core-lightning/common/random_select.c

#include "config.h"
#include <common/pseudorand.h>
#include <common/random_select.h>

bool random_select(double weight, double *tot_weight)
{
	*tot_weight += weight;
	if (weight == 0)
		return false;

	return pseudorand_double() <= weight / *tot_weight;
}
check: make sure all files outside contrib/ include "config.h" first. And turn "" includes into full-path (which makes it easier to put config.h first, and finds some cases check-includes.sh missed previously). config.h sets _GNU_SOURCE which really needs to be done before any '#includes': we mainly got away with it with glibc, but other platforms like Alpine may have stricter requirements. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> 2021-12-04 12:23:56 +01:00			`#include "config.h"`
common/random_select: central place for reservoir sampling. Turns out we can make quite a simple API out of it. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> 2020-08-11 07:05:56 +02:00			`#include <common/pseudorand.h>`
			`#include <common/random_select.h>`

			`bool random_select(double weight, double *tot_weight)`
			`{`
			`*tot_weight += weight;`
			`if (weight == 0)`
			`return false;`

			`return pseudorand_double() <= weight / *tot_weight;`
			`}`