RND.c File Reference

Random Number Distributions, interface. More...

#include <RND.h>
#include <math.h>

Functions
static unsigned int	RND__lc0_args (unsigned int prv, unsigned int a, unsigned int c)
	Produces a random number in the range 0 - 2**32-1 using a linear congruent method.
void	RND_lc0_init (RND_lc0 *ctx, unsigned int seed)
	Init.
unsigned int	RND_lc0_gen (RND_lc0 *ctx)
	Produces a random number in the range 0 - 2**32-1 using a linear congruent method.
int	RND_normal_lc0_gen (RND_normal_lc0 *ctx)
	Produces a normal distribution.

---

Detailed Description

Random Number Distributions, interface.

Author:

JJRussell - russell@slac.stanford.edu

---

Function Documentation

unsigned int RND__lc0_args	(	unsigned int	prv,
		unsigned int	a,
		unsigned int	c
	)			[inline, static]

Produces a random number in the range 0 - 2**32-1 using a linear congruent method.

Returns:

A random number in the range 0 - 2**32 - 1

Parameters:

	prv	The previous random number
	a	The multiplier
	c	The additive factor

One should scale this number by a suitable factor to produce the desired distribution. No should not use a modulus function. For example, do not do

      r = RND__lc0_args (...) % 256;

To produce a number from 0 - 255. Rather do

     r = RND__lco_args (...) >> 24;

Referenced by RND_lc0_gen(), and RND_normal_lc0_gen().

unsigned int RND_lc0_gen

(

RND_lc0 *

ctx

)

Produces a random number in the range 0 - 2**32-1 using a linear congruent method.

Returns:

A random number in the range 0 - 2**32 - 1

Parameters:

ctx

Context parameter

One should scale this number by a suitable factor to produce the desired distribution. No should not use a modulus function. For example, do not do

      r = RND__lc0_args (...) % 256;

To produce a number from 0 - 255. Rather do

     r = RND__lco_args (...) >> 24;

References _RND_lc0::a, _RND_lc0::c, RND__lc0_args(), and _RND_lc0::seed.

void RND_lc0_init	(	RND_lc0 *	ctx,
		unsigned int	seed
	)

Init.

Returns:

Init random number struct to suggested values

Parameters:

	ctx	Context parameter
	seed	random number seed

References _RND_lc0::a, _RND_lc0::c, and _RND_lc0::seed.

Referenced by SSRSIM_init().

unsigned int RND_normal_lc0_gen

(

RND_normal_lc0 *

ctx

)

Produces a normal distribution.

Returns:

A random number drawn from a normal distribution

Parameters:

ctx

Context parameter

References _RND_lc0::a, _RND_lc0::c, _RND_normal_lc0::lc0, _RND_normal_lc0::mean, RND__lc0_args(), _RND_lc0::seed, and _RND_normal_lc0::sigma.