I'm trying to produce a linear regression model, but I only have 25 observations and 34 predictors.  I'm trying feature selection,  library(MASS) full.m &lt;- lm(fmla, data=mydata) fsel.m &lt;- step(full.m, direction = "both")   but I get this error,  Error in step(full.m, direction = "both") :    AIC is -infinity for this model, so 'step' cannot proceed   Well, then I tried PCA and factor analysis but I get this weird image from PCA.  r &lt;- prcomp(formula=pca.fmla, mydata, scale=FALSE)     In factor analysis,  f &lt;- factanal(x=pca.fmla, mydata, factors=2)   I get,  Error in solve.default(cv) :    system is computationally singular: reciprocal condition number = 1.09137e-18   Any help please?  EDIT: I can answer this.
I am trying to perform stepwise regression for variable selection in R.  In matlab, the stepwisefit function is able to work in n &lt; p problems. Trying to use step() for such problems i get the error message AIC is -infinity for this model, so 'step' cannot proceed. Is there a way to modify parameters so i can use step function?
Design a custom Beamer theme from scratch Foundational proof for Mersenne primes I know how to prove that, if $2^n-1$ is prime and $n&gt;1$, then $n$ is prime.  But how do we prove that, if $a^n-1$ is prime and $n&gt;1$, then $a$ must equal 2? Fixing geometry validity errors in QGIS 2? How to print fields value in views-view.html.twig in drupal 8 How to print fields value in views-view.html.twig I have created a views-view.html.twig file for my view slider_3. The template name is 'views-view--slider_3.html.twig' The view formatting is done by this template, but I need a field is come at begging position of the view:  &lt;div class="slider-3-main"&gt;{{ rows.required_field }} &lt;div{{ attributes.addClass(classes) }}&gt;   {{ title_prefix }}   {% if title %}     {{ title }}   {% endif %}   {{ title_suffix }}    How can be the field will written to display at {{ rows.required_field }} Join CSV file to shapefile I have an Samsung Galaxy S3 Neo.  Bus 002 Device 042: ID 04e8:6860 Samsung Electronics Co., Ltd GT-I9100 Phone [Galaxy S II], GT-I9300 Phone [Galaxy S III], GT-P7500 [Galaxy Tab 10.1]   The keyboard &amp; language setting is português.  I today installed Android Device Manager and to test it's functionality I locked the phone with the password: "abcd" (4 letters were required).  After entering the password and confirming with the "OK" button of my keyboard, the phone showed me that the password is wrong. "Senha incorreta".  I reset the password after some tries to "123456" and the phone reloaded the lock screen. Again the password showed up to be wrong. I also tried the alphabetic password: "abcdefg" - same error.  I changed the language of my Google account from German to Portuguese and reset the password to "123456" again and I tried to really reboot my phone and unlock the SIM card again. But anyways I can not get through my lock of the Android Device Manager.  I tried to enter the password 35 times wrong with hope to get a chance to authenticate with my Google Account login.  I also tried to connect the phone with adb but it does not show up in this state with:  adb devices   So what can I do to get access to my phone again? Which variables should I transform, center, and/or standardize in my data for Principal Component Analysis? I have multiple datasets that I am attempting to use principal component analysis (PCA) on in order to infer the underlying structure of the data.  I'm attempting to predict growth increment of conifers (the response which apparently needed to be cube root transformed for my original linear models).  My predictor variables include: continuous (some log-transformed like size-related variables, some compositional, and some traditionally scaled); binary; ordinal; and nominal (of which I'm pretty sure I can order with respect to site productivity).  I'm mostly attempting to make inferences because some of my previous models from linear regression have not produced significant terms corresponding to categories like health or climate and I feel that they should have.  I've read in Joliffe (2002) that I might want to leave my compositional data uncentered.  Forgive my naiveté, but I'm wondering if I should also do this for my binary data.  It also seems that I might not want to scale these since they're already on a 0 - 1 scale but I'm not sure.  After only using my continuous predictors (including compositional variables), it appears that a size principal component makes up the largest portion of the variability and Joliffe also mentions that one might want to attempt a "double-centering" of the log-transformed data if this is the case.  I don't know if this is even possible since the log-transformed data only makes up a small portion of my datasets.  Finally, I should ask if having such a combination of data types will complicate analysis so much that it will make inferences unreliable.  I am currently using R for this analysis.  Thank you. Can the Hubble constant be measured locally? The Hubble constant, which roughly gauges the extent to which space is being stretched, can be determined from astronomical measurements of galactic velocities (via redshifts) and positions (via standard candles) relative to us. Recently a value of 67.80 ± 0.77 (km/s)/Mpc was published. On the scale of 1 A.U. the value is small, but not infinitesimal by any means (I did the calculation a few months ago, and I think it came out to about 10 meters / year / A.U.). So, can you conceive of a measurement of the Hubble constant that does not rely on any extra-galactic observations?  I ask because, whatever the nature of the expansion described by the Hubble constant, it seems to be completely absent from sub-galactic scales. It is as though the energy of gravitational binding (planets), or for that matter electromagnetic binding (atoms) makes matter completely immune from the expansion of space. The basis for this claim is that if space were also pulling atoms apart, I would naively assume we should be able to measure this effect through modern spectroscopy. Given that we are told the majority of the universe is dark energy, responsible for accelerating the expansion, I wonder, how does this expansion manifest itself locally?   