I have a program I'm thinking through right now and doing tons of investigating on.  One of the stipulations with the program is that I want it so it can only run on Linux.  I DO NOT want the program to be usable on Windows or Apple...Linux only.  I have my reasons.  I know you can use certain modules(tkinter...root.mainloop()), ie, that will cause a program to not run in Windows if you leave certain things out.  Is there a way you can accomplish the same task without using any particular module...just 'base code'?


So I'm trying to build a laser bolt like in Star Wars, and I added a cylinder with an emission texture. The problem is, in Star Wars, the laser bolts have glare, so I added a glare node in the compositing tab. I rendered the image with the camera, and there was no difference.


A novel where a woman from "future" of 1999 speaks leet-speak

I'm trying to remember the name of a novel/series I read back in the mid-eighties.  I can't remember the author other than that it was a known older author.  I initially thought maybe Saberhagen or Harrison, but can't find it in their bibliographies.  It involved a collection of 4-5 people from different times/places.  The distinctive bit I can remember was that one of them (not the main character) was a cyberpunkish woman from the "future" of 1999 who spoke in futuristic dialect of English that the other characters, including the protagonist, from the "present" (from the eighties) could not understand.  Unfortunately, I don't remember much else of the plot other than that they were making their way through ruins.


How to slice a text file into several files of 100 lines each?

My question might be quite unclear here. I have a giant text file with values that looks like this  0.00601233 0.000139403 0.000133679 0.000139497 0.000141683 0.000141888 0.000138646 0.000133465 0.000146326 0.000135611 ...   And I want to slice it into several files of 100 lines.  File 1 will have lines 1 to 100.  File 2 will have lines 101 to 200.  etc...  There's probably a way to do this using sed or awk but I'm not familiar enough with theses tools or with regular expressions to do what I want here.


Movie where man is fastened on table and ants are eating/torturing him

As a kid, in the early 90s (maximum 91) or late 80s (87 till 89) I was in the cinema and saw some SciFi apocalyptic movie.  I only remember one scene when one man is fastened on some table and ants are eating/torturing him.   Does anybody have any idea the name of the movie?


I'm just going to get straight to the point  I recently just finished DMing a short campaign that hadn't gone as well as I hoped but people still seemed to enjoy themselves and want to play again!   As much as I do want to DM again I am slightly hesitant to play with certain players again due to them causing many issues that plagued the last campaign.  Such as Not paying attention, constantly talking over me when im trying to relay important information, and disrupting the game multiple times with dumb forced jokes like it was a Monty python sketch that forgot to be funny.  I have tried talking to them multiple times but they just don't listen to me. I have tried to be patient but Im fed up, I don't want to play with these people anymore but I don't know how to tell them this without them just continue to push me to let them join regardless or them feeling like Im being a killjoy.  How do I tell them I don't want them in the group without things getting to rocky.


Is it possible to link PDF files onto posts?

Let's say I have a PDF on my computer with information relating to my question that I cannot find elsewhere on the Internet.  Is it possible to link the PDF to a question or an answer I post on one of the Stack Exchange. network posts?


Novel about non modular aliens who die young

It's been years since I read it. So I'm not sure when the book was published but I read it sometime before 2006. It was a single novel. Not a series.  I remember that the protagonists - humans are travelling in space, encounter this planet with aliens. They slowly work with the aliens to learn the language and teach them human language.  The aliens finally let the humans come down to the planet. Towards the end of the book they realise these aliens can't have kids, they eat their young? They live very very short lives? This ties into the starting of the book since among the first set of aliens who made first contact there was one who died? Almost dying? And they switched her for someone else in order to keep up the pretext.   Ok another thing I remember is that the aliens think very differently from humans. While humans think abstractly and create modular components to build a complex system. The aliens create spaceships where parts play more than one role, if you destroy part of it, other parts take up that role.   They had cool weapons, romance I think? I read the book in India, but it's an English novel.


I don't know [who's responsible]. I don't know [who's the best person for this job]. I don't know [what's best].   I'm assuming sentences 1–3 are grammatical. How are the parts in brackets analyzed? I know in relative clauses subject–auxiliary inversion doesn't occur, unlike here, so these aren't relative clauses, are they? Are these "fused relatives" or "content clauses" or what? What would a modern analysis be? (I'm not asking for anything detailed here, just the general structure and the relevant terminology, essentially.) Related to the above:   I don't know who responsible is. I don't know who the best person for this job is. I don't know what best is.   Sentence 4 sounds weird/wrong, 5 sounds okay(?), and 6 sounds okay if you're asking about the word "best", I suppose. How come it's sometimes possible to transform the original sentences like this?


How do I specify the Linq OrderBy argument dynamically?

How do I specify the argument passed to orderby using a value I take as a parameter?  Ex:  List<Student> existingStudends = new List<Student>{ new Student {...}, new Student {...}}   Currently implementation:  List<Student> orderbyAddress = existingStudends.OrderBy(c => c.Address).ToList();   Instead of c.Address, how can I take that as a parameter?  Example    string param = "City";  List<Student> orderbyAddress = existingStudends.OrderByDescending(c => param).ToList();


Should one list incomplete degrees on a CV?

When applying for jobs after my PhD, should my CV include an incomplete degree I read towards years ago? It's a field completely unrelated to what I'm doing now. However, before my final year when I started getting sups and failures by the dozen (my reason for quitting) things actually went swimmingly. I worked with a renowned professor as an undergrad research assistant for a spell and even published a paper (on my own) during that phase of my academic journey. I didn't get a certificate out of it, but I nevertheless feel I honed some valuabe skills then (and of course I have a transcript listing the passes and failures).  I have since moved onto a completely unrelated humanities field. Should I mention the incomplete degree on my CV? If I ignore it, prospective employers might wonder what I did for three years of my life, surely? Should I list my science publication on my CV when it is irrelevant to what I'm doing now? Does quitting and switching tracks make me look flighty?


I am writing my thesis and using biblatex. The journal papers appear as:  H. Zhang and S. Wang. “Linearly constrained global optimization via piecewise- linear approximation”. In: Journal of Computational and  Applied Mathematics 214.1 (Apr. 2008), pp. 111–120.   However, I want the reference to appear as  H. Zhang and S. Wang. “Linearly constrained global optimization via piecewise- linear approximation”. In: Journal of Computational and  Applied Mathematics vol. 214 no. 1, pp. 111–120 April 2008.   Here is the compilable files    \documentclass[oneside,final, letterpaper, 12 pt]{ucr} \usepackage{setspace}   %%%%  for double sizing  \usepackage{subfigure} \usepackage{epsfig} \usepackage{amssymb,amsmath,color,graphicx, amsbsy} \usepackage{mathtools} \usepackage{algorithm} \usepackage{algorithmic} \usepackage{amsfonts} \usepackage{epstopdf} \usepackage{booktabs, multicol, multirow} \usepackage{pifont}% http://ctan.org/pkg/pifont \newcommand{\cmark}{\ding{51}}% \newcommand{\xmark}{\ding{55}}% \renewcommand{\tabcolsep}{.14cm}  \usepackage[style=numeric,         hyperref=true,         url=false,         isbn=false,         backref=false,         citereset=chapter,         maxcitenames=3,         maxbibnames=100,         block=none]{biblatex}   \DeclareFieldFormat[article]{volume}{vol.  #1} \DeclareFieldFormat[article]{number}{\addnbspace no.   #1}  \addbibresource{Bib_Files/Thesis_Bib_File.bib}  \DefineBibliographyStrings{english}{%  bibliography = {Bibliography}, }  \makeatletter \newcommand{\rmnum}[1]{\romannumeral #1} \newcommand{\Rmnum}[1]{\expandafter\@slowromancap\romannumeral #1@} \makeatother  \begin{document}  %%%%%%%%%%%%% For Double Spacing  \makeatletter \let\@currsize\normalsize \makeatother \setstretch{1.667} %%%%%%%%For Double Spacing    \title{Tile} \author{Author} \degreemonth{June} \degreeyear{Year} \degree{Degree}  \chair{Chair}  \maketitle \copyrightpage{} \approvalpage{}  \degreesemester{Spring}  \begin{frontmatter}  \begin{acknowledgements}   \end{acknowledgements}  \begin{dedication} \null\vfil {\large \begin{center} To my parents. \end{center}} \vfil\null \end{dedication}  \input{abstract}  \tableofcontents \listoffigures %\listoftables \end{frontmatter}  \begin{doublespace}  \graphicspath{{chapter1/}} \input{chapter1/ICC2012}  \graphicspath{{chapter2/}} \input{chapter2/ICC2012}  \graphicspath{{chapter3/}} \input{chapter3/proof}  \graphicspath{{chapter4/}} \input{chapter4/Risk_Managment}   \end{doublespace}   \begin{singlespace}  \printbibliography[heading=bibintoc]  \end{singlespace}   \end{document}


How to fix MySQL reinstallation failure in the Ubuntu 14.04 LTS?

I've tried removing and installing MySQL several times and I always get the same message:  Do you want to continue? [Y/n] Y Setting up mysql-server-5.5 (5.5.61-0ubuntu0.14.04.1) ... start: Job failed to start invoke-rc.d: initscript mysql, action "start" failed. dpkg: error processing package mysql-server-5.5 (--configure):  subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of mysql-server:  mysql-server depends on mysql-server-5.5; however:   Package mysql-server-5.5 is not configured yet.  dpkg: error processing package mysql-server (--configure):  dependency problems - leaving unconfigured No apport report written because the error message indicates its a followup error from a previous failure.                                       Errors were encountered while processing:  mysql-server-5.5  mysql-server E: Sub-process /usr/bin/dpkg returned an error code (1)     When I try to start the service, I get the following message:  Mysql command  root@falcon:~# mysql ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)   Mysqladmin command  root@falcon:~# sudo mysqladmin root root mysqladmin: connect to server at 'localhost' failed error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)' Check that mysqld is running and that the socket: '/var/run/mysqld/mysqld.sock' exists!   When listing the files in the "/var/run/mysqld" directory I realized that it is empty.  Mysql error log:  root@falcon:~# cat /var/log/mysql/error.log ERROR: 1005  Can't create table 'tmp_db' (errno: 13) 180916 22:22:50 [ERROR] Aborting  180916 22:22:50 [Note] /usr/sbin/mysqld: Shutdown complete  180916 22:22:50 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead. 180916 22:22:50 [Note] Plugin 'FEDERATED' is disabled. 180916 22:22:50 InnoDB: The InnoDB memory heap is disabled 180916 22:22:50 InnoDB: Mutexes and rw_locks use GCC atomic builtins 180916 22:22:50 InnoDB: Compressed tables use zlib 1.2.8 180916 22:22:50 InnoDB: Using Linux native AIO /usr/sbin/mysqld: Can't create/write to file '/tmp/ibr58D1n' (Errcode: 13) 180916 22:22:50  InnoDB: Error: unable to create temporary file; errno: 13 180916 22:22:50 [ERROR] Plugin 'InnoDB' init function returned error. 180916 22:22:50 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed. 180916 22:22:50 [ERROR] Unknown/unsupported storage engine: InnoDB 180916 22:22:50 [ERROR] Aborting  180916 22:22:50 [Note] /usr/sbin/mysqld: Shutdown complete   I have searched for this problem, but nothing worked for me. Please help.


