How does a FIFO (named pipe) differs from a regular pipe (unnamed pipe)?
What is the purpose of using a FIFO vs a temporary file or a pipe?
Combining two covariance matrices I'm calculating the covariance of a distribution in parallel and I need to combine the distributed results into on singular Gaussian. How do I combine the two?  Linearly interpolating between the two almost works, if they are similarly distributed and sized.   provides a forumla at the bottom for combination but it doesn't seem right; two identically distributed distributions should have the same covariance, but the formula at the bottom of the page doubles the covariance.  Is there a way to combine two matrices? Should I format /sdcard and /data if I want to wipe all personal data with Cyanogenmod? I'm trying to completely wipe all personal data from my Nexus 4 with CM installed. I've seen different advice on different sites for making sure all my data is gone:   Just do 'Factory Reset'. Do 'Factory Reset' at least 3 times. Do 'Factory Reset' and wipe dalvik cache. ...   and so on... I'm interested in erasing all traces of my personal data from the device. It's a Nexus 4, so there is no removable storage to worry about.  My guess would be to 'wipe data/factory reset' and 'wipe cache partition' in the main recovery menu. In the mount/storage menu, I would choose 'format /cache', 'format /data', and 'format /data and /data/media (/sdcard)'. Finally, in the advanced menu, I would choose 'wipe dalvik cache'.   Is this thorough enough? Should I also choose 'format /system', 'format /firmware', etc? Are there any options I should steer clear from? I would like the phone to boot to a fresh Cyanogenmod after clearing all data. What compiler warning level do you recommend for different C/C++ compilers?  gcc and g++ will let you get away with a lot on the default level.  I find the best warning level for me is '-Wall'.  And I always try to remove fix the code for the warnings it generates.  (Even the silly ones about using parenthesis for logical precedence rules or to say I really mean 'if (x = y)')  What are your favorite levels for the different compilers, such as Sun CC, aCC (HPUX ?), Visual Studio, intel?  Edit:  I just wanted to point out that I don't use "-Werror" (but I do understand it's utility) on gcc/g++ because, I use:   #warning "this is a note to myself"   in a few places in my code.  Do all the compilers understand the #warning macro? Do the automatic success and failure rules apply to skill checks? We had a rule check tonight that we couldn't answer. On the Pathfinder wiki I could only find info on natural 20s and 1s in regards to attack rolls and saves in combat.  Do they also apply to skill checks? Journal vs conference publications when looking for a job in in computer science I'm currently a post doc in theoretical computer science and I have a double digit number of conference publications, about half of which are at so called "tier 1" conferences (SODA,STOC,...). Unfortunately I only have 1 journal publication so far, mainly due to coauthors dragging their feet.   Will the lack of journal publications have a great impact when applying for a faculty job in cs-theory at some point, and is it advisable to try to up this number before applying? Or is this fully compensated by having sufficiently many conference papers? What is the difference between "gerund" and "infinitive"? What is the difference between "gerund" and "infinitive"? I do not understand the differences.Can you explain them? Let $P(x)$ be a degree $n$ polynomial with distinct roots $r_1, r_2, \cdots r_n$. Prove that   $$\displaystyle\sum_{i=1}^{n}\frac{P''(r_i)}{P'(r_i)}=0$$  My proof: We can equivalently rewrite the polynomial as $(x-r_1)(x-r_2)\cdots(x-r_n)$ and if we plug in the roots in the polynomial, we get that all of them are equal to $0$ so their first derivatives are equal to $1$ and then their second derivatives are equal to $0$ which means that all quotients are equal to $0$ and there for the sum is as well, $Q.E.D$  Don't show the solution please, but if you have a hint, feel free. Thank you. https:// search results appearing on Google for purely http:// site Is there a "smallest" divergent sum? Excel "if-then" formula IF(B4-40&lt;0,0,(B4-40))   Above is my formula to show only positive numbers above 40 in the given cell. If my hours are, let's say, 35, I do not want a value of -5; I want the cell value to be 0. Why is this not working? How to import an FBX file into Blender I am trying to import an FBX file from Unity into Blender. Does anybody know how to do that? If $p$ and $q$ are distinct primes , prove that $$p^{q-1}+q^{p-1} \equiv 1 \pmod {pq}$$     Using Fermat's Theorem we can get $$p^{q-1} \equiv 1 \pmod q, \qquad q^{p-1} \equiv 1 \pmod p.$$  After that I have no idea at all. Can anyone help me please The statement is:     In a commutative ring with 1, every proper ideal is contained in a maximal ideal.   