}\frac{e^h-1}{h} \end{align} $$  I can show that $\lim_{h\to 0} \frac{e^h-1}{h} = 1$ using L'Hôpital's, but it kind of defeats the purpose of working out the derivative, so I want to prove it in some other way. I've been trying, but I can't work anything out. Could someone give a hint?


MicroSD content disappeared and turned into one big unaccessible file

I put some 8Gb MicroSD card in Video Recorder and recorded some video onto it. Then I got a message, that card is full. I plugged it into computer's card reader and saw, that card was full of Android filesystem files from some old device. Also I found two video I just recorded. I saw these videos and at the moment I was watching second one I got a message, that data is unreadable.  After that when I am looking at the card I only see System Volumne Information directory from Windows and one big 3.5G file with garbaged name. This file probably encapsulates entire flash card content.   I can't open or copy this file.  How can I restore data in this situation?


YA dystopia novel of battle school with unusual military control scheme

Some sort of battle school (no, not Ender's Game), where teens are being trained as military commanders.   The control system for their army hinges around some sort of system that requires extremely fine motor control -- being able to "push" around digital representations of military units using a special interface that interprets minute finger movements.  The boy protagonist eventually meets a girl in the battle school, and is astonished to learn that most people do not live as well as he does -- for instance, he gets a fresh jumpsuit outfit every day and disposes of the old one; this is a luxury.  One scene I recall is them kissing for a moment in some sort of underground passageway; the boy protagonist notes the exact length of the kiss, as he has been trained to have heightened time perception.  I don't recall much about other commander characters; I think they have different special abilities, and one other major character might have physical deformities, possibly because of postwar-radiation-related birth defects.  They have been training for an upcoming, prearranged final battle between all the existing national governments; the military units are very possibly robotic or entirely digital in nature, so as to avoid wasting materiel / human life.    They ultimately win the battle, just barely; I think the girl protagonist gives them an edge in the competition by hacking the timing / control system in favor of their team, causing a discrepancy which only the boy protagonist notices due to his heightened perceptions.  It was agreed that the winning government gets dominion over one of the few islands of land left that was not irradiated in some previous war; the protagonists get to live there as a reward for their victory.  I believe the boy protagonist later realizes he's gradually losing his ability to exactly quantify the passage of time.  Published no later than 2004, likely somewhere between 1980-2000, probably sometime in the '90s.


What are the pros and cons of engineered hardwood?

Are there any downsides to engineered hardwood? I'm looking to install hardwood in dining room and kitchen areas.


In series 5 final the big bang how did the doctor get out of the pandorica?

I was wondering in the grand final of series 5 the big bang how ever did the Doctor manage to get out of the pandorica as it has never come up. I've also tried looking it up in My Doctor who encyclopedia but had no luck finding anything


Add my C# windows application as a printer in windows

I am a fresher in c#. I have developed an application that can convert a postscript file(.ps) to formats like PDF,JPEG, ets,. My intention is to develop a pdf printer. So how do I add this application as a printer in windows xp or above. Or say how do I get the PS file when CTRL+P is pressed on any windows application.  This is not a network printer, its a printer that needs to be assigned to a local print port and not a network port.


RSync incremental backups, backing files that haven't changed. Does file access time cause a re-backup?

I backup my LAMP server using RSync over SSH.  Currently, it's on an hourly incremental schedule.  From a 14GB full backup, it's backing up a further 15~MB hourly.  Looking at the files it's backing up again, I think most of these haven't changed.  Does the file last accessed time attribute mean the file has technically changed and would be re-backed up?


I'm pretty new to java regexp and trying to compile a Pattern that simplifies this:  String str1; String str2; String str3; String str4; String str;  if ((str.contains(str1) || str.contains(str3)) &&         str.contains(str3) || str.contains(str)) {     return true; } else {     return false; }   I figured out I can do the OR with "|" but how do I compile the AND?  I want to be able to compile the pattern and check many strings with good performance.  EDIT:   I got this now :  private static boolean checkPatternOR() {      String patternString = "foo"  ;      Pattern pattern = Pattern.compile(patternString, Pattern.CASE_INSENSITIVE);      Matcher matcher1 = pattern.matcher("foo bar");     Matcher matcher2 = pattern.matcher("something else");       System.out.println("does it match? " + (matcher1.lookingAt() && matcher2.lookingAt()));      return true;  }   How would I merge matcher1 and matcher2 into one?


