/* -- translated by f2c (version 20100827).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#include "f2c.h"
/* Subroutine */ int igraphdtrsm_(char *side, char *uplo, char *transa, char *diag,
integer *m, integer *n, doublereal *alpha, doublereal *a, integer *
lda, doublereal *b, integer *ldb)
{
/* System generated locals */
integer a_dim1, a_offset, b_dim1, b_offset, i__1, i__2, i__3;
/* Local variables */
integer i__, j, k, info;
doublereal temp;
logical lside;
extern logical igraphlsame_(char *, char *);
integer nrowa;
logical upper;
extern /* Subroutine */ int igraphxerbla_(char *, integer *, ftnlen);
logical nounit;
/* Purpose
=======
DTRSM solves one of the matrix equations
op( A )*X = alpha*B, or X*op( A ) = alpha*B,
where alpha is a scalar, X and B are m by n matrices, A is a unit, or
non-unit, upper or lower triangular matrix and op( A ) is one of
op( A ) = A or op( A ) = A**T.
The matrix X is overwritten on B.
Arguments
==========
SIDE - CHARACTER*1.
On entry, SIDE specifies whether op( A ) appears on the left
or right of X as follows:
SIDE = 'L' or 'l' op( A )*X = alpha*B.
SIDE = 'R' or 'r' X*op( A ) = alpha*B.
Unchanged on exit.
UPLO - CHARACTER*1.
On entry, UPLO specifies whether the matrix A is an upper or
lower triangular matrix as follows:
UPLO = 'U' or 'u' A is an upper triangular matrix.
UPLO = 'L' or 'l' A is a lower triangular matrix.
Unchanged on exit.
TRANSA - CHARACTER*1.
On entry, TRANSA specifies the form of op( A ) to be used in
the matrix multiplication as follows:
TRANSA = 'N' or 'n' op( A ) = A.
TRANSA = 'T' or 't' op( A ) = A**T.
TRANSA = 'C' or 'c' op( A ) = A**T.
Unchanged on exit.
DIAG - CHARACTER*1.
On entry, DIAG specifies whether or not A is unit triangular
as follows:
DIAG = 'U' or 'u' A is assumed to be unit triangular.
DIAG = 'N' or 'n' A is not assumed to be unit
triangular.
Unchanged on exit.
M - INTEGER.
On entry, M specifies the number of rows of B. M must be at
least zero.
Unchanged on exit.
N - INTEGER.
On entry, N specifies the number of columns of B. N must be
at least zero.
Unchanged on exit.
ALPHA - DOUBLE PRECISION.
On entry, ALPHA specifies the scalar alpha. When alpha is
zero then A is not referenced and B need not be set before
entry.
Unchanged on exit.
A - DOUBLE PRECISION array of DIMENSION ( LDA, k ), where k is m
when SIDE = 'L' or 'l' and is n when SIDE = 'R' or 'r'.
Before entry with UPLO = 'U' or 'u', the leading k by k
upper triangular part of the array A must contain the upper
triangular matrix and the strictly lower triangular part of
A is not referenced.
Before entry with UPLO = 'L' or 'l', the leading k by k
lower triangular part of the array A must contain the lower
triangular matrix and the strictly upper triangular part of
A is not referenced.
Note that when DIAG = 'U' or 'u', the diagonal elements of
A are not referenced either, but are assumed to be unity.
Unchanged on exit.
LDA - INTEGER.
On entry, LDA specifies the first dimension of A as declared
in the calling (sub) program. When SIDE = 'L' or 'l' then
LDA must be at least max( 1, m ), when SIDE = 'R' or 'r'
then LDA must be at least max( 1, n ).
Unchanged on exit.
B - DOUBLE PRECISION array of DIMENSION ( LDB, n ).
Before entry, the leading m by n part of the array B must
contain the right-hand side matrix B, and on exit is
overwritten by the solution matrix X.
LDB - INTEGER.
On entry, LDB specifies the first dimension of B as declared
in the calling (sub) program. LDB must be at least
max( 1, m ).
