Files
openairinterface5g/openair1/SIMULATION/TOOLS/rangen_double.c
T

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3.4 KiB
C

/*******************************************************************************
OpenAirInterface
Copyright(c) 1999 - 2014 Eurecom
OpenAirInterface is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
OpenAirInterface is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with OpenAirInterface.The full GNU General Public License is
included in this distribution in the file called "COPYING". If not,
see <http://www.gnu.org/licenses/>.
Contact Information
OpenAirInterface Admin: openair_admin@eurecom.fr
OpenAirInterface Tech : openair_tech@eurecom.fr
OpenAirInterface Dev : openair4g-devel@lists.eurecom.fr
Address : Eurecom, Campus SophiaTech, 450 Route des Chappes, CS 50193 - 06904 Biot Sophia Antipolis cedex, FRANCE
*******************************************************************************/
#ifdef USER_MODE
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#endif
#include "defs.h"
static unsigned int seed, iy, ir[98];
/*
@defgroup _uniformdouble
@ingroup numerical Uniform linear congruential random number generator.
*/
/*!\brief Initialization routine for Uniform/Gaussian random number generators. */
#define a 1664525lu
#define mod 4294967296.0 /* is 2**32 */
void randominit(unsigned seed_init)
{
int i;
// this need to be integrated with the existing rng, like taus: navid
msg("Initializing random number generator, seed %x\n",seed_init);
if (seed_init == 0) {
srand((unsigned)time(NULL));
seed = (unsigned int) rand();
} else {
seed = seed_init;
}
if (seed % 2 == 0) seed += 1; /* seed and mod are relative prime */
for (i=1; i<=97; i++) {
seed = a*seed; /* mod 2**32 */
ir[i]= seed; /* initialize the shuffle table */
}
iy=1;
}
/*!\brief Uniform linear congruential random number generator on \f$[0,1)\f$. Returns a double-precision floating-point number.*/
double uniformrandom(void)
{
#define a 1664525lu
#define mod 4294967296.0 /* is 2**32 */
int j;
j=1 + 97.0*iy/mod;
iy=ir[j];
seed = a*seed; /* mod 2**32 */
ir[j] = seed;
return( (double) iy/mod );
}
/*
@defgroup _gaussdouble Gaussian random number generator based on modified Box-Muller transformation.
@ingroup numerical
*/
/*!\brief Gaussian random number generator based on modified Box-Muller transformation.Returns a double-precision floating-point number. */
double gaussdouble(double mean, double variance)
{
static int iset=0;
static double gset;
double fac,r,v1,v2;
if (iset == 0) {
do {
v1 = 2.0*uniformrandom()-1.0;
v2 = 2.0*uniformrandom()-1.0;
r = v1*v1+v2*v2;
} while (r >= 1.0);
fac = sqrt(-2.0*log(r)/r);
gset= v1*fac;
iset=1;
return(sqrt(variance)*v2*fac + mean);
} else {
iset=0;
return(sqrt(variance)*gset + mean);
}
}
#ifdef MAIN
main(int argc,char **argv)
{
int i;
randominit();
for (i=0; i<10; i++) {
printf("%f\n",gaussdouble(0.0,1.0));
}
}
#endif