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What makes JNI calls slow?
...thods, in 2010 I measured calls at an average 40 ns on my Windows desktop, and 11 ns on my Mac desktop. Unless you're making many calls, you're not going to notice.
That said, calling a native method can be slower than making a normal Java method call. Causes include:
Native methods will not be i...
Forward declaring an enum in C++
... char or an int, or something else.
From Section 7.2.5 of the ISO C++ Standard:
The underlying type of an enumeration is an integral type that can represent all the enumerator values defined in the enumeration. It is implementation-defined which integral type is used as the underlying type fo...
How to fix Git error: object file is empty?
...Continue deleting the empty files. You can also cd into the .git directory and run find . -type f -empty -delete -print to remove all empty files. Eventually git started telling me it was actually doing something with the object directories:
nathanvan@nathanvan-N61Jq:~/workspace/mcmc-chapter$ git ...
When should I use GET or POST method? What's the difference between them?
...nfuses the concepts a bit. A POST request gets input from the query string and through the request body. A GET request just gets input from the query string. So a POST request is a superset of a GET request; you can use $_GET in a POST request, and it may even make sense to have parameters with the ...
node and Error: EMFILE, too many open files
...
For when graceful-fs doesn't work... or you just want to understand where the leak is coming from. Follow this process.
(e.g. graceful-fs isn't gonna fix your wagon if your issue is with sockets.)
From My Blog Article: http://www.blakerobertson.com/devlog/2014/1/11/how-to-determine-whats...
Colorized grep — viewing the entire file with highlighted matches
...y, "pattern|$" will match lines that have the pattern you're searching for AND lines that have an end -- that is, all of them. Because the end of a line isn't actually any characters, the colorized portion of the output will just be your pattern. Thanks Ryan!
– zslayton
...
How to add an extra column to a NumPy array
...
I think a more straightforward solution and faster to boot is to do the following:
import numpy as np
N = 10
a = np.random.rand(N,N)
b = np.zeros((N,N+1))
b[:,:-1] = a
And timings:
In [23]: N = 10
In [24]: a = np.random.rand(N,N)
In [25]: %timeit b = np.hstac...
How to write inline if statement for print?
...n Python 2.5)
expression_if_true if condition else expression_if_false
And note, that both print a and b = a are statements. Only the a part is an expression. So if you write
print a if b else 0
it means
print (a if b else 0)
and similarly when you write
x = a if b else 0
it means
x = ...
How to convert a std::string to const char* or char*?
...ice that the above is not exception safe. If anything between the new call and the delete call throws, you will leak memory, as nothing will call delete for you automatically. There are two immediate ways to solve this.
boost::scoped_array
boost::scoped_array will delete the memory for you upon go...
Sort array of objects by string property value
...are function body: return a.value - b.value; (ASC)
– Andre Figueiredo
Jan 8 '14 at 12:06
23
@Cerb...