I enabled Autologin during current installation of Ubuntu 18 Bionic Beaver.  I would like to Disable the AutoLogin but going to:  "Settings -> Details -> Users"  Doesn't give me the ability to turn the autologin off.  My last resort is to redo the installation without enabling it.


Is there any way of creating an array filled with a particular value in java?

My question is that, is there any way of creating a new array(any datatype) filled with a particular value as we can do in C/C++? eg :- int array[100] = {0};  I know, we can first create an array and then fill it with any value using java.util.Arrays, but I was asking if there was a single statement to do it like in C/C++


Mysql - get sum() result in another column

I get user_point column's sum like  select sum(user_point) as user_total_point from users;   but I also want to use that sum result for new generated column like  select sum(user_point) as user_total_point, (user_total_point * 100) as hundred_times from users;   -  Error: Query 1 ERROR: Unknown column 'user_total_point' in 'field list'   How can i use user_total_point column's value for another colums?


permutations with specified repetition counts

Problem: Determine the number of permutations of the characters for: AABBBC  How can I calculate a problem like this generally, given a set of characters and a number of times each has to appear?


If $f$ is nonnegative and continuous on $[a,b]$, then $\left(\int_a^b f(x)^n \ dx\right)^{1/n}\to\max\limits_{[a,b]} f$

I've been working on the following problem:      Show that if $f\in C[a, b]$ , $f\ge 0$ on $[a, b]$, then $\left(\int_a^b f(x)^n \,dx\right)^{1/n}$ converges when $n\to\infty$ and the limit is $\max_If$ with $I=[a, b]$.   This is my solution:  For  Weierstrass $f$ has maximum, $\exists \  \xi : f(\xi)=M$; and as $f$ is defined on $[a,b]$, $f$ is U.C., then:  $\forall \epsilon >0  \ \exists \delta >0: \forall x,y \in [a,b]: |x-y|< \delta \Rightarrow |f(x)-f(y)|< \epsilon$  Let $[a,b]=\bigcup_{k=1}^m I_k$, with $mis(I_k)<\delta$, and $M_k=max_{\bar(I_k)}  f(x)$ $(\int_a^b f(x)^n \  dx)^{1/n}=(\sum_{k=1}^m M_h^n mis(I_k))^{1/n}=(M_1^n mis(I_1)+...+M^n mis(I_j)+...M_m^n mis(I_m))^{1/n}=$ =$M ((M_1/M)^n mis(I_1)+...+mis(I_j)+...+(M_m/M)^n mis(I_m))^{1/n}$  Then:  $(\int_a^b f(x)^n \  dx)^{1/n} \ge M$  $(\int_a^b f(x)^n \  dx)^{1/n} \le M(b-a)^{1/n}$  $\Rightarrow \exists \  \lim_n \ (\int_a^b f(x)^n \  dx)^{1/n}=M=\max_I \ f$


How to interpret the significant interaction of two non-significant main predictors?

I have two non-significant main binary variables in my binary logistic regression model, but their interaction is significant. The variables are centered and no multicollinearity is the case (all VIFs about 1.0). The main variables are nonsignificant, but their interaction is. I want to interpret that significant interaction of two non-significant estimates.   It would read something like this: the effect of the variable A is less visible in the level 1 of the variable B (B1) and more visible in the second level of B (B2). Or I can say the same thing about the effect of B being less visible in A1 and more visible in A2...  However, the problem is that neither the effect of A, nor the effect of B are significant! So the above interpretation, although seemingly correct, sounds inconsistent or strange. (How a non-significant effect is supposed to be boosted by the other variable?)...   On a second thought, it seems that it is actually possible. For example, if I exclude cases with B2 from my sample, now the effect of A in the sample would show up as significant (it is B2 cases in the sample that disallow A to appear as significant)... This is getting more clear in my head now, but do you still have something other than the above interpretation in mind?


how to update information_schema.tables in mysql

i have a table A and i want to update the creation time of this table. I understand i cant simple update ( using update query) as it is not any table.  Is there any way i can update it.  for example creation time is '2015-07-03 12:03:33' to '2015-06-03 12:03:33'


Get record counts for all tables in MySQL database

Is there a way to get the count of rows in all tables in a MySQL database without running a SELECT count() on each table?


Who is the eponymous Jedi in Return of the Jedi?

I had always assumed the Jedi in the title of Return of the Jedi referred to Luke Skywalker's return from defeat. But Jedi is its own plural -- could it be referring to the rebuilding of the organization/movement/religion that presumably occurs after the Empire is defeated? Or maybe even to the return of Anakin's good side?  Yes, the title was originally Revenge of the Jedi, but that doesn't make it much clearer. It could still be either Luke's revenge, or the Jedi's revenge over the Sith, or even something else.  Did Lucas ever say exactly what it was he intended?


For a workflow tool I made a panel in which it displays each separate library that is linked in my file. For each library I want to add some buttons that does stuff to the library in question.  So in this example I have my panel which shows for example 2 libraries and for each one it creates a "reload" button.  Now my question is.. How do I make it so the reload button only reloads the library I want to reload? I would probably have to give the button an id or something so it knows for which library it was created...  my code so far:  import bpy  libs = bpy.data.libraries  class Reloadlib(bpy.types.Operator):     """Reloads the current Library"""     bl_idname = "my.reload_lib"     bl_label = "Reload"      def execute(self, context):         libs[?????].reload()         self.report({'INFO'}, 'Reloading ' + libs[?????].name)         return {'FINISHED'}  class LibPanel(bpy.types.Panel):     """Creates a Panel in the scene context of the properties editor"""     bl_label = "Scene Libraries"     bl_idname = "SCENE_PT_layout"     bl_space_type = 'PROPERTIES'     bl_region_type = 'WINDOW'     bl_context = "scene"      def draw(self, context):         layout = self.layout         scene = context.scene         layout.label(text="Libraries:")          for i in libs:             layout.label(text= i.name.replace(".blend",""))             row = layout.row()             sub = row.row()             sub.operator("my.reload_xref", icon = "FILE_REFRESH")  def register():     bpy.utils.register_class(Reloadlib)     bpy.utils.register_class(LibPanel)  def unregister():     bpy.utils.unregister_class(Reloadlib)     bpy.utils.unregister_class(LibPanel)  if __name__ == "__main__":     register()   Where the question marks are is where I should be able to make the difference between the first [0] or second [1] library in the libs[] array.  In future I would also like to ad an 'open' and an 'unlink' button for each library so I can make changes to the other file. But this works by the same principle as the reload button.


Is there an evolutionary advantage associated with migraine?

I have read  and I don't buy it     Because genetics influence susceptibility to migraine, it can be   shaped by evolution. Fitness-impairing disorders, including severe   headache, tend to disappear as a result of natural selection, and   their frequency decreases to near the rate of spontaneous   mutation. However, migraine has not   diminished over millions of years of evolution. Its prevalence has at   least been maintained at a high level, and has even been shown to be   increasing.   This phenomenon suggests that a central nervous system (CNS)   susceptible to severe, intermittent headache has been linked to an   important survival or reproductive advantage.   the argument in wiki is equivalent to since we know that evolution is correct - it means that headaches must benefit us somehow otherwise we wouldn't have it so let's think of some reasons - which is in my opinion is a fallacy.  I could believe that this is a bad side effect of some more efficient to survival trait like being smart, ()     Finally, migraine may be a component of imperfect central nervous   system design. Evidence has suggested a dysfunction of pain-inhibitory   pathways in migraine and discordant interaction between the ancient   brain stem design and the more evolved neocortex.   EDIT:  I have read the  and , and I agree that they do partially answer my question in regard that a mild 'badness' can get past. I would argue that my question is different in a way that I am referring to specific point The trait might have a tradeoff which essentially makes no change to the overall fitness  The way I understand it is that one gets some 'perk' that is beneficial in some situations and disadvantageous in others and they cancel each-other out. (I just don't see how without some huge benefit migraines would get past). What I am asking is what so advantageous we must have gotten - that such horrible thing like migraines got through.  Are there any studies done - that incapacitating migraines are coupled with an evolutionary trait?


I have a dual drive hard disk(SSD+ HDD) and my ubuntu is installed on SSD, can I install windows on the HDD?

I have a dual drive disk(SSD+ HDD) and my ubuntu(20.04) is installed on SSD, I've been trying to install windows 10 on the HDD (I made two partitions, and left 1TB unallocated), but everytime, windows get installed unsuccessfully I installed windows with making a Bootable USB with rufus and booted into it, and in the step of partitioning I used the 2TB HDD which i had formated GPT in ubuntu disks program, and separated a 460GB and a 540 and installed windows on the 420GB one, (I left 1 tb unallocated) (windows made a MSR partition itself too) after installation of windows 10 and booting the OS for the first time,  after getting services ready, it spends a long time on getting ready and then it goes to a blue screen saying a required device isn't connected or can't be accessed with error 0xc000000e. I tried solutions on the internet but the auto repair says that it couldn't repair the OS and when I type bootrec /scanos it says found 0 Windows installed What am I doing wrong?


How to paste text from an external source into the xterm edited file?

I want to copy some text from a webpage and paste it into a file opened with xterm editor. How can I paste my text into the xterm edited file?


If loss is decreasing but val_loss not, what is the problem and how can I fix it?  I get such vague result:


I am really annoyed by how little screen space is used for a question or actual content when I am not logged in to sites on the network.  I visited an AskUbuntu question and found less than 10% of the screen currently in view was what I actually wanted to see. With max resolution on my computer.    My view while looking at this page (and I'm sure many other people's view as well) is "I came here for answers to my question, not finding a Dream Job, not Signing Up and not joining a Developers Team."  I am posting this here rather than AskUbuntu Meta because most other sites (if not all of them) have the same clutter.      This needs to be fixed fast. Make the stuff a lot of viewers won't care about less intrusive.  If you have a look at my , you'll see how much I dislike distractions on these sites


What is the probability that random variable $x_1$ is maximum of random vector $X=(x_i)$ from a multivariate normal distribution?

Given a $n$-dimensional multivariate normal distribution $X=(x_i) \sim \mathcal{N}(\mu, \Sigma)$ with mean $\mu$ and covariance matrix $\Sigma$, what is the probability that $\forall j\in {1,\ldots,n}:x_1 \geq x_j$?


