181 lines
4.2 KiB
C
181 lines
4.2 KiB
C
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/* -- translated by f2c (version 19940927).
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You must link the resulting object file with the libraries:
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-lf2c -lm (in that order)
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*/
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#include "f2c.h"
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/* Subroutine */ int sger_(integer *m, integer *n, real *alpha, real *x,
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integer *incx, real *y, integer *incy, real *a, integer *lda)
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{
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/* System generated locals */
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integer a_dim1, a_offset, i__1, i__2;
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/* Local variables */
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static integer info;
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static real temp;
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static integer i, j, ix, jy, kx;
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extern /* Subroutine */ int xerbla_(char *, integer *);
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/* Purpose
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=======
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SGER performs the rank 1 operation
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A := alpha*x*y' + A,
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where alpha is a scalar, x is an m element vector, y is an n element
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vector and A is an m by n matrix.
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Parameters
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==========
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M - INTEGER.
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On entry, M specifies the number of rows of the matrix A.
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M must be at least zero.
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Unchanged on exit.
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N - INTEGER.
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On entry, N specifies the number of columns of the matrix A.
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N must be at least zero.
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Unchanged on exit.
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ALPHA - REAL .
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On entry, ALPHA specifies the scalar alpha.
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Unchanged on exit.
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X - REAL array of dimension at least
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( 1 + ( m - 1 )*abs( INCX ) ).
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Before entry, the incremented array X must contain the m
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element vector x.
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Unchanged on exit.
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INCX - INTEGER.
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On entry, INCX specifies the increment for the elements of
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X. INCX must not be zero.
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Unchanged on exit.
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Y - REAL array of dimension at least
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( 1 + ( n - 1 )*abs( INCY ) ).
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Before entry, the incremented array Y must contain the n
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element vector y.
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Unchanged on exit.
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INCY - INTEGER.
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On entry, INCY specifies the increment for the elements of
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Y. INCY must not be zero.
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Unchanged on exit.
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A - REAL array of DIMENSION ( LDA, n ).
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Before entry, the leading m by n part of the array A must
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contain the matrix of coefficients. On exit, A is
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overwritten by the updated matrix.
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LDA - INTEGER.
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On entry, LDA specifies the first dimension of A as declared
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in the calling (sub) program. LDA must be at least
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max( 1, m ).
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Unchanged on exit.
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Level 2 Blas routine.
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-- Written on 22-October-1986.
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Jack Dongarra, Argonne National Lab.
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Jeremy Du Croz, Nag Central Office.
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Sven Hammarling, Nag Central Office.
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Richard Hanson, Sandia National Labs.
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Test the input parameters.
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Parameter adjustments
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Function Body */
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#define X(I) x[(I)-1]
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#define Y(I) y[(I)-1]
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#define A(I,J) a[(I)-1 + ((J)-1)* ( *lda)]
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info = 0;
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if (*m < 0) {
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info = 1;
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} else if (*n < 0) {
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info = 2;
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} else if (*incx == 0) {
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info = 5;
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} else if (*incy == 0) {
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info = 7;
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} else if (*lda < max(1,*m)) {
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info = 9;
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}
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if (info != 0) {
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xerbla_("SGER ", &info);
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return 0;
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}
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/* Quick return if possible. */
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if (*m == 0 || *n == 0 || *alpha == 0.f) {
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return 0;
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}
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/* Start the operations. In this version the elements of A are
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accessed sequentially with one pass through A. */
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if (*incy > 0) {
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jy = 1;
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} else {
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jy = 1 - (*n - 1) * *incy;
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}
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if (*incx == 1) {
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i__1 = *n;
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for (j = 1; j <= *n; ++j) {
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if (Y(jy) != 0.f) {
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temp = *alpha * