mmc_rand_sfmt.h

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#ifndef _MCEXTREME_SFMT_RAND_H
#define _MCEXTREME_SFMT_RAND_H

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define __device__ static inline

typedef unsigned int RandType;
typedef unsigned int uint;

#define MCX_RNG_NAME       "xorshift128+ RNG"

#define RAND_BUF_LEN       1248    //buffer length
#define RAND_SEED_WORD_LEN      2       //
#define MEXP               19937

__device__ void rng_init(RandType t[RAND_BUF_LEN], RandType tnew[RAND_BUF_LEN], uint* n_seed, int idx);

__device__ void rand_need_more(RandType t[RAND_BUF_LEN], RandType tbuf[RAND_BUF_LEN]);
// generate [0,1] random number for the next scattering length
__device__ float rand_next_scatlen(RandType t[RAND_BUF_LEN]);
// generate [0,1] random number for the next arimuthal angle
__device__ float rand_next_aangle(RandType t[RAND_BUF_LEN]);
// generate random number for the next zenith angle
__device__ float rand_next_zangle(RandType t[RAND_BUF_LEN]);
__device__ float rand_next_reflect(RandType t[RAND_BUF_LEN]);
__device__ float rand_do_roulette(RandType t[RAND_BUF_LEN]);

#ifdef MMC_USE_SSE_MATH
    __device__ void rand_next_aangle_sincos(RandType t[RAND_BUF_LEN], float* si, float* co);
    __device__ float rand_next_scatlen_ps(RandType t[RAND_BUF_LEN]);
#endif

#endif