Travel to Spain with Norway residence permit

I am a student from Kosovo studying in Norway, and I have a residence permit. I want to know if I can travel to Spain for vacation.


I asked this question earlier , but was not clear which resulted in the question being closed, and was later told in the comments that I should ask the question again.  A requirement of my PHP/MySQL application is to allow all users to create their own multiple "views" of the data.  These views are not traditional SQL views, but performed by the application.  For instance, the user could create a view and provide the following criteria:   Name of the view. Desired records per page. Which columns to display by using a dropdown menu. Any filters for the results.  A first dropdown menu is used to select the column, a second dropdown menu is used to select the operator (equals, not equal, greater than, etc), and then either a third dropdown menu is used to select the value to be matched or the user directly enters the value to be matched. Whether the records should be grouped on a given column.   Based on the user's selection, various tables might need to be joined to the query to support the select, where, and group by clauses, and the application is used to eliminate duplicate table joins should they exist.  After the user has finished configuring their views, there is a dropdown menu which allows them to select their desired view, and the appropriate results are displayed.  I have implemented this functionality by storing the user's selections in several tables, and also storing the resultant query (actually, I store individual sections of the query in various columns so I may count the total results in an initial query and return the correct number of results in a second query) in a SQL table.  Note that I am storing the user's selections only so that I can allow them to edit their view requirements, and not to create the resultant query on the fly (more on this later).  I recognize that I have to be very careful as doing this can be prone to SQL injunction.  For instance, I can't just escape the user's input using PDO and store it in the database, and then later retrieve the data and use it in a query since when it is retrieved, it is no longer escaped.  To combat this risk, I limit user input to integers wherever possible, and typecast them where possible.  Where user inputs are percents and dollars, I multiply by 100, typecast the resultant as an integer, and then divide by 100 before storing it.  A couple of the filters require text as the value in the WHERE clause, and as stated earlier, escaping the data is not enought, and instead I am using $user_input= preg_replace('/[^a-z0-9,]/i', '', $_POST['user_input']); to make safe.  Is this an accepted method to implement this functionality?  Is there an easier way to ensure the user input is safe?  My earlier post  indicated that this type of practice should never be attempted, however, I don't know how else to do it.  Are there any other steps I should take to prevent injection?  Or maybe I should not create a query and store it in a table when the user saves his view configuration, but create the query on the fly using the user's saved values each time the user selects a given view.  This would have a negative performance impact and add complicity but I suppose I can do it.  Would you recommend using this strategy?  Thank you


Shapefile string data max length and character

Does anyone know why in ESRI help website (, ), it states that the field length if not specified will default to 255. However when I manually create a shapefile the max character is only 254. Why is there this difference of 1 character?


Choosing File Format of /home between NTFS and Ext4, Understanding Trade Offs in Performance vs Data sharing with WinXP in Dual boot

I have Win Xp on first Primary Partition.  I am leaving another 2 primaries for a future possible Win install. I am planning my Logical partitions to install a Linux Mint. I read that a separate /home gives re-usability across future Linus'es. I thought it might be clever to keep /home as NTFS, to smoothly share data across Win and Linux too. I am anxious though as most of the forums declare NTFS inferior to ext4. But some forums said that performance of file system is not as much driven by its structure, but mainly by the kernel driver and algorithms for read and write.   Questions   If Linux has good algorithms [as implemented with ext4], wont it perform same on NTFS too? May be the inferiority of NTFS is only with windows, But same NTFS performs equally well on ext4? If not, Is the peformance low enough to stay away from NTFS, and think of other ways to share data across Win and Linux? Does ways exist to read ext4 from WinXp or 7? Any other recommendations from practical experiences are welcome.


Can someone help me with the integral     $ \int_{0}^{1} \frac{x^2-1}{\log{x}} dx $   Tried substitution $ u = \log{x} $ but nothing came out. Thanks to helpers.


Defining a custom order in a Google Sheet query?

I'm using a Query in Google Sheets to pull data from another sheet. That query looks something like this:  =QUERY('Raw Data'!A2:AB,"SELECT E, A, C, D, Y, R, S WHERE S = 'New York'",1 )   What I'd like to do, though, is build a custom sort order within the function so that the Query automatically sorts by rows that have "string1" in column E, followed by those that have "string2" in column E, etc etc. The desired order is not alphabetical so I can't use a clause to sort in ascending or descending order.  I'd also prefer to do this without having to create another sheet where I rank my sort order in a table.


I have a .desktop file that contains these lines:  [Desktop Entry] Name=Firestorm Comment=Client for Online Virtual Worlds, such as Second Life Exec=/home/deus/Programs/Firestorm_64bit/firestorm Icon=/home/deus/Programs/Firestorm_64bit/firestorm_icon.png Terminal=false Type=Application TargetEnvironment=Unity StartupWMClass=do-not-directly-run-firestorm-bin Categories=Application;Network; StartupNotify=true   I just re-installed Ubuntu 14.04 before the reinstall this file worked just fine. Now it doesn't. I did set the exec property.  When I run it from terminal I get this:  deus@xxx:~/DesktopShortcuts$ ./firestorm.desktop  ./firestorm.desktop: line 1: [Desktop: command not found ./firestorm.desktop: line 3: for: command not found ./firestorm.desktop: line 10: Network: command not found   Can anyone tell me what the problem is and how to fix it?  Thank you.


Redirect video to virtual camera using v4l2loopback and ffmpeg

I have install v4l2loopback and ffmpeg. I want to stream/redirect a video to my virtual camera. How do I achieve this?


Can we add Top Questions to our careers page, just as we have Top Answers?

My  allows me to add Top Answers that I've posted on Stack Exchange.  This is great; it lets prospective employers see example of my knowledge and expertise, my style of solutions and helping others, etc.  Can we add the ability to also post Top Questions that we've asked, please?  Questions are just as valuable as answers.  No employer (should) expect to get an employee that knows everything. The way you address what you don't know, the kind of question you ask, the research or approaches you've taken to tackling a problem before you resort to asking others are all very useful information about the kind of employee someone will be.  In fact, putting on my interview hat for a moment, I would prefer to employ someone who knows less about an area but is intelligent when learning and tackling what they don't know, than someone who knows a lot but cannot handle problems.  There are a few questions of mine that I think show my approach to problem-solving, or my approach to ending ignorance, in a good light.  I'd like to showcase them!


How to determine if new hardware is compatible?

I am looking to purchase a new laptop but do not want to run Windows. In order to utilize both the new laptop and Ubuntu to their fullest, I want to verify that the hardware is fully compatable with the OS.  Is there a compatability matrix available that can be used to verify this? Does the hardware need to support open drivers or something similar?


Difference between Can/Could: "Can (could) you sell your old computer to me?"

What is difference between  Could you sell your old computer to me, seeing (that) you have no use for it. Can you sell your old computer to me, seeing (that) you have no use for it.  Can I use either one of them? Which one is grammatically correct or if both are, what is the difference in meaning?


Why should the equality of mixed partials be "intuitively obvious"?

I am reading Ted Shifrin's excellent book Multivariable Mathematics. It claims that the equality of mixed partials is "an intuitively obvious result, but the proof is quite subtle". However, I guess I must be thinking in the wrong way, because I do not see the intuition behind this result. This is how I think about it:  Let $f:\mathbb{R}^2 \to \mathbb{R}$. I think of $f_x$ as a "field of slopes" in the $x$-direction. If we analyze the movement in the $y$ direction in this field of slopes, we get $f_{xy}$. Now $f_y$ is a "field of slopes" in the $y$-direction. If we analyze movement in the $x$ direction here, we get $f_{yx}$.   It's unclear to me why movement in the $x$-direction in the "field of $y$-slopes" should be the same as movement in the $y$-direction in the "field of $x$-slopes".


Java: Multiple Loop Function Not returning

Given a polynomial, for example, 5x^4 - 1x^2 +2x^2 -3 +5x I create the following three arrays whose indexes match up with the variable,degree, and coefficient that each "item" in the polynomial has.  variableArray = [x,  , x, x, x] degreeArray   = [1, 1, 2, 2, 4]  //sorted on coefficentArray=[5, -3, 2, -1, 5]   I am attempting to write code that adds up all of the "items" with the same degrees and same variable, and returns a String of the new polynomial, so for instance what I'm looking for here would be 5x^4 + 1x^2 + 5x -3. Here is my function so far...      public static String putItTogether(int[] array,int[] array1, String[] array2, int count) {     int j = count; //count is number of items in arrays     StringBuilder builder = new StringBuilder();     for (int i=count; i<=0 ; i--) {          int answer = 0;          while (array[j] == array[j-1]) {                         //array = degrees //array1 = coefficients // array2 = variable               if (array2[j] == array2[j-1]) { //variable                     answer = array1[j] + array1[j-1];//coeff               }          j--;          }       String coefficientString = Integer.toString(answer);       String degreeString = Integer.toString(count);       builder.append(coefficientString);       if (array2[i].equals("x")) {           builder.append("x");       }       if (array[j] != 1) {          builder.append("^");          builder.append(degreeString);       }     }     return builder.toString(); }   The call...  String daAnswer = putItTogether(degreeArray, coefficientArray, variableArray, degreeCount);     System.out.println(daAnswer);   For whatever reason, it's not printing out anything. If you could look over my code, and see where I'm going wrong I'd really appreciate it. Also, any questions about what I'm asking please don't hesitate to ask!


What are the original TeX fonts installed on my computer?

I am trying to find the font I saw in some lecture notes. I think they are TeX native fonts but they might as well be fonts from Latex's packages? Please see attachment. Is there a place I can find the fonts that are native to TeX, by that I mean METAFONT?


Recover Fat32 which was wrongly formatted to Mac Journaled Disk

A Photocamera with default FAT32 formatted SD card was used and works in camera. It worked with Windows which can read and write the SD card. Someone plugged the card into Mac and formatted it to Mac extended journaled format.  But never wrote data on it.   Now the SD Card does not show any picture / JPG anymore in Mac. And Windows says "device needs to be formatted first". Is there any chance how to get most of the picture / data back?   For example format to FAT32 and try to undelete data by using special recovering tools.   Thanks for your experience


Create just one .tpl.php file for several nodes?

I created these .tpl.php file for two node:  html--node__39.tpl.php html--node__14.tpl.php  Question: can I create just one file for both node?, something like:  html--node__39&&14.tpl.php


Is power equal to $\vec{F}\cdot\vec{v}$ where $\vec{F}$ is force and $\vec{v}$ is velocity?

Can you please tell me when $P=\vec{F}\cdot\vec{v}$ is valid?  Let us consider $\vec{F}$ as to be a function of time $t$. We know that $P=\frac{dW}{dt}$, where $W$ stands for the work done.  $$P=\frac{d(F.x)}{dt}$$ and on should use the product rule for differentiation.  Is $P=\vec{F}\cdot\vec{v}$ not valid if the force is variable (i.e. a function of displacement or time)?


