#include "blaswrap.h" /* -- translated by f2c (version 19990503). You must link the resulting object file with the libraries: -lf2c -lm (in that order) */ #include "f2c.h" doublereal slarnd_(integer *idist, integer *iseed) { /* System generated locals */ real ret_val; /* Builtin functions */ double log(doublereal), sqrt(doublereal), cos(doublereal); /* Local variables */ static real t1, t2; extern doublereal slaran_(integer *); /* -- LAPACK auxiliary routine (version 3.0) -- Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., Courant Institute, Argonne National Lab, and Rice University September 30, 1994 Purpose ======= SLARND returns a random real number from a uniform or normal distribution. Arguments ========= IDIST (input) INTEGER Specifies the distribution of the random numbers: = 1: uniform (0,1) = 2: uniform (-1,1) = 3: normal (0,1) ISEED (input/output) INTEGER array, dimension (4) On entry, the seed of the random number generator; the array elements must be between 0 and 4095, and ISEED(4) must be odd. On exit, the seed is updated. Further Details =============== This routine calls the auxiliary routine SLARAN to generate a random real number from a uniform (0,1) distribution. The Box-Muller method is used to transform numbers from a uniform to a normal distribution. ===================================================================== Generate a real random number from a uniform (0,1) distribution Parameter adjustments */ --iseed; /* Function Body */ t1 = slaran_(&iseed[1]); if (*idist == 1) { /* uniform (0,1) */ ret_val = t1; } else if (*idist == 2) { /* uniform (-1,1) */ ret_val = t1 * 2.f - 1.f; } else if (*idist == 3) { /* normal (0,1) */ t2 = slaran_(&iseed[1]); ret_val = sqrt(log(t1) * -2.f) * cos(t2 * 6.2831853071795864769252867663f); } return ret_val; /* End of SLARND */ } /* slarnd_ */