Though often heard, often read, often felt being overused, I wonder what are the precise definitions of invariance and covariance. Could you please give me an example from field theory?


How can I raise the bounty on my question?

I read that you can assign multiple bounties to a question, but I fail to see a way to do this. My question:


getting null pointer exception :: struts 1.3

Getting null pointer exception at line --  if(lForm.getUserId()!=null && lForm.getPassword()!= null){   Please help  package com.app.action; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;   import org.apache.struts.action.Action;  import org.apache.struts.action.ActionForm;  import org.apache.struts.action.ActionForward;  import org.apache.struts.action.ActionMapping;    import com.app.form.LoginForm;  public class LoginAction extends Action {    @Override  public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {  LoginForm lForm = (LoginForm) form; String forwardString = "";  //lForm.setUserId("shats"); try{     if(lForm.getUserId()!=null && lForm.getPassword()!= null){ if(lForm.getUserId().equals("shats") && lForm.getPassword().equals("admin")) {     forwardString = "success"; } else {     forwardString = "failure"; }     } } catch(Exception e){     System.out.println("Error ::::::"+e); } forwardString = "success"; return mapping.findForward(forwardString);  }  }


Does the PS4 or Xbox One need an internet connection to work?

My friend does not have the internet. They will not have the internet under any circumstances, but they want to buy a new console now that the Xbox 360 is obsolete. We have both heard that both the PS4 and Xbox One REQUIRE connection to work at all by downloading some patch first.  That isn't an option for me (and no they wont bring it here I already asked and they refused with the words "I don't go near the net ever except if forced to at work").  Will either console just work out of the box?  Whichever she gets isn't ever going to be updated unless the discs of games do so. Its never going to be online, she isnt interested in online gaming at all, doesn't have an internet, or even email.  She won't even have a smartphone or MP3 player.


Is "could" interchangeable with "can"?    for example, there are coversations like these:    example. 1       A: I could run faster than you.   B: No way.     In this case, the "could" is referring to the less certain possibility of a skill in the present time.    example. 2       A: Even that small stadium could have ten thousand people.   B: Isn't that too small for ten thousand people?     In this case, the "could" is referring to the less certain possibility of a capability as a fact.    I think these "could"s in the two examples express the same things as "can", and the difference from" can" is just that "could" is less certain about possibilities.    However, I'm not sure if it's allowed to use "could" like those, because "could" is used when expressing hypothetical or conditional things like "would". Are the "could"s acceptable?    Thank you.


What should I do if I deleted all my bad low quality unanswered questions and I am permanently blocked from asking and answering questions?

I deleted all my bad low quality unanswered questions and they are unrecoverable, so I am unable to fix or improve my bad low quality unanswered questions.  I am also permanently blocked from asking questions and answering questions, so I have no way to contribute to the community in any way.  Is it a sign that I am doomed forever? I guess that yes I am.  Well I still can use email of someone else if I want to post, but with my email I can't post anymore forever. Is that true? I guess that yes it is.