Segmentation fault pointer to a reference

I was trying out some code of Scott Meyers Effective C++, item 3 in particular.  The code in his book should be very similar to this (he left out the constructor)  #include <iostream>   class TextBlock { public:     TextBlock(char* ptr) : ptrText(ptr)     {}      char& operator[](std::size_t pos) const {         return ptrText[pos];     } private :     char* ptrText; };  int main(int argc, char* argv[]) {     const TextBlock block("Hello");     std::cout << block[0] << std::endl;     char* ptr = &block[0];     *ptr = 'J';     std::cout << block[0]; }   At the point where I change the contents in the pointer ptr (*ptr = 'J';), I get a segmentation fault (which normally happens when dereferencing an uninitialized or freed pointer).  This is not happening here, what is going wrong at *ptr = 'J';


What is so special about the principal value branch of inverse trigonometric functions.

Why only a specific branch of a inverse trigonometric functions is called principal value branch? For example in questions like  this- what will be the value of the function sin^-1(sinx), if x lies in certain branch? -we try to modify the concerned branch into principal branch and find the value of sin^-1(sinx). Why principal branch is so unique?


How to show that $ \sum_{k=1}^{2^n}\frac{1}{k}\geq 1+\frac{n}{2}$?

So in order to prove that the Harmonic series diverge, I want to show that: $$ \sum\limits_{k=1}^{2^n}\dfrac{1}{k}\geq 1+\dfrac{n}{2}$$ It is clear that if we expand the sum that this inequality holds true, $$n=3,\ \sum\limits_{k=1}^{2^3=8}\dfrac{1}{k}=1+\frac{1}{2}+\underbrace{\frac{1}{3}+\frac{1}{4}}\limits_{\geq \frac{1}{2}}+\underbrace{\frac{1}{5}+\frac{1}{6}+\frac{1}{7}+\frac{1}{8}}\limits_{\geq \frac{1}{2}}$$ but how can i show that using induction?  Any tips would be helpful, and thanks.


How to make a table on more than one page by using the table environment

EDIT Like some comments below are remarking the table environment doesn't allow tables over more than one page. However the solution works fine  I need to make a table over more than one page. The standard approach seems to be to use the ltablex environment. However, it doesn't work; also I assume that the table environment may also be required for the thesis template I work on (e.g. suppose for the capture).   \documentclass[11pt]{article} \usepackage{booktabs} \usepackage{tabularx} \usepackage{ltablex}  \begin{document}  \begin{table} \caption{Example of an table} \label{tab:daypack}      \begin{tabularx}{\linewidth}{@{}cX@{}}   \toprule \textbf{Column 1} & \textbf{Column 2} \\[6pt] \midrule \endhead $R$ & 1This is an example sentence \\[6pt] $R$ & 2As well as the line before \\[6pt] $A$ & 3Also this is an example \\[6pt] $R$ & 4This is an example sentence \\[6pt] $R$ & 5As well as the line before \\[6pt] $A$ & 6Also this is an example \\[6pt] $R$ & 7This is an example sentence \\[6pt] $R$ & 8As well as the line before \\[6pt] $A$ & 9Also this is an example \\[6pt] $R$ & 10This is an example sentence \\[6pt] $R$ & 11As well as the line before \\[6pt] $A$ & 12Also this is an example \\[6pt] $R$ & 13This is an example sentence \\[6pt] $R$ & 14As well as the line before \\[6pt] $A$ & 15Also this is an example \\[6pt] $R$ & 16This is an example sentence \\[6pt] $R$ & 17As well as the line before \\[6pt] $A$ & 18Also this is an example \\[6pt] $R$ & 19This is an example sentence \\[6pt] $R$ & 20As well as the line before \\[6pt] $A$ & 21Also this is an example \\[6pt] $R$ & 22This is an example sentence \\[6pt] $R$ & 23As well as the line before \\[6pt] $A$ & 24Also this is an example \\[6pt] $R$ & 25This is an example sentence \\[6pt] $R$ & 26As well as the line before \\[6pt] $A$ & 27Also this is an example \\[6pt] $R$ & 28This is an example sentence \\[6pt] $R$ & 29As well as the line before \\[6pt] $A$ & 30Also this is an example \\[6pt] $R$ & 31This is an example sentence \\[6pt] $R$ & 32As well as the line before \\[6pt] $A$ & 33Also this is an example \\[6pt] $R$ & 34This is an example sentence \\[6pt] $R$ & 35As well as the line before \\[6pt] $A$ & 36Also this is an example \\[6pt] $R$ & 37This is an example sentence \\[6pt] \bottomrule \end{tabularx}    \end{table}      \end{document}


What part of speech is "back" in "put the book back on the table"?

Put the book back on the table.   I'm having trouble. I think it is a preposition.


I have been trying to put side by side figures and have tried many options but couldn't get the success. I want to put 3 images as following attached image WITH CAPTIONS. If someone can help me, that would be awesome [I did try and search A LOT... Like REALLY A LOT]. Thanks.


How to delete personal stuff from laptop permanently!

I am selling my laptop with ubuntu OS. How can I make sure that I have deleted all my stuff from the laptop so the new use cannot access any of my stuff. I want to keep ubuntu OS though. Also I am asking I'm not very good with technology and any help will be appreciated!


Xpath in XML not working because of xml namespace field

I have the following XML:          <?xml version="1.0" encoding="UTF-8" ?> <bookstore xmlns="urn:hl7-org:v3" xmlns:voc="urn:hl7-org:v3/voc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:hl7-org:v3 PORT_MT020001.xsd" type="Observation" classCode="OBS" moodCode="EVN">     <book>         <title lang="en">Harry Potter</title>         <price>29.99</price>     </book>      <book>         <title lang="en">Learning XML</title>         <price>39.95</price>     </book> </bookstore>   When I try to use XMLDocument.SelectNodes() on the above xml like this:  XmlNodeList xmlNodelist = doc.SelectNodes("//book"); Console.WriteLine(xmlNodelist.Count);   I get a result of:   0   When I change the xmlns attribute value in root node to empty like this:  <bookstore xmlns="" ...........>   then I get back the proper result of:   2   Why is this happening? The xmlns attribute value in root node is vital to me. Is there any solution to this problem?


Polynomial $p(a) = 1$, why does it have at most 2 integer roots?

The question that I am trying to answer is :  Suppose is $p(x)$ is a polynomial with integer coefficients. Show that if $p(a) = 1$ for some integer a then $p(x)$ has at most two integer roots.  I have no idea how to get started. Any help would be awesome!


Find size of file names with space and hyphen | pass file names containing space and hyphen to "du"

I have a file, which contains the name of some files. I want to find the total size of files in the list.  #cat filelist /tmp-directory/connector_db_ connector_db /tmp-directory/connector_db -connector_db /tmp-directory/connector_db_connector_db   As you can see the names of the file contains space, and more badly a hyphen (-). I am trying to find the total size of these files with below command.  #du -sch `cat filelist` du: invalid option -- 'o' du: invalid option -- 'n' du: invalid option -- 'n' du: invalid option -- 'e' du: invalid option -- 't' du: invalid option -- 'o' du: invalid option -- 'r' du: invalid option -- '_' du: invalid maximum depth `b'   I tried adding " " as shown below and then tried which also failed  #cat filelist "/tmp-directory/connector_db_ connector_db" "/tmp-directory/connector_db -connector_db" "/tmp-directory/connector_db_connector_db"  #du -sch `cat filelist` du: invalid option -- 'o' du: invalid option -- 'n' .....   But this works when I use below command, directly in shell.  #du -sch "/tmp-directory/connector_db -connector_db" 0       /tmp-directory/connector_db -connector_db 0       total   So, how to handle such a situation. I have filelist of 3 lac files. More badly, "du -sch" is not handling the list when file list exceeds around 20000. I am splitting the list into 20000 lines with split command. Is there any alternate method for finding the size of 3 lac files easily?


mysql_real_escape_string() function for $user In PhP script, swears demanding to do how to fix it?

In this part requires to replace it:      $sql = "SELECT * FROM wallets WHERE id = '$user' LIMIT 1";   Requires to do this: use the mysql_real_escape_string() function for the $user parameter  How to implement it?  $sql = "SELECT * FROM wallets WHERE id = '$user' LIMIT 1";   Eliminate vulnerability!


Determining all the positive integers $n$ such that $n^4+n^3+n^2+n+1$ is a perfect square.

I successfully thought of bounding our expression examining consecutive squares that attain values close to it, and this led to the solution I'll post as an answer, which was the one reported. However, before that, I had briefly tried manipulating $$n^4+n^3+n^2+n+1=m^2.$$Since $n=1$ is not a solution, I rewrote this as $$\frac{n^5-1}{n-1}=m^2 \\ n^5-1=nm^2-m^2 \\ m^2-1=n(m^2-n^4) \\ (m-1)(m+1)=n(m-n^2)(m+n^2),$$ but in vain. Does manipulation lead somewhere? Is there a different approach from both of mine?


Really fix Win10 to prevent automatically adding keyboard layout

Yes, I see that , it is not the fix but just a workaround. That question has been closed for answer so I've to ask a "new" one. You can fix it if you copy your language preference to default user. Launch "Windows Settings" (press Ctrl+I) then go to "Time & Language" > "Language" > "Administrative language settings" > "Copy settings" (need the administrative privileges).


How can I determine what is taking up so much space?

I was using df -h to print out human readable disk usage. I would like to figure out what is taking up so much space. For instance, is there a way to pipe this command so that it prints out files that are larger than 1GB in size? Other ideas?  Thanks


I need to prove a limit on a closed interval $[0,1]$.   $f$ is integrable.  $$\lim_{n\to \infty}\int_0^1 x^n f(x) \, dx=0$$  Where should I start from?


Most powerful boy magician in the world is shown wonders by 4 men in trenchcoats

This is quite a recent book. It starts with a boy (as of yet unbeknownst the most powerful magician ever) who is offered to see the world of magic by four men in trenchcoats (one of them smokes).  He is shown many wonders.  He is taken in by a lady to a neutral Halloween party of good and evil and then ambushed.  He is then taken to a fairy dimension by one of these four men who turns into a lady as he crosses over.  He is told not to leave the path and is kidnapped by the Baba Yaga and he accepts a gift from the fairies preventing him from leaving their realm.


Update 1 - The suggested approach won't work, because of I need to load the whole Config, it's a contract between my code and external call (see my questions). The technique won't work at least because of Configuration is sealed.   I have and Xml string representing an entire config file as input and need to create an instance of System.Configuration.Configuration out of it for passing into an external routine, which performs:  ServiceModelSectionGroup.GetSectionGroup(configuration);   as part of its logic.  Wonder if it's possible to do it w/out using a file system (Can't call App domain for any direct manipulations neither).


