opencv/3rdparty/lapack/dger.c

182 lines
4.4 KiB
C

#include "clapack.h"
/* Subroutine */ int dger_(integer *m, integer *n, doublereal *alpha,
doublereal *x, integer *incx, doublereal *y, integer *incy,
doublereal *a, integer *lda)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2;
/* Local variables */
integer i__, j, ix, jy, kx, info;
doublereal temp;
extern /* Subroutine */ int xerbla_(char *, integer *);
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* DGER performs the rank 1 operation */
/* A := alpha*x*y' + A, */
/* where alpha is a scalar, x is an m element vector, y is an n element */
/* vector and A is an m by n matrix. */
/* Arguments */
/* ========== */
/* M - INTEGER. */
/* On entry, M specifies the number of rows of the matrix A. */
/* M must be at least zero. */
/* Unchanged on exit. */
/* N - INTEGER. */
/* On entry, N specifies the number of columns of the matrix A. */
/* N must be at least zero. */
/* Unchanged on exit. */
/* ALPHA - DOUBLE PRECISION. */
/* On entry, ALPHA specifies the scalar alpha. */
/* Unchanged on exit. */
/* X - DOUBLE PRECISION array of dimension at least */
/* ( 1 + ( m - 1 )*abs( INCX ) ). */
/* Before entry, the incremented array X must contain the m */
/* element vector x. */
/* Unchanged on exit. */
/* INCX - INTEGER. */
/* On entry, INCX specifies the increment for the elements of */
/* X. INCX must not be zero. */
/* Unchanged on exit. */
/* Y - DOUBLE PRECISION array of dimension at least */
/* ( 1 + ( n - 1 )*abs( INCY ) ). */
/* Before entry, the incremented array Y must contain the n */
/* element vector y. */
/* Unchanged on exit. */
/* INCY - INTEGER. */
/* On entry, INCY specifies the increment for the elements of */
/* Y. INCY must not be zero. */
/* Unchanged on exit. */
/* A - DOUBLE PRECISION array of DIMENSION ( LDA, n ). */
/* Before entry, the leading m by n part of the array A must */
/* contain the matrix of coefficients. On exit, A is */
/* overwritten by the updated matrix. */
/* 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, m ). */
/* 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 Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* Test the input parameters. */
/* Parameter adjustments */
--x;
--y;
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
/* Function Body */
info = 0;
if (*m < 0) {
info = 1;
} else if (*n < 0) {
info = 2;
} else if (*incx == 0) {
info = 5;
} else if (*incy == 0) {
info = 7;
} else if (*lda < max(1,*m)) {
info = 9;
}
if (info != 0) {
xerbla_("DGER ", &info);
return 0;
}
/* Quick return if possible. */
if (*m == 0 || *n == 0 || *alpha == 0.) {
return 0;
}
/* Start the operations. In this version the elements of A are */
/* accessed sequentially with one pass through A. */
if (*incy > 0) {
jy = 1;
} else {
jy = 1 - (*n - 1) * *incy;
}
if (*incx == 1) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (y[jy] != 0.) {
temp = *alpha * y[jy];
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
a[i__ + j * a_dim1] += x[i__] * temp;
/* L10: */
}
}
jy += *incy;
/* L20: */
}
} else {
if (*incx > 0) {
kx = 1;
} else {
kx = 1 - (*m - 1) * *incx;
}
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (y[jy] != 0.) {
temp = *alpha * y[jy];
ix = kx;
i__2 = *m;
for (i__ = 1; i__ <= i__2; ++i__) {
a[i__ + j * a_dim1] += x[ix] * temp;
ix += *incx;
/* L30: */
}
}
jy += *incy;
/* L40: */
}
}
return 0;
/* End of DGER . */
} /* dger_ */