Ubuntu /dev/loopX - Way too many mounted units

I am not a very experienced user, specially regarding system's technicalities such as this one. All I know is that when I first installed Ubuntu, I used the command df -h to check my disk space. It usually went like this  user@laptop:/home$ df -h Filesystem      Size  Used Avail Use% Mounted on udev            2.9G     0  2.9G   0% /dev tmpfs           585M  1.8M  583M   1% /run /dev/sda2       457G  104G  331G  24% / tmpfs           2.9G   29M  2.9G   1% /dev/shm   For the last couple of months, however, the results have been as follows:  user@laptop:/home$ df -h Filesystem      Size  Used Avail Use% Mounted on udev            2.9G     0  2.9G   0% /dev tmpfs           585M  1.8M  583M   1% /run /dev/sda2       457G  104G  331G  24% / tmpfs           2.9G   29M  2.9G   1% /dev/shm tmpfs           5.0M  4.0K  5.0M   1% /run/lock tmpfs           2.9G     0  2.9G   0% /sys/fs/cgroup /dev/loop0      141M  141M     0 100% /snap/gnome-3-26-1604/70 /dev/loop1       17M   17M     0 100% /snap/communitheme/1273 /dev/loop2       13M   13M     0 100% /snap/gnome-characters/117 /dev/loop3      3.8M  3.8M     0 100% /snap/gnome-system-monitor/57 /dev/loop4      3.8M  3.8M     0 100% /snap/gnome-system-monitor/54 /dev/loop6      2.3M  2.3M     0 100% /snap/gnome-calculator/222 /dev/loop8      141M  141M     0 100% /snap/gnome-3-26-1604/62 /dev/loop9      2.4M  2.4M     0 100% /snap/gnome-calculator/199 /dev/loop10     140M  140M     0 100% /snap/gnome-3-26-1604/64 /dev/loop12     227M  227M     0 100% /snap/pycharm-community/79 /dev/loop13     227M  227M     0 100% /snap/pycharm-community/83 /dev/loop14     3.8M  3.8M     0 100% /snap/gnome-system-monitor/51 /dev/loop15      43M   43M     0 100% /snap/gtk-common-themes/701 /dev/loop16     227M  227M     0 100% /snap/pycharm-community/85 /dev/loop17      88M   88M     0 100% /snap/core/5328 /dev/loop21      13M   13M     0 100% /snap/gnome-characters/103 /dev/loop18      88M   88M     0 100% /snap/core/5548 /dev/loop5       13M   13M     0 100% /snap/gnome-characters/124 /dev/loop20      15M   15M     0 100% /snap/gnome-logs/43 /dev/loop23      15M   15M     0 100% /snap/gnome-logs/45 /dev/loop22     2.3M  2.3M     0 100% /snap/gnome-calculator/238 /dev/loop24      35M   35M     0 100% /snap/gtk-common-themes/319 /dev/loop7       17M   17M     0 100% /snap/communitheme/1226 /dev/loop11      15M   15M     0 100% /snap/gnome-logs/40 /dev/loop19      17M   17M     0 100% /snap/communitheme/1201 /dev/loop25      87M   87M     0 100% /snap/core/5145 /dev/sda1       511M  6.1M  505M   2% /boot/efi tmpfs           585M   88K  584M   1% /run/user/1000   As you can see, not only do I have 5 temporal filesystems, but also a ridiculous amount of /dev/loop entries. I have tried to look for a solution on the internet from time to time. The problem is, I dont even know what is it that I am looking for. The closest I got was to some post talking about inodes, and after barely getting a grasp of what an inode is, I couldn't get anywhere near finding someone undergoing the same situation.  To be honest, I don't know/think this is a problem. But I certainly do not like it. I would like to know what are these things, whats their relationship with the inodes (if I run df -i -h I get a similar result, from what I guess are the corresponding inodes to these mounts), what is the reason for their unusual multiplicity, should I get rid of most of them and, if so, how to do it.  Thanks in advance :D!


Significance of logistic regression coefficients

Let's say I fit logistic regression with 2 predictors (x1, x2) and binary outcome (y). When I fit two separate regression y~x1 and y~x2 coefficients for predictors are significantly different from 0, meaning that their CIs don't contain 1 (for Odds Ratios).   However when I fit logistic regression with both parameters together, y~x1+x2, coefficients are no longer significantly different from 1. Why does it happen? How could this be explained?  Here is the particular example: I have variables x1, x2, and I consider predictors as x1 and x2/x1.  summary(glm(as.formula(data2[,1]~data2[,2]), family=binomial(link="logit"),              na.action=na.pass))   gives me:  (Intercept) -1.05526    0.29529  -3.574 0.000352 *** data2[, 2]   0.24653    0.09686   2.545 0.010917 *   summary(glm(as.formula(data2[,1]~I(data2[,2]/data2[,3)), family=binomial(link="logit"),              na.action=na.pass))   gives me:  (Intercept)               0.43475    0.39187   1.109  0.26725    I(data2[, 3]/data2[, 2]) -0.06889    0.02554  -2.698  0.00699 **   while regression with both variables,   summary(glm(as.formula(data2[,1]~data[,2]+I(data2[,2]/data2[,3)),              family=binomial(link="logit"), na.action=na.pass))   gives me:  (Intercept)               -0.2278     0.5740  -0.397    0.692 data2[, 2]                 0.1580     0.1065   1.484    0.138 I(data2[, 3]/data2[, 2])  -0.0456     0.0284  -1.606    0.108   Correlation between variables is -0.504 and is significantly different from 0.   Does significantly different from 0 correlation lead to this situation? If so, how could one justify this?


What are the official characters in tengwar for numbers?

I've seen different depictions for numbers in tengwar online, what are the official characters to depict number in tengwar? I'm particularly interested in the number 3.


