#include "f2c.h"
/* Subroutine */ int zlarnv_(integer *idist, integer *iseed, integer *n,
doublecomplex *x)
{
/* -- 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
=======
ZLARNV returns a vector of n random complex numbers 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.
N (input) INTEGER
The number of random numbers to be generated.
X (output) COMPLEX*16 array, dimension (N)
The generated random numbers.
Further Details
===============
This routine calls the auxiliary routine DLARUV to generate random
real numbers from a uniform (0,1) distribution, in batches of up to
128 using vectorisable code. The Box-Muller method is used to
transform numbers from a uniform to a normal distribution.
=====================================================================
Parameter adjustments
Function Body */
/* System generated locals */
integer i__1, i__2, i__3, i__4, i__5;
doublereal d__1, d__2;
doublecomplex z__1, z__2, z__3;
/* Builtin functions */
double log(doublereal), sqrt(doublereal);
void z_exp(doublecomplex *, doublecomplex *);
/* Local variables */
static integer i;
static doublereal u[128];
static integer il, iv;
extern /* Subroutine */ int dlaruv_(integer *, integer *, doublereal *);
#define U(I) u[(I)]
#define X(I) x[(I)-1]
#define ISEED(I) iseed[(I)-1]
i__1 = *n;
for (iv = 1; iv <= *n; iv += 64) {
/* Computing MIN */
i__2 = 64, i__3 = *n - iv + 1;
il = min(i__2,i__3);
/* Call DLARUV to generate 2*IL real numbers from a uniform (0,
1)
distribution (2*IL <= LV) */
i__2 = il << 1;
dlaruv_(&ISEED(1), &i__2, u);
if (*idist == 1) {
/* Copy generated numbers */
i__2 = il;
for (i = 1; i <= il; ++i) {
i__3 = iv + i - 1;
i__4 = (i << 1) - 2;
i__5 = (i << 1) - 1;
z__1.r = U((i<<1)-2), z__1.i = U((i<<1)-1);
X(iv+i-1).r = z__1.r, X(iv+i-1).i = z__1.i;
/* L10: */
}
} else if (*idist == 2) {
/* Convert generated numbers to uniform (-1,1) distribut
ion */
i__2 = il;
for (i = 1; i <= il; ++i) {
i__3 = iv + i - 1;
d__1 = U((i << 1) - 2) * 2. - 1.;
d__2 = U((i << 1) - 1) * 2. - 1.;
z__1.r = d__1, z__1.i = d__2;
X(iv+i-1).r = z__1.r, X(iv+i-1).i = z__1.i;
/* L20: */
}
} else if (*idist == 3) {
/* Convert generated numbers to normal (0,1) distributio
n */
i__2 = il;
for (i = 1; i <= il; ++i) {
i__3 = iv + i - 1;
d__1 = sqrt(log(U((i << 1) - 2)) * -2.);
d__2 = U((i << 1) - 1) * 6.2831853071795864769252867663;
z__3.r = 0., z__3.i = d__2;
z_exp(&z__2, &z__3);
z__1.r = d__1 * z__2.r, z__1.i = d__1 * z__2.i;
X(iv+i-1).r = z__1.r, X(iv+i-1).i = z__1.i;
/* L30: */
}
} else if (*idist == 4) {
/* Convert generated numbers to complex numbers uniforml
y
distributed on the unit disk */
i__2 = il;
for (i = 1; i <= il; ++i) {
i__3 = iv + i - 1;
d__1 = sqrt(U((i << 1) - 2));
d__2 = U((i << 1) - 1) * 6.2831853071795864769252867663;
z__3.r = 0., z__3.i = d__2;
z_exp(&z__2, &z__3);
z__1.r = d__1 * z__2.r, z__1.i = d__1 * z__2.i;
X(iv+i-1).r = z__1.r, X(iv+i-1).i = z__1.i;
/* L40: */
}
} else if (*idist == 5) {
/* Convert generated numbers to complex numbers uniforml
y
distributed on the unit circle */
i__2 = il;
for (i = 1; i <= il; ++i) {
i__3 = iv + i - 1;
d__1 = U((i << 1) - 1) * 6.2831853071795864769252867663;
z__2.r = 0., z__2.i = d__1;
z_exp(&z__1, &z__2);
X(iv+i-1).r = z__1.r, X(iv+i-1).i = z__1.i;
/* L50: */
}
}
/* L60: */
}
return 0;
/* End of ZLARNV */
} /* zlarnv_ */