333 lines
7.7 KiB
C
333 lines
7.7 KiB
C
#include "clapack.h"
|
|
|
|
/* Subroutine */ int strmv_(char *uplo, char *trans, char *diag, integer *n,
|
|
real *a, integer *lda, real *x, integer *incx)
|
|
{
|
|
/* System generated locals */
|
|
integer a_dim1, a_offset, i__1, i__2;
|
|
|
|
/* Local variables */
|
|
integer i__, j, ix, jx, kx, info;
|
|
real temp;
|
|
extern logical lsame_(char *, char *);
|
|
extern /* Subroutine */ int xerbla_(char *, integer *);
|
|
logical nounit;
|
|
|
|
/* .. Scalar Arguments .. */
|
|
/* .. */
|
|
/* .. Array Arguments .. */
|
|
/* .. */
|
|
|
|
/* Purpose */
|
|
/* ======= */
|
|
|
|
/* STRMV performs one of the matrix-vector operations */
|
|
|
|
/* x := A*x, or x := A'*x, */
|
|
|
|
/* where x is an n element vector and A is an n by n unit, or non-unit, */
|
|
/* upper or lower triangular matrix. */
|
|
|
|
/* Arguments */
|
|
/* ========== */
|
|
|
|
/* UPLO - CHARACTER*1. */
|
|
/* On entry, UPLO specifies whether the matrix 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. */
|
|
|
|
/* TRANS - CHARACTER*1. */
|
|
/* On entry, TRANS specifies the operation to be performed as */
|
|
/* follows: */
|
|
|
|
/* TRANS = 'N' or 'n' x := A*x. */
|
|
|
|
/* TRANS = 'T' or 't' x := A'*x. */
|
|
|
|
/* TRANS = 'C' or 'c' x := A'*x. */
|
|
|
|
/* 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. */
|
|
|
|
/* N - INTEGER. */
|
|
/* On entry, N specifies the order of the matrix A. */
|
|
/* N must be at least zero. */
|
|
/* Unchanged on exit. */
|
|
|
|
/* A - REAL array of DIMENSION ( LDA, n ). */
|
|
/* Before entry with UPLO = 'U' or 'u', the leading n by n */
|
|
/* 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 n by n */
|
|
/* 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. LDA must be at least */
|
|
/* max( 1, n ). */
|
|
/* Unchanged on exit. */
|
|
|
|
/* X - REAL array of dimension at least */
|
|
/* ( 1 + ( n - 1 )*abs( INCX ) ). */
|
|
/* Before entry, the incremented array X must contain the n */
|
|
/* element vector x. On exit, X is overwritten with the */
|
|
/* tranformed vector x. */
|
|
|
|
/* INCX - INTEGER. */
|
|
/* On entry, INCX specifies the increment for the elements of */
|
|
/* X. INCX must not be zero. */
|
|
/* Unchanged on exit. */
|
|
|
|
|
|
/* Level 2 Blas routine. */
|
|
|
|
/* -- Written on 22-October-1986. */
|
|
/* Jack Dongarra, Argonne National Lab. */
|
|
/* Jeremy Du Croz, Nag Central Office. */
|
|
/* Sven Hammarling, Nag Central Office. */
|
|
/* Richard Hanson, Sandia National Labs. */
|
|
|
|
|
|
/* .. Parameters .. */
|
|
/* .. */
|
|
/* .. Local Scalars .. */
|
|
/* .. */
|
|
/* .. External Functions .. */
|
|
/* .. */
|
|
/* .. External Subroutines .. */
|
|
/* .. */
|
|
/* .. Intrinsic Functions .. */
|
|
/* .. */
|
|
|
|
/* Test the input parameters. */
|
|
|
|
/* Parameter adjustments */
|
|
a_dim1 = *lda;
|
|
a_offset = 1 + a_dim1;
|
|
a -= a_offset;
|
|
--x;
|
|
|
|
/* Function Body */
|
|
info = 0;
|
|
if (! lsame_(uplo, "U") && ! lsame_(uplo, "L")) {
|
|
info = 1;
|
|
} else if (! lsame_(trans, "N") && ! lsame_(trans,
|
|
"T") && ! lsame_(trans, "C")) {
|
|
info = 2;
|
|
} else if (! lsame_(diag, "U") && ! lsame_(diag,
|
|
"N")) {
|
|
info = 3;
|
|
} else if (*n < 0) {
|
|
info = 4;
|
|
} else if (*lda < max(1,*n)) {
|
|
info = 6;
|
|
} else if (*incx == 0) {
|
|
info = 8;
|
|
}
|
|
if (info != 0) {
|
|
xerbla_("STRMV ", &info);
|
|
return 0;
|
|
}
|
|
|
|