How to stop others from downvoting my questions?

This is not the duplicate question. As in that question user got blocked. That is not the case               **with me. ** As I joined math.stackexchange I have asked two questions. I was new at that time and didn't know how to write a question. Those questions are not too bad.  Then someone with lots of reputation points advised me to edit my questions with what I had attempted. And I did that. But still one of my questions is on hold. That's not the problem. Problem is that people downvoting again and again without telling a proper reason. Is there a way to stop that?  Here are the links of those questions:


It is well known that a command like this:  cat filename | some_sed_command >filename   erases file filename, as the output redirection, being executed before the command, causes filename to be truncated.  One could solve the issue in the following way:  cat file | some_sed_command | tee file >/dev/null   but I'm not sure this would work in any case: what happens if file (and the result of the sed command) is very big? How can the operating system avoid to overwrite some content which is still not read? I see that there is also a sponge command which should work in any case: is it "safer" than tee?


I once have read a story about the spaceship and a device, than can produce anything, but only once in a lifetime.  Then, the spaceship encountered with an asteroid and crew start to fix it with all possible Mendeley's table elements.


I was wondering if the use of “for” like “because” was current use. For example: “I haven’t come to the party, for I was tired.” Is this used nowadays? Or shall we say “I haven’t come to the party because I was tired” otherwise? Thank you ever so much! 😊


If I am using align to display an equation and have each line numbered, how do I reset the align counter?  As is, even if I use \end{align} and later in the document have a second \begin{align}, the counter continues from where it left off, instead of starting at 1.  Is there any simple way to do this? Or would I be better off creating my own counter and not using align?  Edit: More specifically, I am this to show lines/steps on a solution to homework problems. Separate occurrences of (1) will be in answers to different problems, so there should not be any trouble distinguishing.


If Anakin brought balance to the Force, how could Kylo Ren be trained in the dark side?

In one of the prequels Yoda says to Obi-Wan after Anakin kills the “dark apprentice” there is always two a Sith and an apprentice. Only two no more no less. So fast forward to Darth Vader’s death. When Darth Vader kills the Sith Lord and in turn dies himself that should be the end of the “dark side”. So in retrospect where did the new Sith “big creepy hologram guy” come from?


Can my DS160 photo and the photo I take to my appointment be different?

The photo I uploaded online for DS160 is a little older than 6 months but shows no physical change to how I am now. But just in case, is it fine if I bring a more recent photo of me for the appointment rather than the same one I uploaded?


how to resolve the NullPointerException error in the following code? Throws error for setting text int TextField

public class Signup2 extends javax.swing.JFrame {  /**  * Creates new form Signup2  */ public Signup2() {     initComponents(); }  @SuppressWarnings("unchecked")   private void jTable1MouseClicked(java.awt.event.MouseEvent evt) {                                            int i=jTable1.getSelectedRow();     TableModel m=jTable1.getModel();     String reference_number;     reference_number=m.getValueAt(i,1).toString();     int no=0;     int n=0;String stm="";      try{         Class.forName("java.sql.DriverManager");         Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/google_email","root","root");         Statement st=con.createStatement();         String q="select message,subject from message where reference_num='"+reference_number+"';";         ResultSet rs=st.executeQuery(q);                 while(rs.next()){                   readmessage.jTextField1.setText(rs.getString("Subject"));                   readmessgae.jTextArea1.setText(rs.getString("message"));               }        }        catch(Exception e){          System.err.println(e);       }      dispose();    readmessage rm=new readmessage();    rm.setVisible(true);     }                                       readmessage is the name of the jFrame  There is an error in this code in jtable1MouseClicked event. Actually, it's throwing a NullPointerException in the code:  jTextField1.setText("subject");  jTextArea1.setText("message");   Instead of setting in a field or area I just printed it and it worked. What is the possible reason for the error and how can I solve it?   error:    java.lang.NullPointerException     at Signup2.jTable1MouseClicked(Signup2.java:182)     at Signup2.access$100(Signup2.java:19)     at Signup2$2.mouseClicked(Signup2.java:69)     at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:270)     at java.awt.Component.processMouseEvent(Component.java:6536)     at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)     at java.awt.Component.processEvent(Component.java:6298)     at java.awt.Container.processEvent(Container.java:2237)     at java.awt.Component.dispatchEventImpl(Component.java:4889)     at java.awt.Container.dispatchEventImpl(Container.java:2295)     at java.awt.Component.dispatchEvent(Component.java:4711)     at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4889)     at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4535)     at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4467)     at java.awt.Container.dispatchEventImpl(Container.java:2281)     at java.awt.Window.dispatchEventImpl(Window.java:2746)     at java.awt.Component.dispatchEvent(Component.java:4711)     at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)     at java.awt.EventQueue.access$500(EventQueue.java:97)     at java.awt.EventQueue$3.run(EventQueue.java:709)     at java.awt.EventQueue$3.run(EventQueue.java:703)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)     at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)     at java.awt.EventQueue$4.run(EventQueue.java:731)     at java.awt.EventQueue$4.run(EventQueue.java:729)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)     at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)     at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)     at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)     at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)


Proof of unit digit of $a^2$ Using Modular arithmetic.

We know whenever you square a given number $a$ The last digit of $a^2$ would be in the set :$$\{0,1,4,5,6,9\}$$ I didn’t quite understand the proof that was in my number theory book. I will present it here: $$10 \equiv 0 \mod 10 \implies a=\sum_{i=0}^{n} a_i 10^i \equiv a_o \mod 10$$ $$\implies a^2\equiv a_o^2 \mod 10$$ But $a_o \in \{0,1,2,3...9\} \implies a_o^2 \mod 10 \in \{0,1,4,5,6,9\}$. So the unit digit of $a^2$Is in the set $ \{0,1,4,5,6,9\} $ . My problem is in the first line because if you call a function $$f(x)=\sum_{i=0}^{n} a_i x^i \implies f(0)=0$$ So why did the book named $a_o$ instead of $0$


After running apt update I noticed that update info is being downloaded using HTTP.    After running upgrade, I see that upgrades are being downloaded from HTTP too.     My understanding is that HTTP is essentially insecure, i. e. open to intercept and replacement of data. Are the upgrades thus unsafe? Or do I misunderstand something?


ubuntu installing issue 16.04.1 on windows 10 HP laptop

Sir i want to remove win 10 and install ubuntu 16.04.1 but when i m installing it is showing "force UEFI installation?...this machine's firmware has started the installer in UEFI mode but it looks like there may exist operating systems already installed using "BIOS compatibility mode"...If you wish to install in UEFI mode and don't care about keeping the ability to boot one of the existing systems, you have the option to force that here......".  SIR TELL ANY PROCEDURE TO ITSTALL UBUNTU BUT I CAN INSTALL WINDOWS IN FUTURE AS WELL (SAFE METHOD) ?


Wavefunction, probability and impossible events

A friend of mine asked me a question, which I considered trivial at first, but after a while gave rise to some doubts.  For instance, we have a potential well in 1 dimension defined by $$ V(x)= \begin{cases} +\infty &\text{if}& x<0 \text{ and } x>L\\ 0 &\text{if} &0\leq x\leq L \end{cases} $$ We know the wave function that describes the particle in the potential at a given energy level $$ E_n=\frac{\hbar^2\pi^2n^2}{2mL^2} $$  Now if we take the state at the energy level $E_2$ we have a wavefunction that behaves like $\psi_2\sim\sin(\frac{2\pi x}{L})$. We are interested in the probability density, so we take the square modulus, which would be $0$ at $L/2$. According to this fact I would say that it's impossible to find the particle in the position $L/2$, which can be said as: the event: "find the particle at $L/2$" is impossible.  The problem is that probability tells me that the fact that the probability is zero doesn't mean that the event is impossible. Of course to get the probability I should integrate over a length, but how can I say that the event IS impossible? Isn't it?  Maybe it's a stupid question and I'm missing something, but I just can't fulfill my purpose.


How to measure the length of a string before a specific character

I'm calling an  which gives me the sunrise time of specific cities I request. The issue is that when the sunrise is before 10 am I get it in the format, for example, '9:10 am'. This messes up my code and I need it in the format '09:10 am'. I'm using UTC time depending on the location which is why it can give me time in am or pm. Is there a way to know the length of a string before a specific character, in this case ':'? Example string {"results":{"sunrise":"9:28:40 PM","sunset":"10:16:12 AM","solar_noon":"3:52:26 AM","day_length":"12:47:32","civil_twilight_begin":"9:05:59 PM","civil_twilight_end":"10:38:53 AM","nautical_twilight_begin":"8:39:14 PM","nautical_twilight_end":"11:05:38 AM","astronomical_twilight_begin":"8:12:02 PM","astronomical_twilight_end":"11:32:50 AM"},"status":"OK"}


Did the latest tax bill change how cost-basis are calculated when selling stocks?

When the tax bill was still pending, I recall reading somewhere that the bill changed capital gains tax so that instead of using the cost-basis for the stock in question you used a first-in first-out strategy so that the oldest cost-basis is the one use when selling.  I haven't been able to find anything that says whether this made it into the final law or not however. Does it still matter which stock you sell or is the cost basis used always the oldest under the new tax law?


lstlisting: how to set code color and frame color

I am using lstlisting to show some code in my PDF. The problem is that when I use:    basicstyle=\fontfamily{pcr}\selectfont\footnotesize\color{red},   to change the code color (not only the language keywords), the frame color changes too. What I want to achive is to have the source code all red and the frame black. Here my lstset:  \lstset{      language=C++, % choose the language of the code     basicstyle=\fontfamily{pcr}\selectfont\footnotesize\color{red},     keywordstyle=\color{black}\bfseries, % style for keywords     numbers=none, % where to put the line-numbers     numberstyle=\tiny, % the size of the fonts that are used for the line-numbers          backgroundcolor=\color{darkgray},     showspaces=false, % show spaces adding particular underscores     showstringspaces=false, % underline spaces within strings     showtabs=false, % show tabs within strings adding particular underscores     frame=single, % adds a frame around the code     tabsize=2, % sets default tabsize to 2 spaces     rulesepcolor=\color{gray}     captionpos=b, % sets the caption-position to bottom     breaklines=true, % sets automatic line breaking     breakatwhitespace=false,  }


Given an infinite set of cardinality $X$, is there a chain in $\mathcal P(X)$ of the same cardinalty of $\mathcal P(X)$?

