The Blender Principled BSDF shader is missing in my node editor. I'm using the latest Blender version 2.79. Please help :)
I have blender 2.69 and I've been following a tutorial on how to make text.  The only problem is when I go to add a glossy shader in the node editor it does not exist. Neither does the shader category.
Is Bezout's lemma enough to confirm the GCD of a number. Is Bezout's lemma enough to confirm the GCD of a number?  So suppose we have $$ax+by=z$$ does this mean $$\gcd(a,b)=z$$ I want to set up a diary that compiles in two different orders: One is work by day, the other is work by project according to tags I give to the particular chunks of work I did each day.   For example, I write my diary as usual in work by day form:  2/2/15  -- bought a new screwdriver (tag: car maintainence)   -- scetched my plan for world domination (tag: world domination)  3/4/15  -- started studying physics (tag: world domination)  -- finished tax declaraction (tag: burocracy)   Compiling by project would yield tags as sections:  car maintainence    -- 2/2/15: bought a new screwdriver  world domination  -- 2/2/15: scetched my plan for world domination  -- 3/4/15: started studying physics  burocracy  -- 3/4/15: finished tax declaraction   I know this is pretty close to the literal programming paradigm the whole LaTex documentation follows: A code chunks in a document can be compiled to two different orders: For human understanding and for use by the machine. However, I want two human readable versions --say pdf-files-- as output. Is there some package that helps? What's the best way to find the inverse of datetime.isocalendar()? How do you compare two version Strings in Java? Is there a standard idiom for comparing version numbers?  I can't just use a straight String compareTo because I don't know yet what the maximum number of point releases there will be.  I need to compare the versions and have the following hold true:  1.0 &lt; 1.1 1.0.1 &lt; 1.1 1.9 &lt; 1.10 Hero who is against enhancements but has some himself What is average distance from center of square to some point? Why does rubbing feet against sheets create a spark? Sometimes when I'm in bed at night, I rub my feet against the sheets and light is created. What exactly is going on?     I'm familiar with static electricity, and the triboelectric effect (creating a charge by rubbing 2 insulators together), and electrostatic discharge (releasing charge by touching a grounded conductor).     I believe that all of that is what is at work here, but I'm slightly confused since in other cases, the triboelectric effect and electrostatic discharge seem to occur as two separate steps, with different substances involved, and here, the two effects seem to be occurring simultaneously, with the same substances.     Can someone help me with a step-by-step explanation of the dynamics of what is going on? Could someone please explain? I couldn't find anything on the internet, everything talks about how to go about it in some way, but nothing says exactly what it is.   Also, what is a fully trusted assembly and how do they differ from one another?  I have a MS certification exam and this is the only topic that I just don't understand.  EDIT: Thanks guys. Now I have a better understanding of security in .NET. I was able to pass my certification exam. Inverse Fourier transform of Gaussian I need to calculate the Inverse Fourier Transform of this Gaussian function:  $\frac{1}{\sqrt{2\pi}} exp(\frac{-k^2 \sigma^2}{2})$  where $\sigma &gt; 0$, namely I have to calculate the following integral: $\int{\frac{1}{\sqrt{2\pi}} \exp(\frac{-k^2 \sigma^2}{2})} \exp(ikx) dk$.  How can I do that? If I am not wrong (in which case please correct me) the result should be $\frac{1}{\sqrt{2\pi}\sigma}exp(\frac{-x^2}{2\sigma^2})$...but I don't know how to get there! Is it possible to run Drush without root? I run a Linux server that is administered by a friend of mine, and at the moment I work with Filezilla.  I've heard that Drush is a trivial installation: it seems to require no configuration and work out of the box.   However, it looks for configuration in several places:     Drush installation directory,  the home directory (as .drushrc.php),    root directory of a Drupal installation, and  site directory of a   Drupal installation.  Since the configuration files are just PHP   scripts, they can  contain any PHP code that you would like to have   executed on startup of Drush.  one could for instance call ini_set()   to set the value of a PHP configuration option.   and the configuration file /opt/drush/drushrc.php with following content:    # Allow Drush to use 128 MB of memory. Use -1 for no limit. ini_set('memory_limit', '128M');   I see this is necessary because PHP's default is too low, but I'm not sure if I need higher-level privileges because of it.  Do I have to have root-level permissions on the server, or am I able to work with Drush without them?   Update:  As far as i understand this, i only have to ask my admin to get some more privileges (permissions)Note according to BetaRides answer i need to have more than only the access-data that the FileZilla needs - that are provided for the filezilla! Guess so - but i don not need root-permissions.  btw - i have secure-shell-access (ssh2 access) guess that this is enough -With that i can setup a sftp-connection to the server with filezilla just lemme know - if i can use the exactly same data for the shell access (with the command line tool=?!= Singular values of the data matrix and eigenvalues of the covariance matrix Proving the convergence of $\sum\limits_{n=1}^{\infty}\frac{1}{1+z^n}$ for $|z| > 1$ A positive alternative to "smelling" to describe something with a pleasant odor When one hears that something smells, one would generally assume that it smells bad.   Isn't there a word which wouldn't bring to mind the idea of a bad odor? For example, how would you describe pot-pourri (assuming you like the smell of pot-pourri)? If possible, I would like an adjective, or a word that could takes the place of an adjective. Cannot downgrade wpa_supplicant to fix Wi-Fi connection to a corporate network (WPA2/PEAP with no CA certificate) in Ubuntu 18.04 I recently upgraded my Ubuntu from 16.04 to 18.04 (clean install, full wipe). Now I can no longer connect to the corporate network at my office (perhaps related to these bugs: , ). What proved to fix this issue in Ubuntu 16.04 is the answer to ; Downgrade wpa_supplicant to 2.1.  