127 lines
3.4 KiB
C
127 lines
3.4 KiB
C
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/* -- translated by f2c (version 19940927).
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You must link the resulting object file with the libraries:
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-lf2c -lm (in that order)
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*/
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#include "f2c.h"
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/* Double Complex */ VOID zlarnd_(doublecomplex * ret_val, integer *idist,
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integer *iseed)
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{
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/* System generated locals */
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doublereal d__1, d__2;
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doublecomplex z__1, z__2, z__3;
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/* Builtin functions */
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double log(doublereal), sqrt(doublereal);
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void z_exp(doublecomplex *, doublecomplex *);
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/* Local variables */
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static doublereal t1, t2;
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extern doublereal dlaran_(integer *);
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/* -- LAPACK auxiliary routine (version 2.0) --
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Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
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Courant Institute, Argonne National Lab, and Rice University
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September 30, 1994
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Purpose
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=======
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ZLARND returns a random complex number from a uniform or normal
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distribution.
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Arguments
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=========
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IDIST (input) INTEGER
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Specifies the distribution of the random numbers:
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= 1: real and imaginary parts each uniform (0,1)
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= 2: real and imaginary parts each uniform (-1,1)
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= 3: real and imaginary parts each normal (0,1)
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= 4: uniformly distributed on the disc abs(z) <= 1
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= 5: uniformly distributed on the circle abs(z) = 1
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ISEED (input/output) INTEGER array, dimension (4)
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On entry, the seed of the random number generator; the array
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elements must be between 0 and 4095, and ISEED(4) must be
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odd.
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On exit, the seed is updated.
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Further Details
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===============
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This routine calls the auxiliary routine DLARAN to generate a random
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real number from a uniform (0,1) distribution. The Box-Muller method
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is used to transform numbers from a uniform to a normal distribution.
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=====================================================================
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Generate a pair of real random numbers from a uniform (0,1)
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distribution
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Parameter adjustments */
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--iseed;
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/* Function Body */
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t1 = dlaran_(&iseed[1]);
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t2 = dlaran_(&iseed[1]);
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if (*idist == 1) {
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/* real and imaginary parts each uniform (0,1) */
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z__1.r = t1, z__1.i = t2;
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ret_val->r = z__1.r, ret_val->i = z__1.i;
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} else if (*idist == 2) {
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/* real and imaginary parts each uniform (-1,1) */
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d__1 = t1 * 2. - 1.;
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d__2 = t2 * 2. - 1.;
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z__1.r = d__1, z__1.i = d__2;
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ret_val->r = z__1.r, ret_val->i = z__1.i;
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} else if (*idist == 3) {
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/* real and imaginary parts each normal (0,1) */
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d__1 = sqrt(log(t1) * -2.);
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d__2 = t2 * 6.2831853071795864769252867663;
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z__3.r = 0., z__3.i = d__2;
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z_exp(&z__2, &z__3);
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z__1.r = d__1 * z__2.r, z__1.i = d__1 * z__2.i;
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ret_val->r = z__1.r, ret_val->i = z__1.i;
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} else if (*idist == 4) {
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/* uniform distribution on the unit disc abs(z) <= 1 */
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d__1 = sqrt(t1);
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d__2 = t2 * 6.2831853071795864769252867663;
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z__3.r = 0., z__3.i = d__2;
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z_exp(&z__2, &z__3);
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z__1.r = d__1 * z__2.r, z__1.i = d__1 * z__2.i;
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ret_val->r = z__1.r, ret_val->i = z__1.i;
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} else if (*idist == 5) {
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/* uniform distribution on the unit circle abs(z) = 1 */
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d__1 = t2 * 6.2831853071795864769252867663;
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z__2.r = 0., z__2.i = d__1;
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z_exp(&z__1, &z__2);
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ret_val->r = z__1.r, ret_val->i = z__1.i;
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}
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return ;
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/* End of ZLARND */
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} /* zlarnd_ */
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