Any thoughts would be appreciated. Should I be offered the option to upgrade to 18.04.1? I understand that the first point release of Ubuntu 18.04, namely 18.04.1 is now available and that my system should now offer it as an update.  My current OS version is 16.04.5 LTS. In System Settings/Software and Updates I have set 'Notify me of a new Ubuntu version' to 'For long term support versions'. I have tried both the main server and the server for United Kingdom, neither offers an update when Software Updater is clicked or via the Ubuntu Software icon.  Can anyone please tell me why I don't get the option of updating to 18.04?  Edit:  I don't remember the details exactly, but I think that my last LTS point release update was offered automatically a lot sooner after the published release date than where we are now with 18.04.1.  Edit 10th August  It appears that there has been some problem with the update process and that it should be fixed next week, see:    Edit 14th August 18.04.1 LTS now available from UK server, 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? Balloons and lifting gases Hydrogen is the lightest element, so it's cable of lifting the most weight in out atmosphere (probably not the best terminology there, but you get the picture)  Would hot hydrogen (in the same sense as hot air) be able to lift even more mass? Would a higher or lower density of hydrogen in a ballon lift more? If you could have a balloon which had nothing in it (it was a vacuum inside) would that lift more than a hydrogen balloon?  Basically what are the physics to balloons and lifting?  (really not sure what to tag this, so if someone else could that'd be great) How can I display a short chapter name in the header and a long chapter name in the ToC? I am writing a book and one of my chapters has a very long title. As it can't be displayed correctly on the top of even pages, I provide a "short title name" via the   \chapter[short title]{long title}   command. But then, "short title" appears in the table of contents instead of the original/true/long one.  How can I have the "short title" in the header of even pages, and the "long title" in the ToC and in the "Title header"?  For reference, here is the code I use:  \documentclass[11pt,a4paper]{book} \begin{document} \tableofcontents  \chapter[Short title]{Very vey very very very very very very long title     i can't display in the header} Lorem ipsum dolor sit amet, consectetur adipiscing elit. \end{document} In the spirit of a  I would like to know if there's a basis for understanding why there  that have non-zero electric charge but zero spin?  Can such a quantum theory be written down and self-consistent? Do the current symmetries of our present QFTs not allow such a particle? I made a plot but it's not at all what I want. There are two things I'm having trouble with: 1.) The bars should be at the bottom, but there's a space between them and the x-axis. 2.) E1/E4, E2/E5 and E3/E6 should have the same color.  Here's a picture of how it is and how I want it below:   And here's my code:  \documentclass{standalone} \usepackage{pgfplots,pgfplotstable} \begin{document} \begin{tikzpicture} \begin{axis}[ symbolic x coords={E1, E4 (dyn.), E2, E5 (dyn.), E3, E6 (dyn.)}, xtick=data, width=\linewidth, height=6cm ] \addplot[ybar,fill=blue, bar width = 1cm] coordinates {     (E1,   8)     (E2,  15)     (E3,   50)     (E4 (dyn.), 4)     (E5 (dyn.), 17)     (E6 (dyn.), 40)  }; \end{axis} \end{tikzpicture} \end{document}   I hope you can help me. Thanks. Why is an untranslated string not showing up? In my module I have some custom strings. I use these in the t() function. When I go to admin/config/regional/translate/translate and filter the untranslated strings my custom strings do not show here.  What could be going wrong? I need to compile between two and four times before I see changes I make in the editor (TeXstudio) and each time I compile, a new .tex file is created with random letters and numbers at the end.   For example, If I create the file hello.tex and compile two to four times I'll get the file,   hello.tex.QU6664      then I make some small changes in the editor and compile two to four times I'll get the additional file,   hello.tex.Ak6664   After continuing to do this (each time compiling between two to four times before I see the changes I made), I now have many files that look like  hello.tex.QU6664, hello.tex.Ak6664, hello.tex.YX6664, hello.tex.sN6664, hello.tex.Ss6664, ...   A little bit of additional information (in case it's relevant): Everything was working fine up until a few days ago, i.e. only needed to compile once and only the file hello.tex was created. I still only get one .aux,  .synctex and .pdf files. I use TeXstudio to write and compile. I don't think it has anything to do with the bibliography (I tried removing bibliography altogether and still having the same problem).  How do I prevent these additional files from appearing and only compiling once like I used to? Has anyone had a similar problem? Java version problem with Eclipse and NetBeans on 18.04 How can I delete everything from my MacBook Pro before selling it? I have a Mac that runs Snow Leopard and I intend to upgrade it to Mountain Lion and sell it on ebay. However, I only have one hard-drive, and I'm sure I can't use something in my OS to delete my OS and all user data.  Is there something for this that's built into the firmware that I can do on boot, or otherwise?   I have source code on my Mac for multiple corporations' proprietary software and I can't risk somebody gaining access through the use of any sort of disk recovery tool. I plan to use a 7 pass erase rather than simply deleting the directory. If I reboot Ubuntu, then I need to log on each site and into Google Chrome account. What is the reason?  My system is Ubuntu 16.04 and Google Chrome 53.0.2785.101 (64-bit). UITextField - capture return button event