Unchanged on exit.
Further Details
===============
Level 3 Blas routine.
-- Written on 8-February-1989.
Jack Dongarra, Argonne National Laboratory.
Iain Duff, AERE Harwell.
Jeremy Du Croz, Numerical Algorithms Group Ltd.
Sven Hammarling, Numerical Algorithms Group Ltd.
=====================================================================
Test the input parameters.
Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
b_dim1 = *ldb;
b_offset = 1 + b_dim1;
b -= b_offset;
/* Function Body */
lside = igraphlsame_(side, "L");
if (lside) {
nrowa = *m;
} else {
nrowa = *n;
}
nounit = igraphlsame_(diag, "N");
upper = igraphlsame_(uplo, "U");
info = 0;
if (! lside && ! igraphlsame_(side, "R")) {
info = 1;
} else if (! upper && ! igraphlsame_(uplo, "L")) {
info = 2;
} else if (! igraphlsame_(transa, "N") && ! igraphlsame_(transa,
"T") && ! igraphlsame_(transa, "C")) {
info = 3;
} else if (! igraphlsame_(diag, "U") && ! igraphlsame_(diag,
"N")) {
info = 4;
} else if (*m < 0) {
info = 5;
} else if (*n < 0) {
info = 6;
} else if (*lda < max(1,nrowa)) {
info = 9;
} else if (*ldb < max(1,*m)) {
info = 11;
}
if (info != 0) {
igraphxerbla_("DTRSM ", &info, (ftnlen)6);
return 0;
}
/* Quick return if possible. */
if (*m == 0 || *n == 0) {
return 0;
}
/* And when alpha.eq.zero. */
if (*alpha == 0.) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
b[i__ + j * b_dim1] = 0.;
/* L10: */
}
/* L20: */
}
return 0;
}
/* Start the operations. */
if (lside) {
if (igraphlsame_(transa, "N")) {
/* Form B := alpha*inv( A )*B. */
if (upper) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (*alpha != 1.) {
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
b[i__ + j * b_dim1] = *alpha * b[i__ + j * b_dim1]
;
/* L30: */
}
}
for (k = *m; k >= 1; --k) {
if (b[k + j * b_dim1] != 0.) {
if (nounit) {
b[k + j * b_dim1] /= a[k + k * a_dim1];
}
i__2 = k - 1;
for (i__ = 1; i__ <= i__2; ++i__) {
b[i__ + j * b_dim1] -= b[k + j * b_dim1] * a[
i__ + k * a_dim1];
/* L40: */
}
}
/* L50: */
}
/* L60: */
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (*alpha != 1.) {
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
b[i__ + j * b_dim1] = *alpha * b[i__ + j * b_dim1]
;
/* L70: */
}
}
i__2 = *m;
for (k = 1; k <= i__2; ++k) {
if (b[k + j * b_dim1] != 0.) {
if (nounit) {
b[k + j * b_dim1] /= a[k + k * a_dim1];
}
i__3 = *m;
for (i__ = k + 1; i__ <= i__3; ++i__) {
b[i__ + j * b_dim1] -= b[k + j * b_dim1] * a[
i__ + k * a_dim1];
/* L80: */
}
}
/* L90: */
}
/* L100: */
}
}
} else {
/* Form B := alpha*inv( A**T )*B. */
if (upper) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
temp = *alpha * b[i__ + j * b_dim1];
i__3 = i__ - 1;
for (k = 1; k <= i__3; ++k) {
temp -= a[k + i__ * a_dim1] * b[k + j * b_dim1];
/* L110: */
}
if (nounit) {
temp /= a[i__ + i__ * a_dim1];
}
b[i__ + j * b_dim1] = temp;
/* L120: */
}
/* L130: */
