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Speed up the loop operation in R
...r speed gains through more efficient means of calling R:
Compile your R script. Or use the Ra and jit packages in concert for just-in-time compilation (Dirk has an example in this presentation).
Make sure you're using an optimized BLAS. These provide across-the-board speed gains. Honestly, it's...
Why are elementwise additions much faster in separate loops than in a combined loop?
...llocations will appear at the same offset from a page-boundary.
Here's the test code:
int main(){
const int n = 100000;
#ifdef ALLOCATE_SEPERATE
double *a1 = (double*)malloc(n * sizeof(double));
double *b1 = (double*)malloc(n * sizeof(double));
double *c1 = (double*)malloc(n * sizeo...
Remove characters from C# string
...lation, where dozens of lines of code and multiple loops would be needed. Testing the compiled version of this regex against a simple unoptimised loop 50000 times, the regex is 6X slower.
– Tony Cheetham
Feb 13 '18 at 12:07
...
How to check if the string is empty?
... then you should use myString == "". See the documentation on Truth Value Testing for other values that are false in Boolean contexts.
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Advantages of using prototype, vs defining methods straight in the constructor? [duplicate]
...// Create 2 instances:
var ins1 = new Class(),
ins2 = new Class();
// Test the calc method:
console.log(ins1.calc(1,1), ins2.calc(1,1));
// -> 2, 2
// Change the prototype method
Class.prototype.calc = function () {
var args = Array.prototype.slice.apply(arguments),
res = 0, c;
...
MySQL: selecting rows where a column is null
...
To search for column values that are NULL, you cannot use an expr = NULL test. The following statement returns no rows, because expr = NULL is never true for any expression
Solution
SELECT pid FROM planets WHERE userid IS NULL;
To test for NULL, use the IS NULL and IS NOT NULL operators.
opera...
Execute another jar in a Java program
...entry while creating a JAR.
>p.mf (content of p.mf)
Main-Class: pk.Test
>Test.java
package pk;
public class Test{
public static void main(String []args){
System.out.println("Hello from Test");
}
}
Use Process class and it's methods,
public class Exec
{
public static void ...
How to get the text node of an element?
...
Not sure why but I'm unssuccsessful when testing the theory above. I ran the following jQuery("*").each(function() { console.log(this.nodeType); }) and I got 1 for all the node types.
– Batandwa
Jan 6 '14 at 6:51
...
Why do results vary based on curly brace placement?
... terminated, so your first example looks effectively like this:
function test()
{
return; // <- notice the inserted semicolon
{
javascript: "fantastic"
};
}
See also Douglas Crockford's JS style guide, which mentions semicolon insertion.
In your second example you return an object...
Remove all whitespaces from NSString
...
I prefer using regex like this:
NSString *myString = @"this is a test";
NSString *myNewString = [myString stringByReplacingOccurrencesOfString:@"\\s"
withString:@""
options:NSRegularExpressionSearch
...