C++ Is it safe to test for NaN using cast to long?
Checking if a double (or float) is NaN in C++
Support for N-Gons (polygons consisting of more than 4 vertices) has been in Blender for a while now, but many of us still may not know when to use them, and how to do so effectively.  In what situations do N-Gons really come in handy? When should they be just plain left out? Do they have any place in finished models? Making Map Book of pages with same area shown but different layers turned on/off In ArcMap a Map Book is best suited for a series of features that each get their own page. It allows you to pick a feature and generate a Map Book Page for each feature including any additional information you wish to add to each page via dynamic text, charts, etc. Is there an alternative for say a series of pages showing the EXACT same area but with different layers turned on and off? We have a Capital Improvements document that I have to create showing the City Boundaries on every page. One page has all police and fire stations listed, another shows proposed water systems, another shows expressways and highways and work being done near or on them... etc., ad nauseum. Is there some way to set this up so that I DON'T have to created a separate MXD for each Map Page of this document? Should I be worried about electro-static discharge? Doing mostly micro-controller work, I have never bothered with grounding myself with a wrist-strap or any other implementation. Should I be worried about this? How serious is ESD when working at my workbench on projects? Idea behind proof that $\frac{21n+4}{14n+3}$ is irreducible for all $n$ I want to remove the URL that gets printed on the bottom of the page.   like:  yomari.com/.../main.php?sen_n   How can it be omitted or prevent from getting printed?  To be more specific, is there any way I can prevent the page URL, date and the page title being printed along, while printing the web page? Title page line spacing I have a simple problem but I didn't manage to find any answer for it. In my title page, I just used  \title{Name of the title}   then  \hrule height 0,1cm \leavevmode \\[0,5cm]     {\Huge{\textbf{\@title}}}\\[0,5cm] \hrule height 0,1cm \leavevmode \\[0,5cm]   to print the title of my document. But it takes more than 3 lines on the PDF file, and I have a different spacing between the 1st and 2nd line compared to the 2nd and 3rd, which is a bit frustrating.   Anyone got an idea of why ? How do you make USB bootable on chromebook I have a chromebook series 5. I want to install Ubuntu onto a USB stick. When I downloaded Ubuntu onto my USB stick, it won't start up.  Do I first have to download Ubuntu onto my chromebook hard drive, open Ubuntu and then make USB stick bootable? And then return back to chrome?  Or is there a way to download directly onto USB and make the stick bootable?  I appreciate any help. The bar at the very bottom of the screen has gone away? Install Alongside Windows or Something Else - Which should I use? I have old notebook with BIOS (not EFI) installed with Windows 8 RTM, want to install Ubuntu 12.10 by booting to a LiveCD.   Doing some research, I found method either to choose Something Else or Install Alongside... Which method should I use? Gerund preceded by a genitive? Is this sentence actually grammatical?     You know your having a rough day when kittens don't even make you smile.   The writer of this sentence may intend to mean you're instead of your but I'm just wondering if having a gerund preceded by a genitive is considered grammatical in this case.  If the sentence above is ungrammatical, why is this sentence grammatical?      He resents your being more popular than he is.   What's the difference between these two sentence that determines one to be grammatical and the other to be not?  This is how I analyze the two sentences and I can't see the difference:   "You know it when kittens don't even make you smile" for "it" = "your having a rough day" "He resents it" for "it" = "your being more popular than he is" I have just bought a Nikon 50mm f/1.8D prime lens.  I took this picture (leg of my glasses frame on a mouse, and a LED desk lamp is on top of it) : f1.8, 1/80s, ISO 200   The purple fringing is right in the middle of the picture. Does it happen very often to this lens? Programmatically delete one entry from one field on one entity What's the proper way to programmatically delete one specific field entry for a multi-entry field from one specific entity? (that's specific fields and specific entities, not field types or instances and entity types)  Here's some possibilities I've looked into which don't work:   Loading the entity with entity_load(), setting the field entry to =null or =array(), then saving with field_attach_update(). It's the closest I've found but it leaves a zombie null field entry in the database which shows up as a blank row on forms until the form is saved and hook_field_is_empty() can kick in (hook_field_is_empty() is configured such that =null or =array() will flag as empty). Loading the entity with entity_load(), unsetting the field entry by key, then saving with field_attach_update(). This seems to do nothing - it seems that Drupal interprets the entry not being there as a sign to not modify it. (strangely I also sometimes get maximum query time expiration timeouts when trying this approach) field_attach_delete() - this is much too blunt: it kills all fields for the entity field_purge_data() - better, but still too blunt: it kills all entries of the field, not specific entries   So to clarify, I've got code that finds (and loads) an entity which has a field that has multiple entries, and finds a specific entry on that field that needs to be removed. I want to remove that entry completely, without touching any other entries or any other fields on the entity. Is it possible for a system to have negative potential energy? With respect to both gravity and electromagnetism, to the best of my understanding potential energy is added or subtracted from a system based on the distance between two objects such as charged or massive objects.  Would this then imply that when oppositely charged objects or two massive objects are brought together within a small enough radius that the drop in potential energy would be greater than the combined mass of the two objects making the net mass/energy of the system negative? Conditional sentences not starting with "if" Were I rich, I would live on Long Island.   If I were rich, I would live on Long Island.   Is the first sentence still used, or is used in particular contexts (in example, to give emphasis to the sentence)? Summability vs Unconditional Convergence I'm reading that summability and unconditional convergence are the same. (At least if the index set is countable, so unconditional convergence makes sense.)  Then unconditional convergence is nothing else than convergence of the net of all rearranged partial sums. Thus uniqueness of the limit becomes fairly easy as the limit of every net in a Hausdorff space is unique.  But the usual proof deals with separating functionals on Banach spaces, which is a much more serious technique. So I think there must be a hook in my reasoning. Can somebody resolve this issue? Thanks a lot!  Best Regards, Freeze_S Relative performance of std::vector vs. std::list vs. std::slist? I can't seem to find a few of the Stones, so, is there a list available with the location of all the stones? How to submit a form when the return key is pressed? Can someone please tell me how to submit an HTML form when the return key is pressed and if there are no buttons in the form? The submit button is not there. I am using a custom div instead of that. Number of ancestors 750 years ago I have 2 ancestors, a father and a mother. Two generations back - 4 ancestors. Three generations back - 8 ancestors.  30 generations back: 2^n = 2^30 = ~1,000,000,000 ancestors.  If a generation is 25 years long, 30 generations are 750 years and 30 generations ago the year was 1,267. But the world population was only 400,000,000 people so how can my math be wrong? and is there a way to estimate the number of ancestors I had 750 years ago? Order a MySQL table by two columns How do I sort a MySQL table by two columns? What I want are articles sorted by highest ratings first, then most recent date.  As an example, this would be a sample output (left # is the rating, then the article title, then the article date)  +================+=============================+==============+ | article_rating | article                     | article_time | +================+=============================+==============+ | 50             | This article rocks          | Feb 4, 2009  | +----------------+-----------------------------+--------------+ | 35             | This article is pretty good | Feb 1, 2009  | +----------------+-----------------------------+--------------+ | 5              | This Article isn't so hot   | Jan 25, 2009 | +================+=============================+==============+  The relevant SQL I'm using is: ORDER BY article_rating, article_time DESC  I can sort by one or the other, but not both.