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
for (i__ = *m; i__ >= 1; --i__) {
temp = *alpha * b[i__ + j * b_dim1];
i__2 = *m;
for (k = i__ + 1; k <= i__2; ++k) {
temp -= a[k + i__ * a_dim1] * b[k + j * b_dim1];
/* L140: */
}
if (nounit) {
temp /= a[i__ + i__ * a_dim1];
}
b[i__ + j * b_dim1] = temp;
/* L150: */
}
/* L160: */
}
}
}
} else {
if (igraphlsame_(transa, "N")) {
/* Form B := alpha*B*inv( A ). */
if (upper) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (*alpha != 1.) {
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
b[i__ + j * b_dim1] = *alpha * b[i__ + j * b_dim1]
;
/* L170: */
}
}
i__2 = j - 1;
for (k = 1; k <= i__2; ++k) {
if (a[k + j * a_dim1] != 0.) {
i__3 = *m;
for (i__ = 1; i__ <= i__3; ++i__) {
b[i__ + j * b_dim1] -= a[k + j * a_dim1] * b[
i__ + k * b_dim1];
/* L180: */
}
}
/* L190: */
}
if (nounit) {
temp = 1. / a[j + j * a_dim1];
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
b[i__ + j * b_dim1] = temp * b[i__ + j * b_dim1];
/* L200: */
}
}
/* L210: */
}
} else {
for (j = *n; j >= 1; --j) {
if (*alpha != 1.) {
i__1 = *m;
for (i__ = 1; i__ <= i__1; ++i__) {
b[i__ + j * b_dim1] = *alpha * b[i__ + j * b_dim1]
;
/* L220: */
}
}
i__1 = *n;
for (k = j + 1; k <= i__1; ++k) {
if (a[k + j * a_dim1] != 0.) {
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
b[i__ + j * b_dim1] -= a[k + j * a_dim1] * b[
i__ + k * b_dim1];
/* L230: */
}
}
/* L240: */
}
if (nounit) {
temp = 1. / a[j + j * a_dim1];
i__1 = *m;
for (i__ = 1; i__ <= i__1; ++i__) {
b[i__ + j * b_dim1] = temp * b[i__ + j * b_dim1];
/* L250: */
}
}
/* L260: */
}
}
} else {
/* Form B := alpha*B*inv( A**T ). */
if (upper) {
for (k = *n; k >= 1; --k) {
if (nounit) {
temp = 1. / a[k + k * a_dim1];
i__1 = *m;
for (i__ = 1; i__ <= i__1; ++i__) {
b[i__ + k * b_dim1] = temp * b[i__ + k * b_dim1];
/* L270: */
}
}
i__1 = k - 1;
for (j = 1; j <= i__1; ++j) {
if (a[j + k * a_dim1] != 0.) {
temp = a[j + k * a_dim1];
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
b[i__ + j * b_dim1] -= temp * b[i__ + k *
b_dim1];
/* L280: */
}
}
/* L290: */
}
if (*alpha != 1.) {
i__1 = *m;
for (i__ = 1; i__ <= i__1; ++i__) {
b[i__ + k * b_dim1] = *alpha * b[i__ + k * b_dim1]
;
/* L300: */
}
}
/* L310: */
}
} else {
i__1 = *n;
for (k = 1; k <= i__1; ++k) {
if (nounit) {
temp = 1. / a[k + k * a_dim1];
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
b[i__ + k * b_dim1] = temp * b[i__ + k * b_dim1];
/* L320: */
}
}
i__2 = *n;
for (j = k + 1; j <= i__2; ++j) {
if (a[j + k * a_dim1] != 0.) {
temp = a[j + k * a_dim1];
i__3 = *m;
for (i__ = 1; i__ <= i__3; ++i__) {
b[i__ + j * b_dim1] -= temp * b[i__ + k *
b_dim1];
/* L330: */
}
}
/* L340: */
}
if (*alpha != 1.) {
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
b[i__ + k * b_dim1] = *alpha * b[i__ + k * b_dim1]
;
/* L350: */
}
}
/* L360: */
}
}
}
}
return 0;
/* End of DTRSM . */
} /* igraphdtrsm_ */