How to ask what is your number in the siblings or to your parents.?


iCloud says "Password is wrong", but I think it's correct. How should I proceed?


Prove that the product of two continuous functions is continuous

I was trying to prove an important theorem concerning continuous functions, namely that the product of two continuous functions is continuous. I am nearly at the end of the proof but I do not understand the last step my teacher made... I'm sure some of you is able to help me out :) Thanks in advance!  Theorem  Let $f, g\colon \Bbb R \to\Bbb R $ be continuous. Then $F\colon \Bbb R\to\Bbb R$ defined by $F(x) = f(x)g(x)$ is continuous.  Proof  Let $f, g\colon \Bbb R \to\Bbb R $ be given such that $f$ and $g$ are continuous.  Let $F\colon \Bbb R\to\Bbb R$ be defined by $F(x) = f(x)g(x)$. We want to show: $F$ is continuous, that is, for all $a \in\Bbb R$, for every $\epsilon > 0$, there exists some $\delta > 0$ such that for all $x \in \Bbb R$ with $|x - a| < \delta$, $|F(x)-F(a)| < \epsilon$.  Let $a \in\Bbb R$ be given. Let $\epsilon > 0$ be given.   Let $\delta_f > 0$ be such that for all $x \in\Bbb R$ with $|x-a| < \delta_f$, $|f(x)-f(a)| < \frac\epsilon{2(|g(a)| + \epsilon)}$. Such a $\delta_f$ exists since $f$ is continuous.  Let $\delta_g > 0$ be such that for all $x \in\Bbb R$ with $|x-a| < \delta_g$, $|g(x)-g(a)| < \frac\epsilon{ 2|f(a)| + 1}$. Such a $\delta_g$ exists since $g$ is continuous.  Let $\delta_3 > 0$ be such that for all $x\in\Bbb R$ with $|x-a| < \delta_3$, $|g(x)-g(a)| < \epsilon$, which implies $|g(x)| < |g(a)| + \epsilon$. Such a $\delta_3$ exists since $g$ is continuous.  Choose $\delta = \min\{\delta_f, \delta_g, \delta_3\}$.  Then for all $x \in\Bbb R$ with $|x-a| < \delta$:  $$\begin{align}|F(x) - F(a)| &= |f(x)g(x) - f(a)g(a)| \\ &= |f(x)g(x) - f(a)g(x) + f(a)g(x) - f(a)g(a)| \\ &\le |f(x)g(x) - f(a)g(x)| + |f(a)g(x) - f(a)g(a)|\\ &= |(g(x)[f(x) - f(a)]| + |f(a)[g(x) - g(a)]|\\&= |g(x)| * |f(x)-f(a)| + |f(a)| * |g(x) - g(a)| \\ &< [|g(x)| + \epsilon] \cdot \frac \epsilon {2(|g(a)| + \epsilon)} + |f(a)| \cdot |g(x) - g(a)| \\ &= \frac\epsilon{2 + |f(a)| \cdot |g(x) - g(a)|}\end{align}$$  Problem  Now we need $|f(a)| \cdot |g(x) - g(a)|$ to be equal to $\frac \epsilon 2$ so that we have $\frac\epsilon2+\frac\epsilon 2= \epsilon$ (which completes the proof). The problem is I do not see why/how $|f(a)| \cdot |g(x) - g(a)|$ is equal to $\frac\epsilon2$. Or is there maybe an error somewhere?


What is the intuition behind the score function?

tells us that the score plays an important role in the Cramér–Rao inequality. It also phrases out the definition:  $$V = \frac{\partial}{\partial \theta} \log{L(\theta; X)}$$  However, I cannot find an intuitive explanation of what this quantity expresses. Obviously, it somehow measures how a small change of $\theta$ will affect the log-likelihood of the observed data $X$, but what exactly does that mean?  The wikipedia article also mentions that the expected value $\mathbb{E} [V \mid \theta] = 0$. Can this be interpreted somehow?  Going a bit further, in class we were told that the Fisher information (for which I have no intuitive understanding either) is $I(\theta) = \mathbb{E} [V^2 \mid \theta]$. Combined with $\mathbb{E} [V \mid \theta] = 0$ that would imply $I(\theta) = \text{Var}[V]$, is this correct?  Thanks in advance.  PS: This is not homework.


