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Programming-Idioms

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  • Fortran

Idiom #14 Pick uniformly a random floating point number in [a..b)

Pick a random number greater than or equals to a, strictly inferior to b. Precondition : a < b.

call random_number(c)
d = a + (b-a) * c

c is a temporary variable in [0:1[.
#include <stdlib.h>
double pick(double a, double b)
{
	return a + (double)rand() / ((double)RAND_MAX * (b - a));
}

this is not uniformly distributed!!

New implementation...
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