and we prove it using Zorn's lemma, that is, $I$ is an ideal, $P=\{I\subset  A\mid A\text{ is an ideal}\} $, then by set inclusion, every totally ordered subset has a bound, then $P$ has a maximal element $M$.  My question is why $M$ must contain $I$? Some movies feature child characters put in violent situations. This can range from crude language to extreme horror (e.g. torture, gore, etc.). As an example,  and its sequel has plenty of those scenes. It looks like a paradox that children can be actors in movies that are definitely not for children.  Do the directors usually try and avoid exposing the very young actors to the violence of such scenes, e.g. by clever dubbing and editing? Are there laws that require them to do so, just like there are ratings that prevent children from seeing some movies? Let $n$ be an integer such that if $d | n$ then $d + 1 | n + 1.$ Show that $n$ is a prime number Let $n$ be an integer such that for any integer $d$, if $d | n$ then $d + 1 | n + 1$.   Show that $n$ is a prime number or equal to $1$  My workout...  Suppose $n = xy$ for some postive integers $x$ and $y. x|n$, and hence we assume without loss of generality $x + 1|n + 1.$   Then $x|xy + 1$. However, $xy + x$ is divisible by $x$.  This implies $x − 1$ is divisible by $x$, which is an impossibility if $x$ is not equal to $1$.  Therefore whenever $n$ is decomposed into two factors, one must turn out to be $1$. Hence $n$ must be a prime.  I am looking for any other method which solves this quickly and more quickly... What "exactly" happens when someone turns to the Dark Side? When I saw the original Star Wars saga as a kid, the concept of the Dark Side imprinted in me was quite simple. You did a bad thing, so you're a bad person so you go to the Dark Side and keep doing bad things.  Now, obviously this doesn't hold true in reality. In my mind it is perfectly reasonable for Luke to kill the Emperor and Vader and then just flee the Death Star and rejoin the Alliance. After all they are at war, those are enemy officers that have captured him and are taunting him by threatening with death of all loved ones and the whole operation was intended to kill the Emperor anyway.   The same would hold true for Anakin. He could have killed Mace Windu to save the Chancellor and Padme but that doesn't mean he's going to then go mad and kill all Jedis including children. It doesn't add up from a merely psychological point of view. He had a set of objectives and that made him want to keep the Chancellor alive (quite valid by the way, Mace Windu is quite clumsy on that) but just after killing him he goes into "Yes master I'll do whatever you say" which from a normal point of view will NEVER ever make sense.  In both cases it seems like the assumption is once you use the Dark Side you completely turn to the Dark Side and become a different person that you were before. That would be coherent with Anakin "dying" and Vader being born.  Is that the way the Dark Side works? Is there any canon information about what happens when someone turns to the Dark Side? Specifically to whether they become a different person or how he or she actually changes?  Note: Vader is angry after he finds out Padme is dead, even though he's already turned.  Example of what I mean. In Buffy they explain how people that turn into Vampires lose their soul and it's taken over by a demon, and thus they are, in all effects, a different person with their memories. Can md5 be used for encrypting data? I know that md5 shouldn't be used for password hashing because of collisions and possibility of making dictionary attacks e.g. using rainbow tables. But what about other uses? Can I use md5 for encrypting data?  Say, attacker gains access to database where sensitive data was stored using md5. He wants to know just this data that was hashed, not another data that gives this hash. Can he do it?  I know that there are better cryptographic hash functions so don't suggest to use them if md5 is enough. Solving a Diophantine equation with a large solution Textbook clarification: $\log = \ln$ Textbook reads:     All logarithms are natural logarithms: $\log = \ln$.   Does this mean $n\log(n) = n\ln(n)$? I created one event receiver and deployed it, but only users who are site collection admins are able to view this web part. I have included the SPSecurity.RunWithElevatedPrivileges but the same thing. What am I missing?  Below is my code   public override void ItemAdding(SPItemEventProperties properties)     base.ItemAdding(properties);     SPSecurity.RunWithElevatedPrivileges(delegate()        {SPWeb web = properties.OpenWeb();         base.ItemAdding(properties);         string name= web.Lists[properties.ListId].Fields["first name"].InternalName;          var list = web.Lists["location names"];    });}