Variable Selection I am using R/RStudio to code a regression (and to optimize the function) over 50+ different variables. For the optimization to work I need to fit a higher order function (I am not sure to what degree I will use).  My question is this: is there a way in R to choose the best variables?
Choosing the best model from among different "best" models How do you choose a model from among different models chosen by different methods (e.g. backwards or forwards selection)?  Also what is a parsimonious model?
Dependency is not satisfiable: libtiff4 when trying to install Lightworks on Ubuntu 14.04 I was trying to install Lightworks 11.5.1 (amd64) on Ubuntu 14.04(amd64) but there's a notice: Dependency is not satisfiable: libtiff4. Is there anyway to solve this dependency issue?  Thanks in advance. How can I use 3rd party libraries on QGIS plugins on Windows?   I've developed a plugin that uses rasterio and numpy for a customer, but he's having problems installing rasterio and numpy.  Actually rasterio and numpy were installed in it's main system Python (C:\Python27), but I need QGIS Python to recognize it. L293, L298 and SN754410 H-bridge drivers on low voltage power supply How to render an ASP.NET MVC view as a string? I want to output two different views (one as a string that will be sent as an email), and the other the page displayed to a user.  Is this possible in ASP.NET MVC beta?  I've tried multiple examples:  1.      If I use this example, I receive the "Cannot redirect after HTTP   headers have been sent.".   2.      If I use this, I seem to be unable to do a redirectToAction, as it   tries to render a view that may not exist. If I do return the view, it   is completely messed up and doesn't look right at all.   Does anyone have any ideas/solutions to these issues i have, or have any suggestions for better ones?  Many thanks!  Below is an example. What I'm trying to do is create the GetViewForEmail method:  public ActionResult OrderResult(string ref) {     //Get the order     Order order = OrderService.GetOrder(ref);      //The email helper would do the meat and veg by getting the view as a string     //Pass the control name (OrderResultEmail) and the model (order)     string emailView = GetViewForEmail("OrderResultEmail", order);      //Email the order out     EmailHelper(order, emailView);     return View("OrderResult", order); }   Accepted answer from Tim Scott (changed and formatted a little by me):  public virtual string RenderViewToString(     ControllerContext controllerContext,     string viewPath,     string masterPath,     ViewDataDictionary viewData,     TempDataDictionary tempData) {     Stream filter = null;     ViewPage viewPage = new ViewPage();      //Right, create our view     viewPage.ViewContext = new ViewContext(controllerContext, new WebFormView(viewPath, masterPath), viewData, tempData);      //Get the response context, flush it and get the response filter.     var response = viewPage.ViewContext.HttpContext.Response;     response.Flush();     var oldFilter = response.Filter;      try     {         //Put a new filter into the response         filter = new MemoryStream();         response.Filter = filter;          //Now render the view into the memorystream and flush the response         viewPage.ViewContext.View.Render(viewPage.ViewContext, viewPage.ViewContext.HttpContext.Response.Output);         response.Flush();          //Now read the rendered view.         filter.Position = 0;         var reader = new StreamReader(filter, response.ContentEncoding);         return reader.ReadToEnd();     }     finally     {         //Clean up.         if (filter != null)         {             filter.Dispose();         }          //Now replace the response filter         response.Filter = oldFilter;     } }   Example usage  Assuming a call from the controller to get the order confirmation email, passing the Site.Master location.  string myString = RenderViewToString(this.ControllerContext, "~/Views/Order/OrderResultEmail.aspx", "~/Views/Shared/Site.Master", this.ViewData, this.TempData); How do I add a DNS server via resolv.conf? Is /etc/resolv.conf useless in  (Precise Pangolin)?  I see that the DNS server information is stored in  now. The nmcli command line tool can list that for you.  If I want to add one more  server, will adding it to /etc/resolv.conf by using the resolvconf package help? Fuzzy string search library in Java Why light moves sideways? Greatings!  I'm trying to understand special relativity and have one question bugging me.  In almost every book or video about the subject there is a thought experiment with moving light clock. I hope I need not elaborate on the sutup and the outcome of the experiment.  So the question is this: When a light source on the MOVING light clock emits a photon of light the path of the photon is triangular.   How this can be?   I thought since light speed is constant in every reference frame the movment of the "emmiter" can't affect the movment of the light so light should shoot right up (from the point of stationary observer) and thus move backward and up from the point of moving observer.  So you see my logic is: light speed is invariant => you can't make it move UP &amp; FORWARD only UP. i.e. you can't change it's direction once it's emited in UP direction. Why the hell light moves sideways then?  And I'm puzzeled. There is flaw in the logic but I don't see it.  