/* Quick return if possible. */
|
|
|
|
if (*n == 0) {
|
|
return 0;
|
|
}
|
|
|
|
nounit = lsame_(diag, "N");
|
|
|
|
/* Set up the start point in X if the increment is not unity. This */
|
|
/* will be ( N - 1 )*INCX too small for descending loops. */
|
|
|
|
if (*incx <= 0) {
|
|
kx = 1 - (*n - 1) * *incx;
|
|
} else if (*incx != 1) {
|
|
kx = 1;
|
|
}
|
|
|
|
/* Start the operations. In this version the elements of A are */
|
|
/* accessed sequentially with one pass through A. */
|
|
|
|
if (lsame_(trans, "N")) {
|
|
|
|
/* Form x := A*x. */
|
|
|
|
if (lsame_(uplo, "U")) {
|
|
if (*incx == 1) {
|
|
i__1 = *n;
|
|
for (j = 1; j <= i__1; ++j) {
|
|
if (x[j] != 0.f) {
|
|
temp = x[j];
|
|
i__2 = j - 1;
|
|
for (i__ = 1; i__ <= i__2; ++i__) {
|
|
x[i__] += temp * a[i__ + j * a_dim1];
|
|
/* L10: */
|
|
}
|
|
if (nounit) {
|
|
x[j] *= a[j + j * a_dim1];
|
|
}
|
|
}
|
|
/* L20: */
|
|
}
|
|
} else {
|
|
jx = kx;
|
|
i__1 = *n;
|
|
for (j = 1; j <= i__1; ++j) {
|
|
if (x[jx] != 0.f) {
|
|
temp = x[jx];
|
|
ix = kx;
|
|
i__2 = j - 1;
|
|
for (i__ = 1; i__ <= i__2; ++i__) {
|
|
x[ix] += temp * a[i__ + j * a_dim1];
|
|
ix += *incx;
|
|
/* L30: */
|
|
}
|
|
if (nounit) {
|
|
x[jx] *= a[j + j * a_dim1];
|
|
}
|
|
}
|
|
jx += *incx;
|
|
/* L40: */
|
|
}
|
|
}
|
|
} else {
|
|
if (*incx == 1) {
|
|
for (j = *n; j >= 1; --j) {
|
|
if (x[j] != 0.f) {
|
|
temp = x[j];
|
|
i__1 = j + 1;
|
|
for (i__ = *n; i__ >= i__1; --i__) {
|
|
x[i__] += temp * a[i__ + j * a_dim1];
|
|
/* L50: */
|
|
}
|
|
if (nounit) {
|
|
x[j] *= a[j + j * a_dim1];
|
|
}
|
|
}
|
|
/* L60: */
|
|
}
|
|
} else {
|
|
kx += (*n - 1) * *incx;
|
|
jx = kx;
|
|
for (j = *n; j >= 1; --j) {
|
|
if (x[jx] != 0.f) {
|
|
temp = x[jx];
|
|
ix = kx;
|
|
i__1 = j + 1;
|
|
for (i__ = *n; i__ >= i__1; --i__) {
|
|
x[ix] += temp * a[i__ + j * a_dim1];
|
|
ix -= *incx;
|
|
/* L70: */
|
|
}
|
|
if (nounit) {
|
|
x[jx] *= a[j + j * a_dim1];
|
|
}
|
|
}
|
|
jx -= *incx;
|
|
/* L80: */
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
|
|
/* Form x := A'*x. */
|
|
|
|
if (lsame_(uplo, "U")) {
|
|
if (*incx == 1) {
|
|
for (j = *n; j >= 1; --j) {
|
|
temp = x[j];
|
|
if (nounit) {
|
|
temp *= a[j + j * a_dim1];
|
|
}
|
|
for (i__ = j - 1; i__ >= 1; --i__) {
|
|
temp += a[i__ + j * a_dim1] * x[i__];
|
|
/* L90: */
|
|
}
|
|
x[j] = temp;
|
|
/* L100: */
|
|
}
|
|
} else {
|
|
jx = kx + (*n - 1) * *incx;
|
|
for (j = *n; j >= 1; --j) {
|
|
temp = x[jx];
|
|
ix = jx;
|
|
if (nounit) {
|
|
temp *= a[j + j * a_dim1];
|
|
}
|
|
for (i__ = j - 1; i__ >= 1; --i__) {
|
|
ix -= *incx;
|
|
temp += a[i__ + j * a_dim1] * x[ix];
|
|
/* L110: */
|
|
}
|
|
x[jx] = temp;
|
|
jx -= *incx;
|
|
/* L120: */
|
|
}
|
|
}
|
|
} else {
|
|
if (*incx == 1) {
|
|
i__1 = *n;
|
|
for (j = 1; j <= i__1; ++j) {
|
|
temp = x[j];
|
|
if (nounit) {
|
|
temp *= a[j + j * a_dim1];
|
|
}
|
|
i__2 = *n;
|
|
for (i__ = j + 1; i__ <= i__2; ++i__) {
|
|
temp += a[i__ + j * a_dim1] * x[i__];
|
|
/* L130: */
|
|
}
|
|
x[j] = temp;
|
|
/* L140: */
|
|
}
|
|
} else {
|
|
jx = kx;
|
|
i__1 = *n;
|
|
for (j = 1; j <= i__1; ++j) {
|
|
temp = x[jx];
|
|
ix = jx;
|
|
if (nounit) {
|
|
temp *= a[j + j * a_dim1];
|
|
}
|
|
i__2 = *n;
|
|
for (i__ = j + 1; i__ <= i__2; ++i__) {
|
|
ix += *incx;
|
|
temp += a[i__ + j * a_dim1] * x[ix];
|
|
/* L150: */
|
|
}
|
|
x[jx] = temp;
|
|
jx += *incx;
|
|
/* L160: */
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
|
|
/* End of STRMV . */
|
|
|
|
} /* strmv_ */
|