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How to allocate aligned memory only using the standard library?
I just finished a test as part of a job interview, and one question stumped me, even using Google for reference. I'd like to see what the StackOverflow crew can do with it:
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Running PostgreSQL in memory only
...y for this particular question: It's a bad idea to mix with valuable data (and thanks for the warning). For unit-testing with a dedicated DB cluster, a ramdisk is fine.
– Erwin Brandstetter
Jul 12 '15 at 0:32
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What is a sealed trait?
...only extended in a single file, the compiler knows every possible subtypes and can reason about it.
For instance with the declaration:
sealed trait Answer
case object Yes extends Answer
case object No extends Answer
The compiler will emit a warning if a match is not exhaustive:
scala> val x:...
How do I compute derivative using Numpy?
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Automatic Derivatives
Symbolic Differentiation
Compute derivatives by hand.
Finite differences require no external tools but are prone to numerical error and, if you're in a multivariate situation, can take a while.
Symbolic differentiation is ideal if your problem is simple enough. Symbolic...
Configure apache to listen on port other than 80
...ed LISTEN 8079 directive in httpd.conf .
I opened port 8079 in iptables and restarted iptables. I even stopped iptables service.
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How to redirect stderr and stdout to different files in the same line in script?
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Just add them in one line command 2>> error 1>> output
However, note that >> is for appending if the file already has data. Whereas, > will overwrite any existing data in the file.
So, command 2> error 1> output if you do not...
Python 3 turn range to a list
...gh since you can come by the value of my_list[i] more efficiently (i + 1), and if you just need to iterate over it, you can just fall back on range.
Also note that on python2.x, xrange is still indexable1. This means that range on python3.x also has the same property2
1print xrange(30)[12] works ...
How to set auto increment primary key in PostgreSQL?
I have a table in PostgreSQL with 22 columns, and I want to add an auto increment primary key.
7 Answers
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How can I get a count of the total number of digits in a number?
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I'm afraid ceil(log10(10)) = ceil(1) = 1, and not 2 as it should be for this question!
– ysap
Dec 19 '10 at 18:08
3
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RESTful Authentication
What does RESTful Authentication mean and how does it work? I can't find a good overview on Google. My only understanding is that you pass the session key (remeberal) in the URL, but this could be horribly wrong.
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