I'm beginner in C and I really need an efficient method to set all elements of an array equal zero or any same value. My array is too long, so I don't want to do it with for loop.
I have a large array in C (not C++ if that makes a difference). I want to initialize all members of the same value.  I could swear I once knew a simple way to do this. I could use memset() in my case, but isn't there a way to do this that is built right into the C syntax?
Tensor product of a sheaf of module and a residue field Let $S$ be a scheme over a finite field $\mathbb{F}_q$ and $\mathcal{L}$ an invertible sheaf on $S$.   In Pink's article (, see section 1.4 on page 13), he states that:  For any section $\ell\in \mathcal{L}(S)$ and any point $s\in S$ we let $\ell(s)\in \mathcal{L}\otimes_{\mathcal{O}_S}k(s)$ denote the value of $\ell$ over the residue field $k(s)$ of $s$.  My question is: what is the definition of $\mathcal{L}\otimes_{\mathcal{O}_S}k(s)$?  We know we can define the tensor product of two $A$-modules or of two $\mathcal{O}_X$-modules, but what is the tensor product of an $\mathcal{O}_X$-module and a field? I created a test MVC sharepoint app succesfully in a solution. Now I need to integrate this into a main solution project.   But when I added a SharePoint MVC App into the solution and hit F5, I am getting following error:  Error occurred in deployment step 'Install app for SharePoint':  Failed to install app for SharePoint. Please see the output window for details.   Detailed stack trace:  CorrelationId: 50583239-71cb-4b07-8bcb-4bbc51a22631      ErrorDetail: There was a problem with activating the app web definition.      ErrorType: App      ErrorTypeName: App Related      ExceptionMessage: Microsoft.SharePoint.SPException: Exception from HRESULT: 0x81070964 ---&gt; System.Runtime.InteropServices.COMException: Exception from HRESULT: 0x81070964 at Microsoft.SharePoint.Library.SPRequestInternalClass.EnableModuleFromXml(String bstrSetupDirectory, String bstrFeatureDirectory, String bstrUrl, String bstrXML, Boolean fForceUnghost, ISPEnableModuleCallback pModuleContext) at Microsoft.SharePoint.Library.SPRequest.EnableModuleFromXml(String bstrSetupDirectory, String bstrFeatureDirectory, String bstrUrl, String bstrXML, Boolean fForceUnghost, ISPEnableModuleCallback pModuleContext) --- End of inner exception stack trace --- at Microsoft.SharePoint.Administration.SPElementDefinitionCollection.ProvisionModules(SPFeaturePropertyCollection props, SPSite site, SPWeb web, SPFeatureActivateFlags activateFlags, Boolean fForce) at Microsoft.SharePoint.Administration.SPElementDefinitionCollection.ProvisionElements(SPFeaturePropertyCollection props, SPWebApplication webapp, SPSite site, SPWeb web, SPFeatureActivateFlags activateFlags, Boolean fForce) at Microsoft.SharePoint.SPFeature.Activate(SPSite siteParent, SPWeb webParent, SPFeaturePropertyCollection props, SPFeatureActivateFlags activateFlags, Boolean fForce) at Microsoft.SharePoint.SPFeatureCollection.AddInternal(SPFeatureDefinition featdef, Version version, SPFeaturePropertyCollection properties, SPFeatureActivateFlags activateFlags, Boolean force, Boolean fMarkOnly) at Microsoft.SharePoint.SPFeatureCollection.AddInternalWithName(Guid featureId, Int32 compatibilityLevel, String featureName, Version version, SPFeaturePropertyCollection properties, SPFeatureActivateFlags activateFlags, Boolean force, Boolean fMarkOnly, SPFeatureDefinitionScope featdefScope) at Microsoft.SharePoint.SPFeatureCollection.AddInternal(Guid featureId, Version version, SPFeaturePropertyCollection properties, Boolean force, Boolean fMarkOnly, SPFeatureDefinitionScope featdefScope) at Microsoft.SharePoint.SPFeatureCollection.Add(Guid featureId, Boolean force, SPFeatureDefinitionScope featdefScope) at Microsoft.SharePoint.SPUserSolutionCollection.EnsureWebFeaturesActivated(SPUserSolution solution) at Microsoft.SharePoint.Packaging.SPUserCodeSolutionDeploymentGroup.ActivateSolution(SPWeb web, SPUserSolution solution) at Microsoft.SharePoint.Packaging.SPUserCodeSolutionDeploymentGroup.Deploy() at Microsoft.SharePoint.Administration.SPAppTask.DeployOperation() at Microsoft.SharePoint.Lifecycle.MonitoredTaskExecution.DoTask()      Source: AppWeb      SourceName: App Web Deployment   Can somebody shed a light on this issue? :) Completeness and Incompleteness How to safely change OS name in grub boot menu? I have a system where I am dual-booting Ubuntu GNOME 15.10 and Ubuntu GNOME 16.04, however after installing Ubuntu GNOME 16.04, I have found that in the GRUB boot entry list it is called "Ubuntu", whereas the other one is called something like "Ubuntu GNOME 15.10", is there any way I can change the text of the "Ubuntu" one to "Ubuntu GNOME 16.04"? And also change the names of the other options so that instead of "Advanced options for Ubuntu" it says "Advanced options for Ubuntu GNOME 16.04" etc?  