/* -- translated by f2c (version 19940927).
You must link the resulting object file with the libraries:
-lf2c -lm (in that order)
*/
#include "f2c.h"
/* Subroutine */ int slatm1_(integer *mode, real *cond, integer *irsign,
integer *idist, integer *iseed, real *d, integer *n, integer *info)
{
/* System generated locals */
integer i__1, i__2;
doublereal d__1, d__2;
/* Builtin functions */
double pow_dd(doublereal *, doublereal *), pow_ri(real *, integer *), log(
doublereal), exp(doublereal);
/* Local variables */
static real temp;
static integer i;
static real alpha;
extern /* Subroutine */ int xerbla_(char *, integer *);
extern doublereal slaran_(integer *);
extern /* Subroutine */ int slarnv_(integer *, integer *, integer *, real
*);
/* -- LAPACK auxiliary test 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
=======
SLATM1 computes the entries of D(1..N) as specified by
MODE, COND and IRSIGN. IDIST and ISEED determine the generation
of random numbers. SLATM1 is called by SLATMR to generate
random test matrices for LAPACK programs.
Arguments
=========
MODE - INTEGER
On entry describes how D is to be computed:
MODE = 0 means do not change D.
MODE = 1 sets D(1)=1 and D(2:N)=1.0/COND
MODE = 2 sets D(1:N-1)=1 and D(N)=1.0/COND
MODE = 3 sets D(I)=COND**(-(I-1)/(N-1))
MODE = 4 sets D(i)=1 - (i-1)/(N-1)*(1 - 1/COND)
MODE = 5 sets D to random numbers in the range
( 1/COND , 1 ) such that their logarithms
are uniformly distributed.
MODE = 6 set D to random numbers from same distribution
as the rest of the matrix.
MODE < 0 has the same meaning as ABS(MODE), except that
the order of the elements of D is reversed.
Thus if MODE is positive, D has entries ranging from
1 to 1/COND, if negative, from 1/COND to 1,
Not modified.
COND - REAL
On entry, used as described under MODE above.
If used, it must be >= 1. Not modified.
IRSIGN - INTEGER
On entry, if MODE neither -6, 0 nor 6, determines sign of
entries of D
0 => leave entries of D unchanged
1 => multiply each entry of D by 1 or -1 with probability .5
IDIST - CHARACTER*1
On entry, IDIST specifies the type of distribution to be
used to generate a random matrix .
1 => UNIFORM( 0, 1 )
2 => UNIFORM( -1, 1 )
3 => NORMAL( 0, 1 )
Not modified.
ISEED - INTEGER array, dimension ( 4 )
On entry ISEED specifies the seed of the random number
generator. The random number generator uses a
linear congruential sequence limited to small
integers, and so should produce machine independent
random numbers. The values of ISEED are changed on
exit, and can be used in the next call to SLATM1
to continue the same random number sequence.
Changed on exit.
D - REAL array, dimension ( MIN( M , N ) )
Array to be computed according to MODE, COND and IRSIGN.
May be changed on exit if MODE is nonzero.
N - INTEGER
Number of entries of D. Not modified.
INFO - INTEGER
0 => normal termination
-1 => if MODE not in range -6 to 6
-2 => if MODE neither -6, 0 nor 6, and
IRSIGN neither 0 nor 1
-3 => if MODE neither -6, 0 nor 6 and COND less than 1
-4 => if MODE equals 6 or -6 and IDIST not in range 1 to 3
-7 => if N negative
=====================================================================
Decode and Test the input parameters. Initialize flags & seed.
Parameter adjustments */
--d;
--iseed;
/* Function Body */
*info = 0;
/* Quick return if possible */
if (*n == 0) {
return 0;
}
/* Set INFO if an error */
if (*mode < -6 || *mode > 6) {
*info = -1;
} else if (*mode != -6 && *mode != 0 && *mode != 6 && (*irsign != 0 && *
irsign != 1)) {
*info = -2;
} else if (*mode != -6 && *mode != 0 && *mode != 6 && *cond < 1.f) {
*info = -3;
} else if ((*mode == 6 || *mode == -6) && (*idist < 1 || *idist > 3)) {
*info = -4;
} else if (*n < 0) {
*info = -7;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("SLATM1", &i__1);
return 0;
}
/* Compute D according to COND and MODE */
if (*mode != 0) {
switch (abs(*mode)) {
case 1: goto L10;
case 2: goto L30;
case 3: goto L50;
case 4: goto L70;
case 5: goto L90;
case 6: goto L110;
}
/* One large D value: */
L10:
i__1 = *n;
for (i = 1; i <= i__1; ++i) {
d[i] = 1.f / *cond;
/* L20: */
}
d[1] = 1.f;
goto L120;
/* One small D value: */
L30:
i__1 = *n;
for (i = 1; i <= i__1; ++i) {
d[i] = 1.f;
/* L40: */
}
d[*n] = 1.f / *cond;
goto L120;
/* Exponentially distributed D values: */
L50:
d[1] = 1.f;
if (*n > 1) {
d__1 = (doublereal) (*cond);
d__2 = (doublereal) (-1.f / (real) (*n - 1));
alpha = pow_dd(&d__1, &d__2);
i__1 = *n;
for (i = 2; i <= i__1; ++i) {
i__2 = i - 1;
d[i] = pow_ri(&alpha, &i__2);
/* L60: */
}
}
goto L120;
/* Arithmetically distributed D values: */
L70:
d[1] = 1.f;
if (*n > 1) {
temp = 1.f / *cond;
alpha = (1.f - temp) / (real) (*n - 1);
i__1 = *n;
for (i = 2; i <= i__1; ++i) {
d[i] = (real) (*n - i) * alpha + temp;
/* L80: */
}
}
goto L120;
/* Randomly distributed D values on ( 1/COND , 1): */
L90:
alpha = log(1.f / *cond);
i__1 = *n;
for (i = 1; i <= i__1; ++i) {
d[i] = exp(alpha * slaran_(&iseed[1]));
/* L100: */
}
goto L120;
/* Randomly distributed D values from IDIST */
L110:
slarnv_(idist, &iseed[1], n, &d[1]);
L120:
/* If MODE neither -6 nor 0 nor 6, and IRSIGN = 1, assign
random signs to D */
if (*mode != -6 && *mode != 0 && *mode != 6 && *irsign == 1) {
i__1 = *n;
for (i = 1; i <= i__1; ++i) {
temp = slaran_(&iseed[1]);
if (temp > .5f) {
d[i] = -(doublereal)d[i];
}
/* L130: */
}
}
/* Reverse if MODE < 0 */
if (*mode < 0) {
i__1 = *n / 2;
for (i = 1; i <= i__1; ++i) {
temp = d[i];
d[i] = d[*n + 1 - i];
d[*n + 1 - i] = temp;
/* L140: */
}
}
}
return 0;
/* End of SLATM1 */
} /* slatm1_ */