However, even with the linode repository, this fix can no longer be applied. There is no version for wpa_supplicant below 2.6 to the best of my knowledge for Ubuntu 18.04.  My question is this: How can I downgrade wpa_supplicant to 2.1 for Ubuntu 18.04?  Configuration needed for corporate the wifi connection:   Security: WPA &amp; WPA2 Enterprise Authentication: Protected EAP (PEAP) Checkbox No CA certificate required. Inner authentication: MSCHAPv2 I want a green for "correct answer" and a red for "wrong answer". My current choice is rgb(144, 238, 144) for the green and rgb(250, 128, 114) for the red. (See wikilearner.net/wiki for the colours in action.)  I have been told that these colors are very close in contrast, making it difficult for a person with red-green color-blindness. What would be a better choice? How does password salt help against a rainbow table attack? I'm having some trouble understanding the purpose of a salt to a password.  It's my understanding that the primary use is to hamper a rainbow table attack.  However, the methods I've seen to implement this don't seem to really make the problem harder.  I've seen many tutorials suggesting that the salt be used as the following:  $hash =  md5($salt.$password)   The reasoning being that the hash now maps not to the original password, but a combination of the password and the salt.  But say $salt=foo and $password=bar and $hash=3858f62230ac3c915f300c664312c63f.  Now somebody with a rainbow table could reverse the hash and come up with the input "foobar".  They could then try all combinations of passwords (f, fo, foo, ... oobar, obar, bar, ar, ar).  It might take a few more milliseconds to get the password, but not much else.  The other use I've seen is on my linux system.  In the /etc/shadow the hashed passwords are actually stored with the salt.  For example, a salt of "foo" and password of "bar" would hash to this: $1$foo$te5SBM.7C25fFDu6bIRbX1.  If a hacker somehow were able to get his hands on this file, I don't see what purpose the salt serves, since the reverse hash of te5SBM.7C25fFDu6bIRbX is known to contain "foo".  Thanks for any light anybody can shed on this.  EDIT:  Thanks for the help.  To summarize what I understand, the salt makes the hashed password more complex, thus making it much less likely to exist in a precomputed rainbow table.  What I misunderstood before was that I was assuming a rainbow table existed for ALL hashes. It's a well-known theorem (Corollary 8.10 in Lee Smooth) that given a smooth map of manifolds  $\phi:M\rightarrow N$ and a regular value $p\in N$ of $\phi$, the level set $\phi^{-1}(p)\subset M$ is a closed embedded submanifold. Is the converse true? That is, given an embedded submanifold $S\subset M$, is there necessarily a manifold $N$, smooth map $\phi:M\rightarrow N$, and regular value $p\in N$ of $\phi$ such that $S=\phi^{-1}(p)$?   Prop. 8.12 in Lee Smooth shows that this is true locally; specifically,     Let $S$ be a subset of a smooth $n$-manifold $M$. Then $S$ is an embedded $k$-submanifold of $M$ if and only if every point $p\in S$ has a neighborhood $U\subset M$ such that $U\cap S$ is a level set of a submersion $\phi:U\rightarrow\mathbb{R}^{n-k}$.   (and any level set of a submersion is of course the level set of a regular value). I feel like this is the kind of question where, if there is a counterexample, it probably is very simple, but I wasn't able to come up with one. How to insert page number in Beamer navigation symbols? How does conservation work in wormholes? My questions might seem naive as I haven't plunged into the mathematical descriptions, but wormholes are interesting even if I don't actually know them :)  First of all, is wormhole making two possible paths betwwen points (like the tunnel in most visualisations) or is it just making two points beside each other like in the game Portal? Of course, second case can be bent into a tunnel, but there would be nothing special about tunnel part and no preferred way to divide into "normal" and "tunnel" part of spacetime.  My main questions are these:   Is momentum conserved? Is kinetic energy conserved? How does potential energy work?   To elaborate... In the game Portal you can fall into floor and fly out of the wall or floor elsewhere with the same speed, but another direction (normal to the portal). So momentum is not conserved, but kinetic energy is. Is that how it would actually work? Where does the momentum go then?  And does it really allow you to increase your potential energy while retaining kinetic? It would seem fair to take away some kinetic energy if you are put in a region where you have more potential energy.  Either way is the change in energy non-continuous like in the game and discussion that's linked below? Or are there just more than one way to move through but the change in potential energy is smooth in any of those? That would mean more potential equilibrium points though...  Similar questions has been discussed , is it correct about how the falling guys gets a lot of energy (in form of a potential one) by draining it from the mouths? Why don't the zoom buttons work on my DSLR? I am a newbie to the new camera I just bought. It is a Nikon D5200 it has the original lens that came on the camera a 18-55 lens on it. My question is when I turn the lens to the 55 and then push the plus and minus buttons at the bottom of my camera to zoom in it appears to be zooming in and then I take the photo and the picture is not zoomed in at all.    I have a new Canon T3i and was able to take and capture zoomed in photos with the lens that came with the camera (EF-S 18-55mm) as well as a Canon zoom lens EF 75-300mm 1:4-5.6. Now when I zoom in with either lens and take a photo, when I review it, it shows original image before zooming. Is it a defect in the camera or inexperience of the operator?    (Two separate questions from separate users but with the same root cause.)