I rather do it manually if it is safe to do so, or a piece of software could be recommended, however nothing from a PPA or other untrusted not official source (I will only install software from the Ubuntu official repositories). You can use a standard dot notation or a method call in Objective-C to access a property of an object in Objective-C.  myObject.property = YES;   or  [myObject setProperty:YES];   Is there a difference in performance (in terms of accessing the property)? Is it just a matter of preference in terms of coding style? Why quantum mechanics? Imagine you're teaching a first course on quantum mechanics in which your students are well-versed in classical mechanics, but have never seen any quantum before.  How would you motivate the subject and convince your students that in fact classical mechanics cannot explain the real world and that quantum mechanics, given your knowledge of classical mechanics, is the most obvious alternative to try?  If you sit down and think about it, the idea that the state of a system, instead of being specified by the finitely many particles' position and momentum, is now described by an element of some abstract (rigged) Hilbert space and that the observables correspond to self-adjoint operators on the space of states is not at all obvious.  Why should this be the case, or at least, why might we expect this to be the case?   Then there is the issue of measurement which is even more difficult to motivate.  In the usual formulation of quantum mechanics, we assume that, given a state $|\psi \rangle$ and an observable $A$, the probability of measuring a value between $a$ and $a+da$ is given by $|\langle a|\psi \rangle |^2da$ (and furthermore, if $a$ is not an eigenvalue of $A$, then the probability of measuring a value in this interval is $0$).  How would you convince your students that this had to be the case?  I have thought about this question of motivation for a couple of years now, and so far, the only answers I've come up with are incomplete, not entirely satisfactory, and seem to be much more non-trivial than I feel they should be.  So, what do you guys think?  Can you motivate the usual formulation of quantum mechanics using only classical mechanics and minimal appeal to experimental results?  Note that, at some point, you will have to make reference to experiment.  After all, this is the reason why we needed to develop quantum mechanics.  In principle, we could just say "The Born Rule is true because its experimentally verified.", but I find this particularly unsatisfying.  I think we can do better.  Thus, I would ask that when you do invoke the results of an experiment, you do so to only justify fundamental truths, by which I mean something that can not itself just be explained in terms of more theory.  You might say that my conjecture is that the Born Rule is not a fundamental truth in this sense, but can instead be explained by more fundamental theory, which itself is justified via experiment.  Edit:  To clarify, I will try to make use of a much simpler example.  In an ideal gas, if you fix the volume, then the temperature is proportional to pressure.  So we may ask "Why?".  You could say "Well, because experiment.", or alternatively you could say "It is a trivial corollary of the ideal gas law.".  If you choose the latter, you can then ask why that is true.  Once again, you can just say "Because experiment." or you could try to prove it using more fundamental physical truths (using the kinetic theory of gases, for example).  The objective, then, is to come up with the most fundamental physical truths, prove everything else we know in terms of those, and then verify the fundamental physical truths via experiment.  And in this particular case, the objective is to do this with quantum mechanics. this works in viewport but not in render.  import bpy from math import *  def frame_handler(scene):     z = scene.objects['Lift'].location[2]     scene.objects['Text'].data.body = str(floor(z / 4.0) - 2)  bpy.app.handlers.frame_change_pre.clear() bpy.app.handlers.frame_change_pre.append(frame_handler)   How to get it working in render? I've read  and changed from "bpy.data.objects" to "scene.objects" as already seen in the script. What am I missing? Blender v. 2.81.16  Edit. Tried that depsgraph thing mentioned in comments and changed to frame_change_post:  import bpy from bpy.app.handlers import persistent from math import *  @persistent  # maybe not relevant but doesn't harm anything? def frame_handler(scene, depsgraph):     z = scene.objects['Lift'].evaluated_get(depsgraph).location[2]     scene.objects['Text'].data.body = str(floor(z / 4.0) - 2)  bpy.app.handlers.frame_change_pre.clear() bpy.app.handlers.frame_change_post.clear() bpy.app.handlers.frame_change_post.append(frame_handler)   Now the Text doesn't show up at all in rendered (but works in viewport). I recently installed Ubuntu 14.04, then I installed lamp-server and placed my webpages in /var/www directory, but when I opened localhost in the browser there was nothing. I think that happened because Zend updated Apache.  