$P(\mathbb N)$ = power set of $\mathbb N$. $A \subset P(\mathbb N)$ is a chain if $a,b \in A \implies$ either $a \subseteq b$ or $ b \subseteq a$ That is, we have something like this: $$\cdots a \subseteq b \subseteq c \subseteq\cdots$$ where $a,b,c \in A$ are distinct. We can show easy enough that there is an uncountable chain - this is done by noting $\mathbb N\sim\mathbb Q$ then using Dedekind cuts in $\mathbb Q$ to define $\mathbb R$ we see that a family of (nearly arbitrary) cuts satisfy the condition. For instance the family $L_r=\{q \in \mathbb Q : q < r \}$ for $r > 0$ gives us the sets we need and obviously we can pick others. I tried doing this for $ \mathbb R$ and don't seem to be getting anywhere.  To be more specific, does there exist a chain in $P(\mathbb R)$ with cardinality $2^ \mathbb R$? Given a set of cardinality $X$ (necessarily non-finite), is there a chain in $P(X)$ of the same cardinalty of $P(X)$?


Why does water fall sort of helically from a cup?

I noticed today that if I took a glass of water and poured it out slowly (small tilt to the cup), it flowed rather smoothly, but when I increased the tilt the water flowed in a sort of helical manner, this could be observed in the given image in the case of a tap:             What could the possible reason for such a flow be? Considering  (mentioned in comment), could it be that if speed of water flow be quick enough that the flow doesn't break down to form drops. This is what my limited non mathematical understanding brought me to.


This is what happens:  sudo apt-get install vlc Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package vlc   Please help. I would also like to know when this error occurs, I've seen it before too.


Is there a way to map an infinite grid onto the natural numbers efficiently?

I have a grid of cells that extends infinitely in all four directions. I need a way to map the coordinates of each cell to a unique positive integer efficiently. Can this be done non-sequentially? In other words, what is a function that is a bijection between $(\mathbb{Z},\mathbb{Z})$ and $(\mathbb{N})$?


Suppose that there is a man standing on the origin of the real line and plays heads or tails. Everytime he gets a head, he moves $1$ unit right and everytime he gets a tail, he moves $1$ unit left. What is the expected value of the number of his steps when he reached to $-7$ or $10$ for the first time? A friend of mine asked me this question today and my approach to solve it was quite complex. So any help is appreciated.


Is it correct that set ${\mathbb C}$ is isomorphic to the set of following 2x2 matrices: $$\left( \begin{array}{cc} a &-b\\ b &a  \end{array}\right) $$ $a \in {\mathbb R}$ and $b \in {\mathbb R} $?   In other words: are these two sets identical?


Minecraft "Unable to Connect to World" error - Mobile to Mobile (iOS)

I have been playing Mincraft with my son for last 10 months. We are both using iPad Pro's. And until recently we have had no problem connecting to each other worlds. Then about two months ago, suddenly we are no long able to connect to each other. We can still see each other. We can still start the join process on each others worlds. But every single time, we get the "Unable to connect to world" error. I have tried everything. I have rebooted the device. Swiped all of the apps out of memory. Signed out and back in again. Tried a third device. I checked the local network switch in settings. We are both on the same wifi network. I check the account settings at xbox live. I even deleted the game and reinstalled it. This is on a local network without any firewall or unusual router settings. Help!  Being stuck at home so much, we are really missing our favorite bonding experience. iOS 14.3, Minecraft v1.16.201


How to ask a user to answer to my question?

I have a question about a game library and there's a guy named  who has contributed to the library. He generally answers my question about the library. As I say I have a question but I don't know how to ask him to answer my question. Perhaps I just need to wait for a while until he find my question.


Laptop Lenovo G510 bluetooth doesn't work Ubuntu 14.04 LTS

i am totally new in Linux. I'm trying to find out how to get the bluetooth activated. I have searched so far in the web but no solution works. Please tell me what commands I should provide so you understand the problem. Thanks in advance!   these are the results:  fotis@fotis-Lenovo-G510:~$ lspci -knn | grep Net -A2 08:00.0 Network controller [0280]: Broadcom Corporation BCM43142 802.11b/g/n [14e4:4365] (rev 01)     Subsystem: Lenovo Device [17aa:0611]     Kernel driver in use: wl     Bus 001 Device 004: ID 105b:e065  fotis@fotis-Lenovo-G510:~$ uname -a Linux fotis-Lenovo-G510 3.19.0-33-generic #38~14.04.1-Ubuntu SMP Fri Nov 6 18:17:28 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux   modinfo btusb | grep -i 105b  does nothing  I tried this  but sometime it stops (probably needs different file).


Let $u$ be a distribution on $\mathbb{R}^n$ with support = $\left\{0\right\}$. Then there exists $N$ such that $u$ has order $N$. Let $\chi\in C_0^{\infty}(\mathbb{R}^n)$ a smooth function with  $\chi(x) = 1$ for $0\leq |x|\leq 1 $,   $\chi(x)\in [0,1]$ for $1\leq |x|\leq 2$,  $\chi(x)=0$ for $|x|\geq 2$  Denote $ \chi(x/r) = k_r(x)$ for $r\in (0,1]$. For the case $N=0$ I want to show that there exists $c_1$ such that $$|\left\langle u,\phi \right\rangle|\leq c_1 |\phi(0)|  $$ for all $\phi \in C_0^{\infty}(\mathbb{R}^n)$. The idea would be to apply $u$ on $\phi = k_r\phi+(1-k_r)\phi$ and letting $r\to 0$.   So then I guess we can write $$ |\left\langle u,\phi \right\rangle| \leq |\left\langle u,k_r\phi \right\rangle| + |\left\langle u,(1-k_r)\phi \right\rangle |$$ But not really sure how this follows...  Moreover how can i show that $\left\langle u,\phi \right\rangle = \left\langle u,\phi \chi\right\rangle = \left\langle u,\chi\right\rangle\phi(0) $?


Is there a way to rip audio DVD into 24bit AIFF or ALAC files on Ubuntu?


How do I determine the true pixel size of my Monitor in .NET?

I want to display an image at 'true size' in my application.  For that I need to know the pixel size of the display.  I know windows display resolution is nominally 96dpi, but for my purposes I want a better guess.  I understand this information may not always be available or accurate (e.g. older CRT displays), but I imagine with the prevelance of LCD displays that this should be possible!  Is there a way to get the pixel size of my display?  Is there a way to determine if the pixel size is accurate?  .NET API's preferred (I couldn't find them), but Win32 is OK too, I'm happy to P/Invoke.


I am using jQuery validation plugin for UI validation. I have a Jquery menu to select the type of transaction. On certain menu selection there should not be any validation happening. I am not sure if there is a way to tell Jquery validation to be disabled  I am using a following ways for the validation  1) $.validator.addMethod()  2) $.validator.addClassRules()  3) $("#submitButton").validate({     rules: { some rules },     messages: { some messages }  on click of the submit button for a particular menu selection i want the validation to be turned OFF. Is there a way to achieve this?


I've been creating a random element generator of my first text adventure game, to be more specific, this:      Random Generation = new Random();     List<Integer> interact = new ArrayList<Integer>();     for (int generator = Generation.nextInt(5) + 3; generator > 0; generator--) {         interact.add(Generation.nextInt(10));     };     System.out.println(interact);   Here, generator defines the amount of elements, and interact its a list that contains random numbers which represent different interactive objects, the thing is, i need elements don't repeat.  I was thinking in a int a = Generation.nextInt(3); if (a != interact[]) {interact.add(a)} else {generator++}; but I don't know how to set an [any] in comparing arrays.


What is the relationship between natbib, apacite package, and apa document class?

This is the first time I have to submit to a journal and need to reformat my bibliography according to APA guidelines.  This leaves me very confused since there seem to be multiple ways to do the same thing:   Use natbib and \bibliographystyle{apa} Use natbib and \bibliographystyle{apalike} Use package apacite. How is this different from natbib? Apparently I also need to specify \bibliographystyle{apacite} even though I have already loaded the package apacite. Plus, I can also load natbib through apacite!? The document class apa6. I understand that this formats the entire article, not just the bibliography. But as an option to this document class, I can load natbib as well?   I think my problem is that I'm only taught in simplistic terms, i.e. use natbib for your bibliography, without having a systematic understanding of how the process of creating a bibliography works. Could anyone please explain?


AngularJs gives WRONG result when multiply by 100

rank.js  $scope.ranks = [{id: 1, rank:1, cost:0.01, days: 3},     {id: 2, rank:2, cost:0.009, days: 3},     {id: 3, rank:3, cost:0.008, days: 3},     {id: 4, rank:4, cost:0.007, days: 3},     {id: 5, rank:5, cost:0.006, days: 3},     {id: 6, rank:6, cost:0.005, days: 3},     {id: 7, rank:7, cost:0.004, days: 3},     {id: 8, rank:8, cost:0.003, days: 3},     {id: 9, rank:9, cost:0.002, days: 3},     {id: 10, rank:10, cost:0.001, days: 3}     ]   rank.html

លេខរៀងទី {{rank.rank}} សេវា {{rank.cost * 100}}% = ${{100 * rank.cost}}

Rank Number {{rank.rank}} Fee {{rank.cost * 100}}% = ${{100 * rank.cost}}

កន្លែងមិនទំនេរ Not Available

   In Browser: rank.html   Why does rank number 2 and 4 produce wrong result? How can I fix it?   Thanks.


Allowing non-admins to run programs as admins

How can I enable non-admin users to run a certain application (in my case, a script) with admin permissions on Windows XP?  This would be similar to the setuid bit on *nix.


what are the various ways to define function in javascript

Which is is the  best way to define a function in javascript . how to define a function  using ':' like  function_Name : function(){} .


I am trying to add ECW support into Geoserver 2.1.1 (also tried 1.7.7) but no luck so far.  Does anyone have a step by step guide to add the ECW support ? (the one  However, my understanding is that Geoserver 2.1.1 uses imageio-ext that uses gdal-1.4.5  I am now lost between gdal version, geoserver version, imageio-ext version etc etc  This is what my gdal_native dir looks like  (where libecwj2.dll is copied from )


Can Altera GPIO pins read the input voltage?

I have ALtera DE2-115, and I have a light sensor module, the output of the light sensor is a voltage, how can I use the Altera GPIO pins to read the coming voltage? Thanks


Can't install Windows 8 while Ubuntu is already installed (want to dual boot)

I am using Ubuntu 12.04 LTS. I was trying to install Windows8 but at the partition selection I get this error "  We couldn't create a new partition or locate an existing partition   But I had installed windows several times from this media before and it worked fine. I think I am getting this error because I have Ubuntu 12.04 already. I want to dual boot with windows 8. How can I achieve that?


Protect SQL query from special characters

I'm trying to change the content of a string (from user's input), I'd like to remove any character that will let my query fail. For example, if I insert a second name with a " ' " in it, the query will fail.  Since I have to then output these rows from the DB, I'm wondering if there's any way to insert the string in the database while replacing the special character with its HTML value so that when I'm outputting it, the browser will do the rest.  I'm leaving you an example:  $string = $_POST['user_input']; // Let it be Lol'd $sql = "INSERT INTO table(field) VALUES('$string')";   Now without anything done to the string I'd get the query as:  INSERT INTO table(field) VALUES('Lol'd')  What I'm looking for is something to turn the ' into &#39; so that in the DB it's saved Lol&#39;d but when I echo it it'll just print Lol'd


What are the cases where one should avoid using a breadboard? e.g. high frequency, noise prone circuits etc.