Datatables Delete button is not working on other pages except first

I am using datatables. I have action column in the table in which one delete button and i am using ajax post function to delete any row. But Delete button is only working on the first page. It is not working on other pages.  Here is my delete button.

            #	         Resource Person	         Title/Topic	          Date 	         Actions

     <?php      $sql = "SELECT * FROM seminar";     $result = $con->query($sql);      if ($result->num_rows > 0) {                                     // output data of each row         $count = 1;         while($row = $result->fetch_assoc()) { ?>
             <?= $count ?>	             <?= $row['person'] ?>	             <?= $row['topic'] ?>	             <?= $row['date'] ?>	                              <button class="btn btn-danger delete_seminar" value="<?php echo $row['id'] ?>"> </button>                 <button class="btn btn-info" onclick="location.href = 'addRecord.php?id=<?php echo $row['id'] ?>';"></button>
         <?php $count++; }      }else{         echo "
No Record Found
";      }     ?>
             And my jquery function.  $('#example').DataTable();     $(function() {         $(".delete_seminar").on('click', function(event) {              if (confirm("Are you sure?")) {                 var data = $(this).val();                 $.post('requests/seminars.php', {delete_sem: data}, function(data) {                     if (data == "delete") {                         location.reload();                     }else{                         alert(data);                     };                  });             }          });         })   I don't know how to resolve this problem. Please help me to come out from this problem.


Why can't I change the hostname of my server using sudo?

From a user that is part of the sudoers group, I can normally run any command by doing sudo <command>  But the following command fails stating "Permission denied"  sudo echo "myhostname" > /etc/hostname   It doesn't even ask me for the password. How do I change the hostname ?


Source: RMO 2019, question 3  Let $a,b,c$ be positive real numbers such that $a+b+c=1$. Prove that $$\frac{a}{a^2+b^3+c^3}+\frac{b}{b^2+c^3+a^3}+\frac{c}{c^2+a^3+b^3}\leq \frac{1}{5abc}.$$  I tried using Holder's inequality but couldn't get to the desired result.


when installing scangear (using scangearmp-mp230series2.0-1-deb) for canon pixma mp230 it stops with    Error: Dependency is not satisfiable: scangearmp-common (>= 2.00),      and scanimage -L responds   No scanners were identified. If you were expecting something different, check that the scanner is plugged in, turned on and detected by the sane-find-scanner tool (if appropriate). Please read the documentation which came with this software (README, FAQ, manpages).


How to suppress a short circuit to prevent fuses from blowing

I have a circuit that is modular and one of the modules involves interfacing from an external relay.  Now this sub-module has a fuse set to blow a bit below what the main module's max current. (why put a fuse when the main module has over current protection? So that when this sub module fails it wont take the whole system down with it) This sub modules can cater upto 24 external relays and in the image below i will be showing how one channel is setup  What i would like to protect is the fuse from blowing from a false short circuit(not really false, since it is doing its job) in the cenario that the user might incorrectly wire the connection and shorts pin A and pin B. I need a current limiting solution so that the fuse wont blow up and the user of the sub module can rewire and try again.    The circuit is designed to trigger one relay at a time, a signal will be sent by a portexpander(not shown in picture) to the bs138 mosfet to open. the signal typically last around 250ms - 1000ms.   I have considered a polyfuse but it to slow to react the main module protection will trip first. Another is adding a resistor in series with the relay line but it is either a bulky high watt rated resistor or a high value resistor that might not make the relay trigger because of voltage drop.  there is also the problem since there is a short the power to the sub-micro controller will be cut, so this protection circuit i am looking for would probably happen in either series or parallel of the connection for the external relay   I need current limiting solution between pin A and pin B so that when A and B is shorted by the user and the mosfet turns on the fuse wont blow   how do you recommend to solve this problem, Thank you.


A book about cloning, sentient ship and others

A few years ago I read a book and I am trying to find it again any help would be appreciated.  As I remember it was an older book where the protagonist gains consciousness on a space ship thats gained sentience (this may be where I'm wrong as I cannot remember if its sentient or just gone rogue), the crew has been cloned over many generations and have been perverted into almost monsters. The protagonist tries to fix the problem.  The book ends with the actual crew waking up and exiting the space craft which isn't in deep space but in a sea and they find evidence of what had happened.


