#include "f2c.h"
#include "blaswrap.h"

/* Double Complex */ VOID zlarnd_(doublecomplex * ret_val, integer *idist, 
	integer *iseed)
{
    /* System generated locals */
    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 */
    doublereal t1, t2;
    extern doublereal dlaran_(integer *);


/*  -- LAPACK auxiliary routine (version 3.1) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/*     November 2006 */

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  ZLARND 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 DLARAN 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. */

/*  ===================================================================== */

/*     .. Parameters .. */
/*     .. */
/*     .. Local Scalars .. */
/*     .. */
/*     .. External Functions .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. Executable Statements .. */

/*     Generate a pair of real random numbers from a uniform (0,1) */
/*     distribution */

    /* Parameter adjustments */
    --iseed;

    /* Function Body */
    t1 = dlaran_(&iseed[1]);
    t2 = dlaran_(&iseed[1]);

    if (*idist == 1) {

/*        real and imaginary parts each uniform (0,1) */

	z__1.r = t1, z__1.i = t2;
	 ret_val->r = z__1.r,  ret_val->i = z__1.i;
    } else if (*idist == 2) {

/*        real and imaginary parts each uniform (-1,1) */

	d__1 = t1 * 2. - 1.;
	d__2 = t2 * 2. - 1.;
	z__1.r = d__1, z__1.i = d__2;
	 ret_val->r = z__1.r,  ret_val->i = z__1.i;
    } else if (*idist == 3) {

/*        real and imaginary parts each normal (0,1) */

	d__1 = sqrt(log(t1) * -2.);
	d__2 = t2 * 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;
	 ret_val->r = z__1.r,  ret_val->i = z__1.i;
    } else if (*idist == 4) {

/*        uniform distribution on the unit disc abs(z) <= 1 */

	d__1 = sqrt(t1);
	d__2 = t2 * 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;
	 ret_val->r = z__1.r,  ret_val->i = z__1.i;
    } else if (*idist == 5) {

/*        uniform distribution on the unit circle abs(z) = 1 */

	d__1 = t2 * 6.2831853071795864769252867663;
	z__2.r = 0., z__2.i = d__1;
	z_exp(&z__1, &z__2);
	 ret_val->r = z__1.r,  ret_val->i = z__1.i;
    }
    return ;

/*     End of ZLARND */

} /* zlarnd_ */