Why does just splitting an Ethernet cable not work?

I thought the Ethernet is logically a one-line communication bus (for argument's sake, I am excluding hubs). All machines attached on the bus hears the same signals and the machines themselves try to avoid collisions by randomly backing off.    If so, why would splitting one Ethernet line from my home router into two and connecting two computers not work? Why do I have to add a switch to it?  What the Internet said would not work.                                                             +----------+                                                +---------->|computer 1|                                                |           +----------+     +------------------+       +---------------+     |4 port home router+------>|simple splitter|     +------------------+       +---------------+                                                |           +----------+                                                +---------->|computer 2|                                                            +----------+   What the Internet said I should do                                                             +----------+                                                +---------->|computer 1|                                                |           +----------+     +------------------+       +---------------+     |4 port home router+------>|    switch     |     +------------------+       +---------------+                                                |           +----------+                                                +---------->|computer 2|                                                            +----------+   Is this because of the signal degradation (reduced electric current)?    Thank you for all the answers! The reason why I did not just use the two ports of my home router is...  The 4-port gigabit router is in my room, and I had put a computer in another room (also my room, though). Since a wired network is far more reliable and secure, I had bought a long Ethernet cable and and connected the computer to the router. Now I was thinking about adding another computer to that room. I could buy another long Ethernet cable, but then there will be two cables between the rooms. The one line already is a minor annoyance, so I thought if I could share the one line between the two computers in that room. A switch would work, but it requires power and is a little bit pricey. That is why I wondered why it would not work to simply split the physical Ethernet cable.  Apparently I do not completely understand how Ethernet and a switch work. I just have some bit of knowledge I heard in my college class.


What's the use of C# keyword fixed/unsafe?  For example,   using System;  class Program {     unsafe static void Main()     {         fixed (char* value = "sam")         {             char* ptr = value;             while (*ptr != '\0')             {                 Console.WriteLine(*ptr);                 ++ptr;             }         }     } }   Why do I need to fix it in the first place? Thanks


I have 4 partitions in my hard drive  But when I install Ubuntu, it deletes all partitions and all data  Can I recover data? Please help...


What is the command to open the shutdown dialog?

I would like to use a gesture to shutdown/restart my computer and I need to know the command that launches the shutdown dialog:


Is it normal that there is an MS-DOS FAT32 partition in the hd not made by me?

Digging on my slowness my EtreCheck report.. report a 'sound me strange' MS-DOS partition  Disk Information: ⓘ     APPLE HDD HTS541010A9E662 disk0: (1 TB) (Rotational)     [Show SMART report]         EFI (disk0s1 - MS-DOS FAT32) <not mounted>  [EFI]: 210 MB          MacintoshHD (disk0s2 - Journaled HFS+) /  [Startup]: 999.35 GB (878.07 GB free)         Recovery HD (disk0s3 - Journaled HFS+) <not mounted>  [Recovery]: 650 MB   It is possible to know, maybe via terminal, when it was created and or from which process?  It could be that it has to do with an attempt to install bootcamp done time ago was not successful but then I formatted the disk so it is strange


Does anyone know any sources for free European city boundary data?


"Confirm you are ..." vs. "Confirm that you are ..."

In the example from the title, is it mandatory to use that?  The original sentence I picked up was from a checkbox marked     Confirm you are not a spammer   which I thought should be     Confirm that you are not a spammer   though I have seen a lot of usage without that after searching around.


Show $\frac{b}{c} + \frac{c}{a} + \frac{a}{b} \ge 3$ for $a,b,c > 0$.

Disclaimer: The statement may be false, but for now I'm operating under the assumption it's true and trying to prove it.   My workings:  I got a common denominator and expressed it as:  $$\frac{ab^2 + bc^2 + ca^2}{abc} \ge 3$$ $$ab^2 + bc^2 + ca^2 \ge 3abc$$  This is where I'm stuck. I feel as if I keep encountering this same result in various different problems and always am stumped on how to show it is true.   I tried to look at similar problems and it seems AM-GM inequality is the usual line of attack, so using that I reasoned, $$a^2 + b^2 + c^2 \ge 3abc$$, and now I need to establish $$ca^2 + ab^2 + bc^2 \ge a^2 + b^2 + c^2$$  However, this doesn't seem like it'd be true for general positive $a,b,c$.


There's been one problem I've had since I installed Ubuntu to run alongside Windows, I assume this would also be the same if it was installed to replace the other operating system as well, the installer prompts you to create a password upon typing in the user account name and if you don't put in a password and just put in the user account name, it ends up saying to create a password. My comparison is in Windows and Mac OS X, you are never forced to create a password.  If you remove the password on your Admin account in System Settings > User Accounts, you won't be able to authenticate whenever you try to install something, because it requests for a password and putting in no password at all isn't going to work, it will just act as if you put in an invalid password. This is what I call "getting locked out of privileges".  I'm finding the "Authenticate" window that comes up whenever you install something or accessing somewhere a nuisance, 'cause it always requests for your password.  So my question is - Why does Ubuntu force users to create a password upon installation?


Usage of passive forms without "be" verb

I will very grateful if you can help me understand the following issue:  As I understand, the next two sentences are interchangeable and have the same meaning:  1) Acts that are done by humans are not necessarily moral.  2) Acts done by humans are not necessarily moral.  The first option is a standard way of using the passive form of the verb. However, I don't understand why the second option is correct, If "done" this case as passive form of the verb or even if it can be treated as an adjective, I am expecting to see some tense of the "be" verb before.  There are many other similar examples, especially when using verbs like: "shown, suggested, presented, defined and etc." with a reference to a previous sentence of our article/text.  Thank you in advance.


RADEON HD 7670m drivers installation in 20.04 LTS

This GPU is not detected for proprietray drivers installation in Softwares & Update section. AMD has given the drivers only for 14.04.5 LTS and depends on xorg version of that time 1.1x also Linux kernel 4.4 Is there a way to rollback to that xorg version & use the same driver on 20.04 installation. A guide would be of great help.. Currently im using the iGPU Intel HD Graphics 4000 MESA GT2..// Radeon 7670m is shown & is inactive. i solved screen tearing with intel.conf file in xorg. I am also ok with using 14.04.6 LTS now without support, But a guide for setting all ppas or apt repo for getting most recent softwares with dependency restrictions..would be of great help.


No wireless for Intel Corporation 7260 version 63

I have a Dell XPS 12 running Ubuntu 13.10 and it doesn't appear to find it's wireless.  I have tried the suggestions  but they made no difference  peter@xps:/lib/firmware$ ls -l /lib/firmware/iwlwifi-7260-7.ucode  -rw-r--r-- 1 root root 682892 Aug  4 12:50 /lib/firmware/iwlwifi-7260-7.ucode peter@xps:/lib/firmware$ sudo lshw -c network   *-network UNCLAIMED             description: Network controller        product: Wireless 7260        vendor: Intel Corporation        physical id: 0        bus info: pci@0000:06:00.0        version: 63        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress cap_list        configuration: latency=0        resources: memory:f7c00000-f7c01fff  peter@xps:~/backports-3.10-2$ grep IWL7260_UCODE_API_MAX drivers/net/wireless/iwlwifi/iwl-7000.c  #define IWL7260_UCODE_API_MAX   7     .ucode_api_max = IWL7260_UCODE_API_MAX,         \ peter@xps:~/backports-3.10-2$ dmesg | grep iwl peter@xps:~/backports-3.10-2$ iwconfig lo        no wireless extensions.  peter@xps:~$ find / -name *7260-6* peter@xps:~$ find / -name *7260-7* /lib/firmware/iwlwifi-7260-7.ucode   peter@xps:~$ dmesg | grep -i -A 20 intel [ 1318.013278] Intel(R) Wireless WiFi driver for Linux, in-tree:d [ 1318.013281] Copyright(c) 2003-2013 Intel Corporation [ 1318.015154] cfg80211: World regulatory domain updated: [ 1318.015157] cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp) [ 1318.015159] cfg80211:   (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1318.015161] cfg80211:   (2457000 KHz - 2482000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1318.015162] cfg80211:   (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm) [ 1318.015164] cfg80211:   (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1318.015165] cfg80211:   (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)     What I have found is that it appears to be loading an old version of the firmware but I don't know how or why  peter@xps:/lib/firmware$ modinfo iwlwifi | grep 7260 firmware:       iwlwifi-7260-6.ucode peter@xps:/lib/firmware$ ls *7260-6* ls: cannot access *7260-6*: No such file or directory   Any suggestions of how to get this setup very welcome.


Show $\mathbb{Q}[\sqrt[3]{2}]$ is a field by rationalizing

I need to rationalize $\displaystyle\frac{1}{a+b\sqrt[3]2 + c(\sqrt[3]2)^2}$  I'm given what I need to rationalize it, namely $\displaystyle\frac{(a^2-2bc)+(-ab+2c^2)\sqrt[3]2+(b^2-ac)\sqrt[3]2^2}{(a^2-2bc)+(-ab+2c^2)\sqrt[3]2+(b^2-ac)\sqrt[3]2^2}$  But I fail to see the motivation behind this.  Can someone give a more general explanation of how to come to this expression?


Spaces in variable assignments in shell scripts

What is the difference between below variables assignments?   var=23 var =23 var= 23 var = 23   Is there any difference in space around the assignment operator?


how to hard-bypass the input of a line driver with a switch?

I want to use a balanced line driver of the type DRV134 or THAT1646. With a bypass switch I want to bypass the IC and send the signal to another circuit instead. In order to null the output of the driver IC in case the switch is in the bypass position, I thought of shunting the input to ground via 10k. Is this the correct way of handling this situation? Is it the correct resistor value? The driver source is an op-amp with no resistor or cap between them.         – Schematic created using   (the other pole of this switch switches the input of the other circuitry, respectively)


Last iteration of enhanced for loop in java

Is there a way to determine if the loop is iterating for the last time. My code looks something like this:  int[] array = {1, 2, 3...}; StringBuilder builder = new StringBuilder();  for(int i : array) {     builder.append("" + i);     if(!lastiteration)         builder.append(","); }   Now the thing is I don't want to append the comma in the last iteration. Now is there a way to determine if it is the last iteration or am I stuck with the for loop or using an external counter to keep track.