Find $\lambda\in \mathbb{C}$ s.t. $\exists$ entire $f$, s.t. $f(z)=f(\lambda z),~\forall z\in\mathbb{C}$

I want to find all $\lambda \in \mathbb{C}$ such that there exists an entire non-constant function $f$ with $f(z)=f(\lambda z)$ $\forall z \in \mathbb{C}$.  My idea was the following: Since $f$ must be entire on the whole complex plane it can be represented as taylor series around $0$. So I get then in total  \begin{align*} \sum\limits_{n=0}^\infty \frac{f^{(n)}(0)}{n!}z^n=f(z)=f(\lambda z)=\sum\limits_{n=0}^\infty \frac{f^{(n)}(0)}{n!}\lambda^{n}z^n. \end{align*}  Now I (hope I can) conclude that  \begin{align*} f^{(n)}(0)=f^{(n)}(0)\lambda^{n}. \end{align*} Therefore, either $f^{(n)}(0)=0$ or $\lambda^{n}=1$ must hold.  First I conclude that $|\lambda|=1$ must hold, therefore $\lambda=e^{i\theta}$ for some $\theta \in [0,2\pi].$ If now there exists $n\in \mathbb{N}$ such that $\theta=\frac{2\pi}{n}$ then I have $\lambda=e^{i\frac{2\pi}{n}}$ and therefore $\lambda^n=1$. For such functions I might be able to define a entire function $f$, such that all derivates in $0$ vanish except all $kn$ derivatives in $0$.  I just wonder if those are all and my thoughts were correct? Thanks in advance.


How do I switch windows using ALT+ TAB in Ubuntu 18.04?

I have opened 2 new windows of Chrome in Ubuntu. How do I select them using ALT+TAB? Every time I need to use mouse for this. Is there any way to do like in Windows?


Err:17 http://us.archive.ubuntu.com/ubuntu focal-updates/universe amd64 DEP-11 Metadata   Hash Sum mismatch   Hashes of expected file:    - Filesize:762382 [weak]    - SHA256:6992cdbbeec75ab9a81f82dfe79b787bbe0da0587ddbb71090e3f5a1d6f14794    - SHA1:c8ad07aa2316c5db1251db7ba3c8cc83d74deded [weak]    - MD5Sum:e8523de342151179aac680d249b86bed [weak]   Hashes of received file:    - SHA256:ee0640fcd2f7494c1e038f2aa14b91f3e4bcd1a7262052e981b40f5cabf1d22a    - SHA1:c8ad07aa2316c5db1251db7ba3c8cc83d74deded [weak]    - MD5Sum:e8523de342151179aac680d249b86bed [weak]    - Filesize:762382 [weak]   Last modification reported: Tue, 29 Sep 2020 00:30:01 +0000   Release file created at: Tue, 29 Sep 2020 01:31:09 +0000 Fetched 218 kB in 3s (83.8 kB/s)    Reading package lists... Done E: Failed to fetch store:/var/lib/apt/lists/partial/us.archive.ubuntu.com_ubuntu_dists_focal-updates_universe_dep11_Components-amd64.yml.xz  Hash Sum mismatch    Hashes of expected file:     - Filesize:762382 [weak]     - SHA256:6992cdbbeec75ab9a81f82dfe79b787bbe0da0587ddbb71090e3f5a1d6f14794     - SHA1:c8ad07aa2316c5db1251db7ba3c8cc83d74deded [weak]     - MD5Sum:e8523de342151179aac680d249b86bed [weak]    Hashes of received file:     - SHA256:ee0640fcd2f7494c1e038f2aa14b91f3e4bcd1a7262052e981b40f5cabf1d22a     - SHA1:c8ad07aa2316c5db1251db7ba3c8cc83d74deded [weak]     - MD5Sum:e8523de342151179aac680d249b86bed [weak]     - Filesize:762382 [weak]    Last modification reported: Tue, 29 Sep 2020 00:30:01 +0000    Release file created at: Tue, 29 Sep 2020 01:31:09 +0000 E: Some index files failed to download. They have been ignored, or old ones used instead.


