/* -- translated by f2c (version 19940927).
You must link the resulting object file with the libraries:
-lf2c -lm (in that order)
*/
#include "f2c.h"
/* Complex */ VOID clarnd_(complex * ret_val, integer *idist, integer *iseed)
{
/* System generated locals */
doublereal d__1, d__2;
complex q__1, q__2, q__3;
/* Builtin functions */
double log(doublereal), sqrt(doublereal);
void c_exp(complex *, complex *);
/* Local variables */
static real t1, t2;
extern doublereal slaran_(integer *);
/* -- LAPACK auxiliary routine (version 2.0) --
Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
Courant Institute, Argonne National Lab, and Rice University
September 30, 1994
Purpose
=======
CLARND returns a random complex number from a uniform or normal
distribution.
Arguments
=========
IDIST (input) INTEGER
Specifies the distribution of the random numbers:
= 1: real and imaginary parts each uniform (0,1)
= 2: real and imaginary parts each uniform (-1,1)
= 3: real and imaginary parts each normal (0,1)
= 4: uniformly distributed on the disc abs(z) <= 1
= 5: uniformly distributed on the circle abs(z) = 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 pair of real random numbers from a uniform (0,1)
distribution
Parameter adjustments */
--iseed;
/* Function Body */
t1 = slaran_(&iseed[1]);
t2 = slaran_(&iseed[1]);
if (*idist == 1) {
/* real and imaginary parts each uniform (0,1) */
q__1.r = t1, q__1.i = t2;
ret_val->r = q__1.r, ret_val->i = q__1.i;
} else if (*idist == 2) {
/* real and imaginary parts each uniform (-1,1) */
d__1 = t1 * 2.f - 1.f;
d__2 = t2 * 2.f - 1.f;
q__1.r = d__1, q__1.i = d__2;
ret_val->r = q__1.r, ret_val->i = q__1.i;
} else if (*idist == 3) {
/* real and imaginary parts each normal (0,1) */
d__1 = sqrt(log(t1) * -2.f);
d__2 = t2 * 6.2831853071795864769252867663f;
q__3.r = 0.f, q__3.i = d__2;
c_exp(&q__2, &q__3);
q__1.r = d__1 * q__2.r, q__1.i = d__1 * q__2.i;
ret_val->r = q__1.r, ret_val->i = q__1.i;
} else if (*idist == 4) {
/* uniform distribution on the unit disc abs(z) <= 1 */
d__1 = sqrt(t1);
d__2 = t2 * 6.2831853071795864769252867663f;
q__3.r = 0.f, q__3.i = d__2;
c_exp(&q__2, &q__3);
q__1.r = d__1 * q__2.r, q__1.i = d__1 * q__2.i;
ret_val->r = q__1.r, ret_val->i = q__1.i;
} else if (*idist == 5) {
/* uniform distribution on the unit circle abs(z) = 1 */
d__1 = t2 * 6.2831853071795864769252867663f;
q__2.r = 0.f, q__2.i = d__1;
c_exp(&q__1, &q__2);
ret_val->r = q__1.r, ret_val->i = q__1.i;
}
return ;
/* End of CLARND */
} /* clarnd_ */