Passing variable number of arguments of different types in c

I want to make an function which will take variable number of arguments of different types. My problem is how can i parse the argument types. Like caller can pass arguments of any type in any order (without specifying format specifier). So at the calling function how can i differentiate between types.  How to print all values passed by the caller in the function var_argument ?   Let say I want to do sprintf inside var_argument function of the parameters passed by the caller  Here is my C code  #include <stdio.h> #include <stdarg.h> void var_argument(int num,...);  int main() {  var_argument(3,"Hello",7.87f,6);  var_argument(3,7.87f,"Hello",6);  return 0; }  void var_argument(int num,...) {  char str[80]; /* What code should I write to differentiate between types and to print all the values passed by the caller */        va_list list;  va_start(list,num);   /* How to do sprintf of the parameter passed to this function and store   the formatted output in the array str  */ }


How to clear Chocolatey cache in the free version?

Installation-file-cleaning is currently only available in  () and .  The package installation files can easily take gigabytes of storage space and to my knowledge they only increase in size as the user updates packages and installs new software, with only your hard drive capacity as the upper limit.   I don't know if Chocolatey stores cache in one central location — something is saved to ~\AppData\Local\Temp but the majority is located in the lib* folders in ~\ProgramData\chocolatey. Also the log files in the logs folder total to over 100 MB on my system. Is there any way to fully clear Chocolatey cache without manually deleting directories?


method overloading vs optional parameter in C# 4.0

which one is better? at a glance optional parameter seems better (less code, less XML documentation, etc), but why do most MSDN library classes use overloading instead of optional parameters?  Is there any special thing you have to take note when you choose to use optional parameter (or overloading)?


Simple property of a valuation on a field

Let $F$ be a field and $v:F\rightarrow G\cup\{\infty\}$ be a valuation on $F$ so $G$ is a totally ordered abelian group with $\infty$ having the properties $\infty+\infty=g+\infty=\infty+g=\infty$ and $\infty\leq\infty$ for all $g\in G$, $\infty \notin G$.     Show if $v(a)\neq v(b)$ then $v(a+b)=\min(v(a),v(b)$).   I must be missing some trick here on how to show this is true.  My approach has been to use that $G$ is a totally ordered group so I start by assuming $v(a)\neq v(b)$ and letting my first case be $v(a)<v(b)$ as trichotomy holds in $G$. By $v$ being a valuation on $F$, we then have that $v(a+b)\geq \min(v(a),v(b))=v(a)$. From here what I've tried doing doesn't seem to help much.  I've said lets assuming $v(a+b)>\min(v(a),v(b))=v(a)$ and we also have $$v(a+b)> v(a) \Rightarrow v(a+b)+v(a^{-1}) > 0 \Rightarrow v(1+ba^{-1}) > 0$$ and $$v(a)<v(b) \Rightarrow 0< v(b)+v(a^{-1}) \Rightarrow 0 < v(ba^{-1})$$ also $$v(1+ba^{-1})\geq\min(v(1),v(ba^{-1}))=\min(0,v(ba^{-1}))=0.$$  How does one solve this?


Proof that a formula $\theta$ is valid if and only if $\forall x \theta$ is valid

I need to prove for first-order logic that $\vDash\theta$ if and only if $\vDash\forall x \theta$. The proof for the forward direction seems simple enough:  Suppose $\theta$ is valid. Let $\mathfrak{A}$ be an arbitrary structure and let $s:V\to |\mathfrak{A}|$ be an arbitrary function assigning values of the universe of $\mathfrak{A}$ to variables. Then we know by assumption that $\vDash_\mathfrak{A}\theta[s]$.  But since $s$ is arbitrary, it follows that $\vDash_\mathfrak{A}\theta[s(x|c)]$, for all $c\in|\mathfrak{A}$. But this means that $\vDash_\mathfrak{A}\forall x\theta[s]$. Since $\mathfrak{A}$ and the function assigning elements of the structure to variables are arbitrary, it follows that $\vDash\forall x\theta$.   Now we have to show that if $\vDash\forall x\theta$, then $\vDash\theta$, and this is where I'm stuck. I understand why it makes sense that this should be true, I'm just having a hard time writing it rigorously. Any suggestions would be greatly appreciated.


Differences in vertical positioning of superscripts and subscripts depending on grouping (`{ }`): Why? Caveats? Workarounds?

drew my attention to the slightly different vertical positioning of super- and subscripts for such expressions. Compare (x+y)^8_8 (left) and {(x+y)}^8_8 (right) [all expressions in math mode]:    \documentclass{article} \begin{document} \((x+y)^8_8\), \({(x+y)}^8_8\) \end{document}   (This minimal example code is barely worth posting.)  This raises some questions for me:   Why is the vertical positioning different in the two expressions? Is there anything the LaTeX user should pay attention to to get such vertical positioning "right" (this is assuming that there is deeper rationale behind the difference)? Is there an easy way of getting such expressions to always have identical positioning of super- and subscripts?   The answers to the linked question above advise against the version with { }, so I assume that any rationale for the difference in vertical positioning will require a different example term.


How do I update Ruby Gems from behind a Proxy (ISA-NTLM)

The firewall I'm behind is running Microsoft ISA server in NTLM-only mode. Hash anyone have success getting their Ruby gems to install/update via Ruby SSPI gem or other method?  ... or am I just being lazy?  Note: rubysspi-1.2.4 does not work.  This also works for "igem", part of the IronRuby project


Is there a way to output a beamer presentation both with and without the "handout" option, in one run?

Each time I update my lecture slides I have to remember to compile the overlay version (for me to aid my presentation) as well as a handout version (for the students to print and take notes on). Right now, I manually add or remove the "handout" options, i.e. I use  \documentclass[handout]{beamer}   for handouts and   \documentclass[]{beamer}   for overlays.  Can I just get the LaTeX compiler to do both in one run?


Is there a way in Javascript to turn links in an HTML document into clickable links?

Is there a way in pure Javascript to turn links in an HTML document into clickable links? I do not want to use regex to solve this problem.  Let's say I have this list in an HTML5 doc:
 http://www.test.com http://www.example.com http://nicelink.com
   And I want it to automatically turn into this when the page is loaded:
 http://www.test.com http://www.example.com http://nicelink.com
   What would the vanilla JS code look like if I put a script in the header? Something looping through the HTML code and replacing the lines I suppose but I cannot write it in JS.  Signy


(update to 14.04) unity is not loading after I login to the admin profile after upgrade

After upgrading to 14.04 and after the final reboot, I logged in the admin account but unity won't start, I have only the 14.04 background.   No shortcuts work. I can login and use the guest and other accounts on the machine.   I think I might have opted to keep one of the settings that I was asked to select during the upgrade to 14.04.  What other info can I provide?  My chipset is Intel GM45 mobile.  Why does unity on the other accounts (guest, etc) login and work normally?  I have only been using ubuntu since 13.04, so im not that familiar with it. My setup is dual boot with windows 7 on a laptop. Can someone help?


Can you clone a larger drive onto a smaller drive (used space fits on the smaller)

I have a 500GB drive which is about 50GB full. I got a 80GB SSD, which has 74.5GB of available space. I want to clone the system drive onto the SSD.   DriveImage XML will not let me copy a larger drive to a smaller one.


Automorphism group of an abelian group abelian

Is the automorphism group of an abelian group abelian? If not is it true if either is finite? I cannot come up with a proof or an example.


What mechanics/objects are there in the D&D world to light fire. I'm thinking to literally light some kindling/flaming arrows etc.


What is the need for using active low inputs like EN' (read as "Enable bar") in digital electronic circuits?

Is there any special reason because of which active-low inputs are occasionally used instead of active-high inputs? Example: We have active-low inputs RD' (read as "READ bar") and WR' (read as "WRITE bar") for memory chips, instead we can have RD and WR as inputs right?


How to select multiple files with keyboard only in windows explorer

I know that we can use CtrlLeft Click to add a file to the selection in windows explorer. It is also possible to use ShiftArrow to extend the selction to adjacent files.  How can I select files that are not adjacent though - without using the mouse?  I noticed that I can use CtrlArrow to move some kind of cursor onto a file without actually selecting it, but then how can I select the file I want selected once that cursor is on it?  Bonus Points if you also know how to jump to a filename and add this to the selection, but that would be a different question


Last year I bought some Kreitler rollers and used them somewhat. The biggest problem I have is starting.   I have 4.5-Inch Kreitler Alloy Rollers with Killer Headwind Fan Drums.  Does anyone have a suggest on an easy way to start?


When do you omit a/an? - "Choose Suspect"

I was looking at an Android app, there are two buttons with these names: "Choose Suspect" and "Send Crime Report." After I thought about it, there are bunch of places where 'a/an' are omitted and they look just fine.  So, when is it safe to omit a/an? What's the mental model?  I checked  with similar title - "When do you omit a, an or the?" - which deals with omitting articles after 'of.'


WPF Add indentation before TreeViewItem template

I am developing a WPF application and I'm struggling with TreeView. I want to achieve look like in Windows Explorer.  The default TreeView style stretches the TreeViewItem only for the required space.  I have overridden the default template to achieve this look, but I really cannot figure out how to add the space on left of child items.  My code: <ControlTemplate TargetType="{x:Type TreeViewItem}">    <Grid>       <Grid.ColumnDefinitions>          <ColumnDefinition Width="*"/>       </Grid.ColumnDefinitions>       <Grid.RowDefinitions>          <RowDefinition Height="Auto"/>          <RowDefinition/>       </Grid.RowDefinitions>       <Border x:Name="Bd" Grid.Column="0" HorizontalAlignment="Stretch" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="true">          <Grid>             <Grid.ColumnDefinitions>                <ColumnDefinition MinWidth="19" Width="Auto"/>                <ColumnDefinition Width="*"/>             </Grid.ColumnDefinitions>             <Grid.RowDefinitions>                <RowDefinition Height="Auto"/>                <RowDefinition/>             </Grid.RowDefinitions>             <ContentPresenter x:Name="PART_Header" Grid.Column="1" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>             <ToggleButton x:Name="Expander" Grid.Column="0" ClickMode="Press" IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ExpandCollapseToggleStyle}"/>          </Grid>       </Border>       <ItemsPresenter x:Name="ItemsHost" Grid.Row="1" Grid.Column="1" />    </Grid>


I can't seem to get the reference within my {refsection}.  \documentclass[a4paper]{article}  \newcommand{\myparagraph}[1]{\paragraph{#1}\mbox{}\\}  \usepackage[     backend=bibtex,     isbn=false,     url=false,     doi=false,     eprint=false, ]{biblatex}  %Point to the bibliography db \addbibresource{mybib.bib}  \begin{document}  \include{myparagraph}  \end{document}   My paragraph file  \myparagraph{\fullcite{dante1320}} \begin{refsection}  \cite{manzoni1827}  \printbibliography[heading=subbibliography] \end{refsection}   I get the first citation (dante1320) right, but the second prints as [manzoni1827]. I don't get any error when I run Bibtex concerning the missing reference. But I got it when I run Latex: LaTeX Warning: Citation 'manzoni1827' on page 2 undefined on input line 5.