Whatever the reason may be, I want to know where to keep my php files so that I can access them from my browser. One of my columns is called from. I can't change the name because I didn't make it. Am I allowed to do something like SELECT from FROM TableName or is there a special syntax to avoid the SQL Server being confused? tl;dr  Due to the special nature of Meta and the high rate of "lost souls", should we try out the Ask a Question Wizard here on Meta Stack Exchange too?  General idea  In case anyone doesn't know yet, . It guides new users towards writing better questions.  I think that such a question wizard would be useful on Meta Stack Exchange too, for three main reasons:   . There are four types of questions on Meta, each represented by the different required tags: , ,  and . Especially bug reports can often be split into a certain structure (what's wrong, how to reproduce, why I think it's wrong, examples). The same holds true for feature requests. Such a structure is ideal for a question wizard. Quite a few users  and . While the Meta community is well prepared to deal with these posts quickly, they lead to an less-than-ideal first impression by the new users and they distract the community from more important issues. Site-specific questions are often off-topic. This  since nowhere is it hinted at in the help pages (and there are a lot of old, not-yet-closed SO-specific questions from a prior era of this site) and can lead to unnecessary drama. If we add an honeypot into the wizard to catch this case (and ideally redirect them to the proper meta site), we could prevent this.   As Sonic said, there's an  new users need to read and confirm. However this doesn't really prove effective right now and we might need to try stronger tools (e.g. question wizard).  Therefore I think that we should test the Ask Question Wizard here on Meta too.  Implementation details (help welcome)  I think the wizard should have six main entry points:   I want to discuss a specific post or action from any Stack Exchange site. (-> honeypot, redirects to the appropriate per-site meta) I have a question regarding the use of Stack Exchange sites (-> support mode) I think I found a bug while using the Stack Exchange sites  (-> bug mode) I have an idea for improving the Stack Exchange sites  (-> feature request mode) I have a discussion I want to start about Stack Exchange communities or their rules  (-> discussion mode) I have some other (e.g. programming) question  (-> honeypot, redirects to )   Coming from these choices, the user would either be redirected to a landing page explaining, why this is not the right community and offering some alternative choices or they would follow the guided assistant.  For 1. the user might be asked on which site the post/action is. Maybe the system could show the three sites where the user was recently active/has the highest reputation on.  support mode would ask the user for these details:   what do you want to achieve? what have you tried? what is your current problem?   bug mode would ask the user for these details:   bug description how to reproduce the problem why do you think that this is wrong? (possibly) examples   feature request mode would ask the user for these details:   what is your goal? how do you think could this be achieved? why will the community benefit from this change? (possibly) details   discussion mode would ask the user for these details:   which rule do you want to propose/clarify (optionally) examples/why is this rule required?   Note: the above implementation details probably require some revision. Feel free to edit/suggest improvements for both wording and details. Retrieve the position (X,Y) of an HTML element relative to the browser window I want to know how to get the X and Y position of HTML elements such as img and div in JavaScript relative to the browser window. p-value approach - clarify teacher's solution? So I have a question with my teacher's solution below and I'm confused about one of the steps in their solution. I would appreciate some clarification.  Two brands of coffee were compared. Two independent random samples of 50 people each were asked to taste either Brand A or Brand B coffee, and indicate whether they liked it or not. Eighty four percent of the people who tasted Brand A liked it; the analogous sample proportion for Brand B was ninety percent.   (A) At α = 0.01, is there a significant difference in the proportions of individuals who like the two coffees? Use the p-value approach.   So I circled in blue a step where I'm confused about in the teacher's solution. I don't understand why P(Z&lt;-0.89) = 0.2061.   On the z-score table -0.89 is equal to 0.1867 so shouldn't it be that value instead? where did 0.2061 come from? Is it possible that the teacher made an error or am I not understanding something? How to EFI install Ubuntu? On trying to install Ubuntu 12.10 Desktop amd64 to a desktop pc using a ga a75 ud4h motherboard (which is using an AMD 3870k APU with a new 1TB HDD) following the advice in the  and  have now got to grub option screen for EFI install. Booting live dvd in EFI mode gives &quot;Secure Boot is not enabled&quot; just before grub kernel option list shows.  If the option to &quot;Install Ubuntu&quot; or &quot;Try Ubuntu without installing&quot; is selected gives &quot;can not read cd/0&quot; and &quot;the kernel must be loaded first&quot; errors. Using DVD or USB installation media gives same results and there has never been at any point an UEFI entry in bios/firmware settings or boot device list/s. It might be helpful to say that have had an alternative non-linux OS installing EFI mode on this hardware giving a GPT installation automagically using USB installation media when the hdd space was completely unallocated space. The USB device was listed under hard drives in bios/firmware one time boot list and did not have an UEFI entry. i.e. it installed EFI although no EFI or UEFI entry was assigned to the device like what is shown in many tutorials regarding UEFI installs. The only constructive information regarding this question is found at  and  but can not work out the answer. Checking md5sum and sha256 checksums on downloaded .iso and used &quot;Check disk for defects&quot; to check burned .iso when booting DVD in BIOS mode. No errors found. &quot;Check disk for defects&quot; will not run (or any other options) when DVD booted in EFI mode. Due to trying different distributions as well as older and newer flavours of Ubuntu all giving similar results in that no options from grub option screen in EFI mode are bootable (if getting that far) as well as spending time searching Ubuntu Forums have come to conclusion the firmware on this system is hardcoded to handle Microsoft EFI files only. After installing Windows EFI mode here is a  and here is a link to a thread i started at  which may be helpful to others building a dual boot system. Installing BIOS mode and using Boot-Repair to install grub-efi is not a complete solution due to the inability of using installation media EFI mode for recovery and maintenance due to the &quot;you need to load kernel first&quot; and &quot;can not read cd/files&quot; errors as described when trying to boot installation media using EFI. Secure Boot is not an issue. Using msinfo32 from windows confirms Secure Boot is not supported on this hardware. How to edit kernel or load kernel for EFI install? = How to EFI install Ubuntu? PLEASE CONSIDER: This is not a dupe!  The linked question that is indicated to having a working answer does not have a working answer to &quot;###How to edit kernel or load kernel for EFI install? = How to EFI install Ubuntu?&quot; therefor the workaround of installing using BIOS then manually install grub-efi without renaming bootloaders which works to get Ubuntu booting using EFI or using boot-repair to do this (and many unnecessary &quot;fixes&quot; if recommended repair is not changed in advanced settings) also works.  This goes some way to confirming hardcoding of firmware is not stopping grub the boot manager seeing the vmlinuz.efi files in /casper on DVD.  I would like an answer to this so would like this question to be reopened. Fatal Error: Allowed Memory Size of 134217728 Bytes Exhausted (CodeIgniter + XML-RPC) I have a bunch of client point of sale (POS) systems that periodically send new sales data to one centralized database, which stores the data into one big database for report generation.  The client POS is based on PHPPOS, and I have implemented a module that uses the standard XML-RPC library to send sales data to the service. The server system is built on CodeIgniter, and uses the XML-RPC and XML-RPCS libraries for the webservice component. Whenever I send a lot of sales data (as little as 50 rows from the sales table, and individual rows from sales_items pertaining to each item within the sale) I get the following error:  Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 54 bytes)   128M is the default value in php.ini, but I assume that is a huge number to break. In fact, I have even tried setting this value to 1024M, and all it does is take a longer time to error out.  