$(\mathbf{v} \cdot \nabla) \mathbf{v}$ Notation in Euler equation (fluid dynamics)

Main question: Can I interpret $(\mathbf{v} \cdot \nabla) \mathbf{v}$ as $\nabla v \cdot v$?  My question comes from the wikipedia page on . I captured the relevant parts below:  The part that confuses me is the notation $${\partial\mathbf{u} \over \partial t} + (\mathbf{u} \cdot \nabla) \mathbf{u} = -\nabla w + \mathbf{g}$$ When I tried to derive the equation myself, using the chain rule, I got ${D\mathbf v(x,t) \over Dt}= \nabla v \cdot x'(t) + \frac{\partial}{\partial t} v(x,t) = \nabla v \cdot v + \frac{\partial}{\partial t} v(x,t) $. Assuming I did not make mistakes, can I interpret $(\mathbf{v} \cdot \nabla) \mathbf{v}$ as $\nabla v \cdot v$?


Exclude multiple domains in Google Analytics

I want to exclude multiple domains from all my reports to prevent referral spam, but as more and more of these popup I'd like to do so via a single filter..  I tried adding a filter with settings:     Filter Type 'predefined'   Exclude   Traffic from the ISP domain   Tried both 'equal to' and 'that contain'   But it won't let me enter any of these values:  semalt|buttons-for-websites|social-buttons|darodar\.com semalt,buttons-for-websites,social-buttons,darodar\.com semalt.combuttons-for-websites.comsocial-buttons.com|darodar.com   None of these are seen as a valid domain name.  Can I exclude multiple domainnames via a single filter?


How to get an alert when new questions are posted on Stack Overflow?

I am new to Stack Overflow. Now I am working as an iPhone programmer. I want to develop my skill in  and iOS. How do I get alerts, when new questions are posted with tags related to Objective-C and iOS?


Are the SPECIAL video clips available to view other than during game loading?

I'd like to view the S.P.E.C.I.A.L. video clips that are randomly shown during the initial game load.  Are they available to view elsewhere in the game?


How to use the Division Algorithm (polynomial rings) and evaluation map to prove the Remainder Theorem?

I am trying to use my proof of the Division Algorithm and evaluation map to prove the Remainder Theorem which states:   Let F be a field, a in F, f in F[x]. Then the remainder when f is divided by the polynomial x - a is equal to f(a).  I would like some guidance as to where to start. Thanks in advance.


Why do my vector graphics look like %$* when printed?

this is a newbie question: I only made a bit of interface design in my life, and now I have to produce some printables - I used my old faithful Fireworks because Photoshop I don't know how to use quickly, I made documents 300 dpi, created vector graphics solid colour fill, RGB (well, I knew only the Pantone hex colors but Fireworks also puts the RGB number, don't know which one denotes the file) but whenever I try to print the colors are all meh and not very vivid, I exported PNG and JPEG highest quality, and I just don't seem to get a good image quality. I tried different papers, and different copy shops. What am I doing wrong please? Should I just redo everything with Photoshop or Indesign, would that change things?I have some vector graphics and fonts that I did myself and some photos processed with a filter by some apps, also 300 dpi I believe. What else can I do to get those pretty solid colors you see in commercial prints please? Thank you


Exclamatory questions and punctuation order

What is the punctuation order of question marks and exclamation points in exclamatory questions, e.g. How easy was that?  It could be How easy was that!?, or How easy was that?!  Are there any prescriptive rules for this(!?|?!) Or should I just do whatever I want?


I had used the Royer Oscillator topology (or a Mazzilli, are there significant differences ?) for a project on Induction heater. I had a hard time understanding how it actually works, especially how the two Mosfets trigger the oscillations. Somehow I ended up concluding that it has to do something with a tiny difference in the Q-points of the fets. Can anyone throw some light on this ? Thanks.  Edit: This is the version of the circuit I was referring to:   My actual doubt is whether the VI characteristics of the two transistors has a role to play, i.e, whether a tiny difference in their characteristics help one of the FETs to switch ON first and then on the switching alternates ?


C# Decimal conversion to float and insert into sql float column

I am having a hard time getting around this issue.   I am working with a enterprise DB table that has a column called balance which is a float.   I am trying to insert a decimal value into it. Now in c# I tried round the decimal to 2 places then inserting it into the column and it just does this. 56.4000015258789 when my value is 56.40.  I am debugging just before my insert and it is rounded. I can't change the column . . .so how do I get around this?   I know it has something to do with how sql considers fractions.   I tried formatting the decimal to a string then parsing it to a float and that didn't work.


Use multi ISO file in one Bootable CD/DVD

How can i have two or more ISO file that made for Boot (Bootable ISO), in One CD or DVD to boot ? I have two different anti-viruses (Live Rescue) and i want to use them in one CD or DVD and switch between them from a DOS Command-Line (That is on the CD/DVD). How can i do this ?


