📄 dtrmm.c
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#include "f2c.h"
#include "netlib.h"
/* Subroutine */ void dtrmm_(side, uplo, transa, diag, m, n, alpha, a, lda, b, ldb)
const char *side, *uplo, *transa, *diag;
const integer *m, *n;
doublereal *alpha, *a;
const integer *lda;
doublereal *b;
const integer *ldb;
{
/* System generated locals */
integer a_dim1, a_offset, b_dim1, b_offset, i__1, i__2, i__3;
/* Local variables */
static integer info;
static doublereal temp;
static integer i, j, k;
static logical lside;
static integer nrowa;
static logical upper;
static logical nounit;
/* Purpose */
/* ======= */
/* DTRMM performs one of the matrix-matrix operations */
/* B := alpha*op( A )*B, or B := alpha*B*op( A ), */
/* where alpha is a scalar, B is an m by n matrix, 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'. */
/* Parameters */
/* ========== */
/* SIDE - CHARACTER*1. */
/* On entry, SIDE specifies whether op( A ) multiplies B from */
/* the left or right as follows: */
/* SIDE = 'L' or 'l' B := alpha*op( A )*B. */
/* SIDE = 'R' or 'r' B := alpha*B*op( A ). */
/* 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'. */
/* TRANSA = 'C' or 'c' op( A ) = A'. */
/* 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 matrix B, and on exit is overwritten by the */
/* transformed matrix. */
/* 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. */
/* 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. */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1 * 1;
a -= a_offset;
b_dim1 = *ldb;
b_offset = 1 + b_dim1 * 1;
b -= b_offset;
/* Test the input parameters. */
lside = lsame_(side, "L");
if (lside) {
nrowa = *m;
} else {
nrowa = *n;
}
nounit = lsame_(diag, "N");
upper = lsame_(uplo, "U");
info = 0;
if (! lside && ! lsame_(side, "R")) {
info = 1;
} else if (! upper && ! lsame_(uplo, "L")) {
info = 2;
} else if (! lsame_(transa, "N") && ! lsame_(transa, "T") && ! lsame_(transa, "C")) {
info = 3;
} else if (! lsame_(diag, "U") && ! lsame_(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) {
xerbla_("DTRMM ", &info);
return;
}
/* Quick return if possible. */
if (*n == 0) {
return;
}
/* 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.;
}
}
return;
}
/* Start the operations. */
if (lside) {
if (lsame_(transa, "N")) {
/* Form B := alpha*A*B. */
if (upper) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = *m;
for (k = 1; k <= i__2; ++k) {
if (b[k + j * b_dim1] != 0.) {
temp = *alpha * b[k + j * b_dim1];
i__3 = k - 1;
for (i = 1; i <= i__3; ++i) {
b[i + j * b_dim1] += temp * a[i + k * a_dim1];
}
if (nounit) {
temp *= a[k + k * a_dim1];
}
b[k + j * b_dim1] = temp;
}
}
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
for (k = *m; k >= 1; --k) {
if (b[k + j * b_dim1] != 0.) {
temp = *alpha * b[k + j * b_dim1];
b[k + j * b_dim1] = temp;
if (nounit) {
b[k + j * b_dim1] *= a[k + k * a_dim1];
}
i__2 = *m;
for (i = k + 1; i <= i__2; ++i) {
b[i + j * b_dim1] += temp * a[i + k * a_dim1];
}
}
}
}
}
} else {
/* Form B := alpha*A'*B. */
if (upper) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
for (i = *m; i >= 1; --i) {
temp = b[i + j * b_dim1];
if (nounit) {
temp *= a[i + i * a_dim1];
}
i__2 = i - 1;
for (k = 1; k <= i__2; ++k) {
temp += a[k + i * a_dim1] * b[k + j * b_dim1];
}
b[i + j * b_dim1] = *alpha * temp;
}
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = *m;
for (i = 1; i <= i__2; ++i) {
temp = b[i + j * b_dim1];
if (nounit) {
temp *= a[i + i * a_dim1];
}
i__3 = *m;
for (k = i + 1; k <= i__3; ++k) {
temp += a[k + i * a_dim1] * b[k + j * b_dim1];
}
b[i + j * b_dim1] = *alpha * temp;
}
}
}
}
} else {
if (lsame_(transa, "N")) {
/* Form B := alpha*B*A. */
if (upper) {
for (j = *n; j >= 1; --j) {
temp = *alpha;
if (nounit) {
temp *= a[j + j * a_dim1];
}
i__1 = *m;
for (i = 1; i <= i__1; ++i) {
b[i + j * b_dim1] *= temp;
}
i__1 = j - 1;
for (k = 1; k <= i__1; ++k) {
if (a[k + j * a_dim1] != 0.) {
temp = *alpha * a[k + j * a_dim1];
i__2 = *m;
for (i = 1; i <= i__2; ++i) {
b[i + j * b_dim1] += temp * b[i + k * b_dim1];
}
}
}
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
temp = *alpha;
if (nounit) {
temp *= a[j + j * a_dim1];
}
i__2 = *m;
for (i = 1; i <= i__2; ++i) {
b[i + j * b_dim1] *= temp;
}
i__2 = *n;
for (k = j + 1; k <= i__2; ++k) {
if (a[k + j * a_dim1] != 0.) {
temp = *alpha * a[k + j * a_dim1];
i__3 = *m;
for (i = 1; i <= i__3; ++i) {
b[i + j * b_dim1] += temp * b[i + k * b_dim1];
}
}
}
}
}
} else {
/* Form B := alpha*B*A'. */
if (upper) {
i__1 = *n;
for (k = 1; k <= i__1; ++k) {
i__2 = k - 1;
for (j = 1; j <= i__2; ++j) {
if (a[j + k * a_dim1] != 0.) {
temp = *alpha * 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];
}
}
}
temp = *alpha;
if (nounit) {
temp *= a[k + k * a_dim1];
}
if (temp != 1.) {
i__2 = *m;
for (i = 1; i <= i__2; ++i) {
b[i + k * b_dim1] *= temp;
}
}
}
} else {
for (k = *n; k >= 1; --k) {
i__1 = *n;
for (j = k + 1; j <= i__1; ++j) {
if (a[j + k * a_dim1] != 0.) {
temp = *alpha * 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];
}
}
}
temp = *alpha;
if (nounit) {
temp *= a[k + k * a_dim1];
}
if (temp != 1.) {
i__1 = *m;
for (i = 1; i <= i__1; ++i) {
b[i + k * b_dim1] *= temp;
}
}
}
}
}
}
} /* dtrmm_ */
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