As for steps I've taken, I've tried disabling all processing on the server-side, and have rigged it to return a canned response regardless of the input. However, I believe the problem lies in the actual sending of the data. I've even tried disabling the maximum script execution time for PHP, and it still errors out. When should I make my players actually roll for stuff? I've tried to focus my group heavily on Role Playing, perhaps too well given some of my recent problems, which are Orthagonal, and linked mostly to provide historical context.        A lot of the answers to these questions revolve around "have off the rail's multiple angles" and "don't make people roll for information they must have". That seems well understood to me at this juncture, in fact I have been doing just that, and I think it's causing some other problems.  I have only rarely made people roll for anything (combat aside) anymore, unless it's absolutely non critical. I try to get the players to Role Play their investigations and give them information when they look in the right places, and their are multiple right places.  This results in skills, especially social/mental, being completely inessential, and players not gaining important information because they aren't poking around the right area at all, or asking people who aren't interested in talking to them because they're currently a bunch of random Joe's.  The players aren't stuck at this time, I'm just trying to get better and not have functionally dead scenes, that don't rely on the players to play "what is the GM thinking" nor do I want to just give them every answer.  The reality is, I'm not sure when to make them roll to find things out. what criteria? or other advice, can I use to decide that the players are better off making a Roll to move forward than to purely use Role Playing?  update This question focuses on the Social and to a lesser degree Mental aspects, as it's usually pretty easy to tell when a Physical Roll is needed, even out of combat. It's harder to tell when to make people roll for things they can talk their way through.  I'm playing World of Darkness 2nd Edition, but answers not specific to that are welcome. Assume I have a dataset for a supervised statistical classification task, e.g., via a Bayes' classifier. This dataset consists of 20 features and I want to boil it down to 2 features via dimensionality reduction techniques such as Principal Component Analysis (PCA) and/or Linear Discriminant Analysis (LDA).  Both techniques are projecting the data onto a smaller feature subspace: with PCA, I would find the directions (components) that maximize the variance in the dataset (without considering the class labels), and with LDA I would have the components that maximize the between-class separation.  Now, I am wondering if, how, and why these techniques can be combined and if it makes sense.  For example:   transforming the dataset via PCA and projecting it onto a new 2D subspace transforming (the already PCA-transformed) dataset via LDA for max. in-class separation   or    skipping the PCA step and using the top 2 components from a LDA.   or any other combination that makes sense. Should edits with only minor code improvements be accepted. As an example, I'm reviewing an edit that changes all double quotes to single quotes and renames a variable in some javascript. With the exception of the variable rename (which is not entirely necessary), the edit is frivolous. Should I accept on the merits of a debatable variable name change? VPN server on Google Compute Engine with OpenVPN Cardinality of order types in $\mathbb{N}$ Let be the next equivalence relation on $B= \{R \subseteq \mathbb{N}\times\mathbb{N} \ | \ R \ is \ a \ well-order \ on \  \mathbb{N}\}$ : $$"R \equiv R' \leftrightarrow \ (\mathbb{N},R) \cong (\mathbb{N},R') \ are \ well-ordering \ sets \  isomorphic" $$  Which is the cardinality of $B/\equiv$?  Firstly, we can notice that each well-ordering set is isomorphic to an ordinal $\alpha \ $such that $\alpha &lt; \aleph_{1}$, and so it is enough to count how many ordinals are isomorphic to a subset of $\mathbb{N}$. For example, if we consider $A$ the set of the even numbers and $B$ the set of odd numbers with the usual order relation, $A \oplus B$ is isomorphic to $\omega + \omega$. Another example could be: if we consider the order of $\mathbb{N}$ that we use in Sharkowski Theorem, that order is isomorphic to $ \omega^{2} + \omega$. Working with prime numbers we could build also $\omega^{n} \ \forall n \in \mathbb{N}$, and so $\omega^{\omega}$ and maybe something bigger. However, we know that each countable ordinal is isomorphic to a subset of $\mathbb{Q}$, but I bet that the same result is not true for $\mathbb{N}$ because it is "too small".  What can I do? To prove the limit of $\frac{x^2+2\cos x-2}{x\sin^3 x}$ at zero is $1/12$