fg_math.h File Reference

Routines for statistics and advanced traffic generation. More...

#include "config.h"
#include "daemon.h"

Go to the source code of this file.

Functions
int	dist_bernoulli (struct flow *flow, const double p)
double	dist_chisq (struct flow *flow, const double nu)
double	dist_exponential (struct flow *flow, const double mu)
double	dist_lognormal (struct flow *flow, const double zeta, const double sigma)
double	dist_normal (struct flow *flow, const double mu, const double sigma_square)
double	dist_pareto (struct flow *flow, const double k, const double x_min)
double	dist_uniform (struct flow *flow, const double minval, const double maxval)
double	dist_weibull (struct flow *flow, const double alpha, const double beta)
void	free_math_functions (struct flow *flow)
void	init_math_functions (struct flow *flow, unsigned long seed)

Detailed Description

Routines for statistics and advanced traffic generation.

Definition in file fg_math.h.

Function Documentation

dist_bernoulli()

int dist_bernoulli	(	struct flow *	flow,
		const double	p
	)

Definition at line 179 of file fg_math.c.

{
#ifdef HAVE_LIBGSL
        gsl_rng * r = flow->r;
        return gsl_ran_bernoulli (r, p);
#else /* HAVE_LIBGSL */
        UNUSED_ARGUMENT(flow);
        return rn_uniform_zero_to_one() <= p;
#endif /* HAVE_LIBGSL */
}

dist_chisq()

double dist_chisq	(	struct flow *	flow,
		const double	nu
	)

Definition at line 219 of file fg_math.c.

{
#ifdef HAVE_LIBGSL
        gsl_rng * r = flow->r;
        return gsl_ran_chisq(r, nu);
#else /* HAVE_LIBGSL */
        /* not implemented */
        UNUSED_ARGUMENT(flow);
        UNUSED_ARGUMENT(nu);
        return 0;
#endif /* HAVE_LIBGSL */
}

dist_exponential()

double dist_exponential	(	struct flow *	flow,
		const double	mu
	)

Definition at line 123 of file fg_math.c.

{
#ifdef HAVE_LIBGSL
        gsl_rng * r = flow->r;
        return gsl_ran_exponential(r, mu);
#else /* HAVE_LIBGSL */
        UNUSED_ARGUMENT(flow);
        return -log(rn_uniform())+mu;
#endif /* HAVE_LIBGSL */
}

dist_lognormal()

double dist_lognormal	(	struct flow *	flow,
		const double	zeta,
		const double	sigma
	)

Definition at line 163 of file fg_math.c.

{
#ifdef HAVE_LIBGSL
        gsl_rng * r = flow->r;
        return gsl_ran_lognormal (r, zeta, sigma);
#else /* HAVE_LIBGSL */
        /* not implemented */
        UNUSED_ARGUMENT(flow);
        UNUSED_ARGUMENT(zeta);
        UNUSED_ARGUMENT(sigma);
        return 0;
#endif /* HAVE_LIBGSL */
}

dist_normal()

double dist_normal	(	struct flow *	flow,
		const double	mu,
		const double	sigma_square
	)

Definition at line 149 of file fg_math.c.

{
#ifdef HAVE_LIBGSL
        const gsl_rng * r = flow->r;
        return gsl_ran_gaussian (r, sigma_square) + mu;
#else /* HAVE_LIBGSL */
        UNUSED_ARGUMENT(flow);
        const double x = rn_uniform_minusone_to_one();
        return (1.0 / sqrt(2.0*M_PI*sigma_square)) *
                exp((-pow ((x-mu),2)) / (2 * sigma_square));
#endif /* HAVE_LIBGSL */
}

dist_pareto()

double dist_pareto	(	struct flow *	flow,
		const double	k,
		const double	x_min
	)

Definition at line 190 of file fg_math.c.

{
#ifdef HAVE_LIBGSL
        gsl_rng * r = flow->r;
        return gsl_ran_pareto (r, k, x_min);
#else /* HAVE_LIBGSL */
        UNUSED_ARGUMENT(flow);
        const double x = rn_uniform();
        if (x < x_min)
                return 0;
        else
                return  (k/x_min) * pow (x_min/x,k+1);
#endif /* HAVE_LIBGSL */
}

dist_uniform()

double dist_uniform	(	struct flow *	flow,
		const double	minval,
		const double	maxval
	)

Definition at line 136 of file fg_math.c.

{
#ifdef HAVE_LIBGSL
        gsl_rng * r = flow->r;
        return gsl_ran_flat(r, minval, maxval);
#else /* HAVE_LIBGSL */
        UNUSED_ARGUMENT(flow);
        const double x = rn_uniform_zero_to_one();
        return ((maxval-minval) * x) + minval;
#endif /* HAVE_LIBGSL */
}

dist_weibull()

double dist_weibull	(	struct flow *	flow,
		const double	alpha,
		const double	beta
	)

Definition at line 206 of file fg_math.c.

{
#ifdef HAVE_LIBGSL
        gsl_rng * r = flow->r;
        return gsl_ran_weibull (r, alpha, beta);
#else /* HAVE_LIBGSL */
        UNUSED_ARGUMENT(flow);
        const double x = rn_uniform_zero_to_one();
        return  alpha * beta * pow (x,beta-1.0) * exp(-alpha * pow(x,beta));
#endif /* HAVE_LIBGSL */
}

free_math_functions()

void free_math_functions

(

struct flow *

flow

)

Definition at line 97 of file fg_math.c.

{
#ifdef HAVE_LIBGSL
        gsl_rng_free(flow->r);
#else /* HAVE_LIBGSL */
        UNUSED_ARGUMENT(flow);
#endif /* HAVE_LIBGSL */
}

init_math_functions()

void init_math_functions	(	struct flow *	flow,
		unsigned long	seed
	)

Definition at line 58 of file fg_math.c.

{
        int rc;
#ifndef HAVE_LIBGSL
        UNUSED_ARGUMENT(flow);
#endif /* HAVE_LIBGSL */
        /* set rounding */
        fesetround(FE_TONEAREST);
 
        /* initalize rng */
#ifdef HAVE_LIBGSL
        const gsl_rng_type * T;
        gsl_rng_env_setup();
        T = gsl_rng_default;
        flow->r = gsl_rng_alloc (T);
#endif /* HAVE_LIBGSL */
 
        if (!seed) {
        /* if no seed supplied use urandom */
                DEBUG_MSG(LOG_WARNING, "client did not supply random seed value");
                int data = open("/dev/urandom", O_RDONLY);
                rc = read(data, &seed, sizeof (long) );
                close(data);
                if(rc == -1)
                        crit("read /dev/urandom failed");
        }
 
#ifdef HAVE_LIBGSL
        gsl_rng_set (flow->r, seed);
        DEBUG_MSG(LOG_WARNING, "initalized local libgsl random functions for "
                  "flow %d with seed %lu, gsl generator is: %s",
                  flow->id,seed,gsl_rng_name (flow->r));
#else /* HAVE_LIBGSL */
        srand((unsigned)seed);
        DEBUG_MSG(LOG_WARNING, "initalized posix random functions with seed "
                  "%u", (unsigned)seed);
#endif /* HAVE_LIBGSL */
}