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What's the difference between libev and libevent?
...ng small watchers for each event type (an I/O watcher uses 56 bytes on x86_64 compared to 136 for libevent), allowing extra event types such as timers based on wallclock vs. monotonic time, inter-thread interruptions, prepare and check watchers to embed other event loops or to be embedded and so on....
Do declared properties require a corresponding instance variable?
...using the Modern Objective-C Runtime (that's either iOS 3.x or greater, or 64-bit Snow Leopard or greater) then you do not need to define ivars for your properties in cases like this.
When you @synthesize the property, the ivar will in effect be synthesized also for you. This gets around the "fragi...
How to sort a dataframe by multiple column(s)
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Ari B. FriedmanAri B. Friedman
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How to compute the similarity between two text documents?
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<5x5 sparse matrix of type '<class 'numpy.float64'>'
with 17 stored elements in Compressed Sparse Row format>
You can convert the sparse array to a NumPy array via .toarray() or .A:
>>> pairwise_similarity.toarray() ...
Correct way to use StringBuilder in SQL
...have been 26 to start with, then doubled to 52, then 104, 208, 416, 832, 1664, 3328, and finally 6656). Only significant if this is a hotspot, but still, if you know in advance... :-)
– T.J. Crowder
Jan 4 '12 at 12:24
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NumPy: function for simultaneous max() and min()
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as of numpy 1.8 min and max are vectorized on amd64 platforms,on my core2duo numpy performs as well as this fortran code. But a single pass would be advantageous if the array exceed the size of the larger cpu caches.
– jtaylor
Mar 7 '1...
Do HTML WebSockets maintain an open connection for each client? Does this scale?
...ction consists of destination ip & destination port. That means that ±64k ports limit is actually ONLY for a single client. Theoretically, the server can have any number of open connections, limited ONLY by its hardware.
– Rizon
Dec 21 '13 at 1:35
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With arrays, why is it the case that a[5] == 5[a]?
...t back in the 70's when C was designed, computers didn't have much memory (64KB was a lot), so the C compiler didn't do much syntax checking. Hence "X[Y]" was rather blindly translated into "*(X+Y)"
This also explains the "+=" and "++" syntaxes. Everything in the form "A = B + C" had the same c...
Rails: FATAL - Peer authentication failed for user (PG::Error)
...versions are available
psql=# select VERSION();
PostgreSQL 9.1.13 on x86_64-unk.... # so version is 9.1
Now Open postgres user
vim /etc/postgresql/9.1/main/pg_hba.conf
9.1 is version return form upper command
and replace
local all postgres ...
LINQ to Entities only supports casting EDM primitive or enumeration types with IEntity interface
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Some additional explanations regarding the class "fix".
This answer shows two different expres...