Thanks for help. Asymptotic expansion of $u_{n + 1} = \frac12 \arctan(u_n)$ Search for a string and print everything before and after within a range I have this file:  sometext1{ string1 }  sometext2{ string2 string3 }  sometext3{ string4 string5 string6 }   I want to search this file for a specific string and print everything before this string up to the opening { and everything after this string up to the closing }. I tried to achieve this with sed but if I try to print everything in the range /{/,/string2/ for example sed prints this:  sometext1{ string1 }  sometext2{ string2 sometext3{ string4 string5 string6 }   If I search for the string "string2" I need the output to be:   sometext2{ string2 string3 }   Thanks. If $z_n \to z$ then $(1+z_n/n)^n \to e^z$ We are dealing with $z \in \mathbb{C}$. I know that $$ \left(1+ \frac{z}{n} \right)^n \to e^{z} $$ as $n \to \infty$. So intuitively if $z_n \to z$ then we should have $$ \left(1+ \frac{z_n}{n} \right)^n \to e^{z}. $$ If $z_n \in \mathbb{R}$ I would be happy writing $$ \exp \left(n \log\left(1+ \frac{z_n}{n} \right) \right) = \exp \left(z_n \frac{\log\left(1+ \frac{z_n}{n} \right)-\log(1+0)}{\frac{z_n}{n}-0} \right) \to \exp(z \cdot 1) $$ where here we are using the definition of derivative. But if $z \in \mathbb{C}$ the logarithm is multivalued and I'm not sure that the same calculation is allowed. Is there a different way to show this for complex $z$? I've just been downvoted. How should I react? Why is gksu no longer installed by default? I have always recommended pressing ALT+F2 and typing for example gksu nautilus or gksudo nautilus both are equivalent; to run graphical programs with root privileges.  However, I have just installed raring on a test system and this no longer works.  gksu and gksudo are not installed as part of a default raring install; though they are in the repositories. In 12.04 at least gksudo was just a symbolic link to gksu  The reasons I have always done this are because while it is often safe to use sudo under some circumstances it can cause problems with graphical applications because gksu has you running the program as root while with sudo you are running as yourself but with elevated privileges.  This can mean you inadvertently change the owner of critical system files.  This can cause problems.  This reasoning is explained better here:         Why was command removed from a fresh install and what should we be using instead? multi-layer board copper pour I have a 6-layer board where the internal 4 planes are +15,GND,VCC,-15.  I was wondering if there was any advantage to doing a copper pour on the top and bottom layers?  I would probably leave them floating as I don't want to use micro-vias to say tie it to GND?    Is this actually a bad idea?  I.e. floating copper=antenna.  Would it be just as acceptable to have 4 layer board with the top layer having copper pour to VCC and the bottom having a pour to GND and keep the two internals as +-15?  Note that this is for a fairly low speed circuit which has some analog and digital parts. The roots of the equation $z^n=(1+z)^n$... The complex roots of the equation      $$z^{n}=(1+z)^{n}$$   $A.$ are vertices of a regular polygon  $B.$ lie on a circle  $C.$ are collinear  $D.$ none of these  Don't know where to start.. Please help.!  NOTE:  $z$ is a complex number. If I design a PC for use as an NPC, how much XP should he give when killed? As part of an early quest, my PCs are likely to face off against a wizard.  The problem here is that the stat block for Mage NPCs listed in the Basic Rules has a Challenge Rating of 6, while the PCs are going to be five Level 1s. So, instead of messing with the stat block and risk weakening it too much/too little, I'm choosing to create a Level 1 Wizard PC and use it as an NPC for this quest.  The problem with that is that, as far as I can tell, there aren't any designated rules for assigning either Challenge Ratings or XP values to a PC. So, should I just give the wizard a Challenge Rating equal to his level (and thus have him give 200 xp when killed), or is there a better way to do this?  (This is different from , because he's asking for a way to assign a level to an NPC, while I'm asking for a way to assign an XP value/Challenge Rating to a PC (for use as an NPC). Similar questions, but different.) How to disk copy with unreadable sectors? I want to clone a whole disk bytewise, something like  dd if=/dev/$SRC of=/dev/$DST bs=65536 count=$count   There are better tools for the job, which understand the file system (Windows) and work faster (I don't care), but they fail because of unreadable sectors on the old source disk.  There's actually a single invalid block I have to skip. So I thought about using dd multiple times like  dd if=/dev/$SRC of=/dev/$DST bs=65536 count=... dd if=/dev/zero of=/dev/$DST bs=65536 count=... skip=... seek=... dd if=/dev/$SRC of=/dev/$DST bs=65536 count=... skip=... seek=...   with replacing the broken sector data by zeros. Is this a valid approach? I found this  which confuses me. Why do I have to say “want you to do” instead of “want you do”? I'm confused about 'want you to do (something)' and 'want you do (something)'.  Example:      "I want you to eat fish" instead of "I want you eat fish" or "I want that you eat fish".    Can anyone explain what is the grammar rule for this? How do I get Gmail to ask me to be a mailto handler again? Equation parsing in Python How can I (easily) take a string such as "sin(x)*x^2" which might be entered by a user at runtime and produce a Python function that could be evaluated for any value of x? I've been having this issue for a while where I come to open the Terminal and I'm met with this:  Login incorrect login: _   I've already deleted the com.apple.terminal.plist to no avail. The really interesting thing is that sometimes it works, maybe 1 in 50 times. I literally have no idea what might be causing it and after searching the web for the better part of half a day it seems everyone else's issues are fixed when they delete the plist file.  How do I sort this out? I've tried running different shells (bash and zsh), but I still get this log in screen.  Also when I use Activity Monitor, I can see there is no shell running just the login.