Using multiple variables over a single list in python (for loop)

I am working on a python script, which requires reading values from a list in for loop and performing some operations on it. currently it looks like this:  for i in someList:     # do some operation here   Now, this particular operation takes hours to complete, so what i want to be able to do is use multi-threading/sub-processes and process multiple items in parallel. So is there a way that I can run the for loop like:  for i,j,k in someList:     #do some operation here   i know this syntax can be used to iterate over multiple lists simultaneously, but I want to be able to use multiple items of the same list. What i want from the loop is that the value of i,j and k update in the following manner:  i = someList[1], j = someList[2], k = someList[3]   in the next iteration:  i = someList[4], j = someList[5], k = someList[6]


Where does the energy go when light is redshifted?

Imagine a galaxy millions of lightyears away and, obeying Hubble's law, moving very quickly away from us.   Now imagine the same galaxy emitted a green photon in our direction (a photon with a frequency of $f_g$.) That photon reached earth, due to the redshift, with a frequency $f_r$, with $f_g>f_r$. That means photon $f_g$ left the distant galaxy with an energy of $H_g=hf_g$, but when it reached Earth, it had an energy of $H_r=hf_r$.  But  $H_r < H_g$, so where did the difference between the energies go?


Not all TTF fonts visible from the (Sun) JDK

I wanted to use Monaco.ttf with IntelliJ. Unfortunately it doesn't show up.  I also noticed that the Monaco font doesn't appear in the list of fonts got from awt:  java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getAvailableFontFamilyNames()   I installed Monaco.ttf  in /usr/share/fonts/truetype/osx  I also tried to copy it in /usr/lib/jvm/java-6-sun/jre/lib/fonts and even tried to manually update the /usr/lib/jvm/java-6-sun/jre/lib/fonts/fonts.dir file  I restarted the jvm at each try, but the fonts is not visible from the sun jdk.  All other applications see that font (even eclipse, which is in java but uses the SWT library)  Does anybody know how to make jdk see additional fonts?


I have the following table. It contains multi-column headings.   I want the multi-column headings to be equally distributed in the available space. There is asymmetry now. The first two headings are too close and there is a space then the third one.   How can I adjust them to make equal width of the columns?  \documentclass{article}  \newcommand*{\zerobox}[2][l]{% \raisebox{0pt}[0pt][0pt]{\makebox[0pt][#1]{#2}} } \newcommand*{\anglelabel}[1]{% \multicolumn{1}{c}{\rotatebox{45}{\zerobox{#1}}}% } \newcommand*{\rotLabel}[1]{% \anglelabel{\zerobox{#1}} }  \usepackage{tikz} \usepackage{mathtools} \newcommand{\filledcirc}{${\color{black}\bullet}\mathllap{\circ}$} \newcommand{\normalcirc}{${\color{white}\bullet}\mathllap{\circ}$} \begin{document}   \begin{tabular}{ccc}  \rotLabel{Xxxxxxx} & \rotLabel{Ccccccccccccc} & \rotLabel{Rrrrrrrr Rrrrr}   \\ \hline \multicolumn{3}{|c|}{\textit{Ddddddddd Dddd}}\\ \hline \end{tabular}  \end{document}


I was surprised today to find out that the following appears to be valid code in Python:  def foo(n):   foo = n * 10   return foo  foo(5)   What in Python allows for a variable name to match the name of the function it is in? Is it just some kind of scoping rule that helps to keep these 2 things separate? so Python simply considers a program's function namespace to be a completely separate animal from the program's variable name space?  (Note: I would hate to do this in my own programs as it's a tad confusing but c'est la vie as they say in France.)


DRAM Frequency showing 800 instead of 1600

I am running a Core i7 CPU originally at 3Ghz overclocked to 4Ghz using a multiplier of x20 and a Bus Speed of 200 Mhz  My memory is 1600 Mhz OCZ.  I installed CPU-Z to see what is going on - but it shows me (under the "Memory" Tab):  DRAM Frequency 800 Mhz  Channel Triple - NB Frequency 3800.2 Mhz  So what is the actual frequency its running on then? I am slightly confused.


iOS Application development Certification

As we all know about the Microsoft Certified Professional Programs. I need to ask is there any institute offering online certification for iOS Professional Developer. I have visited , as it is offering a course but I could not get it that is it like MCP or not?