How to add a field to an existing model
Extending the User model with custom fields in Django
I have just updated MiKTeX and have found that pstricks now appears to cause a problem. The error message I'm getting is     ("C:\Program Files\MiKTeX 2.9\tex\generic\pstricks\pstricks.tex"      ! Undefined control sequence.      l.31 \if@check@engine   Not sure what's happening here. If I stop pstricks from being loaded things work ok.  Is there a known problem with the latest pstricks? Converting a pointer into an integer I am trying to adapt an existing code to a 64 bit machine. The main problem is that in one function, the previous coder uses a void* argument that is converted into suitable type in the function itself. A short example:  void function(MESSAGE_ID id, void* param) {     if(id == FOO) {         int real_param = (int)param;         // ...     } }   Of course, on a 64 bit machine, I get the error:  error: cast from 'void*' to 'int' loses precision   I would like to correct this so that it still works on a 32 bit machine and as cleanly as possible. Any idea ? What is the relationship between UV image and material texture? I am struggling to understand perhaps a very simple concept in Blender. There are materials which might have some diffuse coloring and a texture image, and there are also UV maps with their own images. Both can be applied to meshes or faces, but it seems that if a face has UV map then the material's texture is ignored and an image for UV map is picked.   If so, what is the use for a texture in a material if it is replaced by UV map's image?   EDIT: I've added some images to clarify the issue I have.   Case 1: a basic plane with material which has a texture, and no UV map. Diffuse color is applied, but material's texture is not.   Case 2: like above, but with reduced intensity of texture.   Case 3: Added UVmap and added image to the UVmap. Now I have texture, but not the diffuse color, and if UVmap was a different image, it would be picked regardless of texture set in the material.   So if I have UVmap image, what is the material texture for? How to select first occurrence between two patterns including them How can I select first occurrence between two patterns including them. Preferably using sed or awk.  I have:  text something P1 something content1 content2 something P2 something text something P1 something content3 content4 something P2 something text   I want the first occurrence of the lines between P1 and P2 (including P1 line and P2 line):  something P1 something content1 content2 something P2 something According to :     The electron has no known substructure. Hence, it is defined or assumed to be a point particle with a point charge and no spatial extent.   Does point particle mean the particle should not have a shape, surface area or volume?  But when I searched Google for the "electron shape" I got many results (like  and ) that says electrons are round in shape. What do I need to consider to choose between dSLR, mirrorless, or a compact as my first "serious" camera? I am thinking of buying a camera to learn photography. Most of the time I'll be shooting portraits and landscapes. But I am not sure where I should start. Most of my friends tell me that I should get an entry level DSLR, but I am not sure if I have the persistence and enthusiasm to carry it all day in a backpack. But the camera on my cellphone doesn't seem to be enough to begin with.  So what I want is some expert advice (preferably with professional experience). Can most compact fixed-lens or mirrorless cameras fit the situations I mentioned? Or do I really need to go to a DSLR to get a tool to learn photography? Best way to encode list names in sharepoint 2013 rest url's? If $\vec{a},\vec{b},\vec{c},\vec{d}$are unit vectors, $(\vec{a}\times\vec{b}).(\vec{c}\times\vec{d})=1$ and $\vec{a}.\vec{c}=\frac{1}{2}$,then If $\vec{a},\vec{b},\vec{c},\vec{d}$are unit vectors such that $(\vec{a}\times\vec{b}).(\vec{c}\times\vec{d})=1$ and $\vec{a}.\vec{c}=\frac{1}{2}$,then $(A)\vec{a},\vec{b},\vec{c}$ are non-coplanar $(B)\vec{a},\vec{b},\vec{d}$ are non-coplanar $(C)\vec{b},\vec{d}$ are non-parallel. $(D)\vec{a},\vec{d}$ are parallel and $\vec{b}$ and $\vec{c}$ are parallel.    My Attempt: $(\vec{a}\times\vec{b}).(\vec{c}\times\vec{d})=1$ $(\vec{a}.\vec{c})(\vec{b}.\vec{d})-(\vec{a}.\vec{d})(\vec{b}.\vec{c})=1$ $\frac{1}{2}(\vec{b}.\vec{d})-(\vec{a}.\vec{d})(\vec{b}.\vec{c})=1$    Book's Solution which i did not understand: $(\vec{a}\times\vec{b}).(\vec{c}\times\vec{d})=1$ is possible only when $|\vec{a}\times\vec{b}|=|\vec{c}\times\vec{d}|=0$ and $(\vec{a}\times\vec{b})$ is parallel to $(\vec{c}\times\vec{d})$ And the correct option given is $(C)$.  I could not solve this problem after some efforts.Please help me.Thanks. Hey guys I found one or two papers which use ridge regression (for basketball data). I was always told to standardize my variables if I ran a ridge regression, but I was simply told to do this because ridge was scale variant (ridge regression wasn't really part of our course, so our lecturer skimmed through it).  These papers I read didn't standardize their variables, which I found a bit surprising. They also ended up with large values of lambda (around the 2000-4000 level) via cross-validation, and I was told that this is due to not standardizing the variables.  How exactly does leaving the variable(s) unstandardised lead to high lambda values and also, what are the consequences of not standardizing the variables in general? Is it really such a big deal?  Any help is much appreciated. I am having trouble comprehending how anyone could come up with this formula:  $$F = \frac{GMm}{d^2}.$$   Could someone walk me through this? Any thoughts on a semidecadian badge for people with five years service and an average of N points per year? Given that Stack Overflow is close to its fifth birthday as a public site, has any thought been given to a 'semidecadian' badge for people who have:   been registered with the site five years (a semi-decade, hence the name), scored more than N points per year on average (where N might be 1000).   The idea behind 'average of N points per year' is to allow slow starters to gain the badge eventually, rather than ruling them out in year 1.  The details are obviously subject to tweaking.  This might be a gold badge (the platinum version would be the decadian badge, with a larger value of N required — and no-one eligible for another 5 years or so).  These would complement the current Yearling badge (which is silver). Find a plane that passes through a point and is perpendicular to 2 planes How to use a field value in Template.php What's the function of the "|" (pipe) operator? I have a Windows 7 64-bit installation on my current PC, and I want to move it to a new PC .. I do NOT have a problem with licensing, as the new system already has its own new Windows 7 license, which I intend to use.  I want to use my existing installation, because it has 3 years worth of installed office related software development software, which installing again could take weeks !  I'm assuming that I can use Windows 7's Backup and Restore feature to backup a system image to a network location, then restore that network stored system image on the new PC ?  Again, like I said, I don't have a WIndows 7 licensing issue, as both machines are corporate provided and come with their own licences. PHPUnit skips all tests How can I extract menthol powder from fresh mint/peppermint? Merging columns from two separate files Open maps which are not continuous What is an example of an open map $(0,1) \to \mathbb{R}$ which is not continuous? Is it even possible for one to exist? What about in higher dimensions? The simplest example I've been able to think of is the map $e^{1/z}$ from $\mathbb{C}$ to $\mathbb{C}$ (filled in to be $0$ at $0$). There must be a simpler example, using the usual Euclidean topology, right? Show/Hide function folding margin on Notepad++ Is it possible to get rid of the function folding margin on Notepad++? It seems like the sort of thing that should be in the prefs but I'm not seeing it anywhere.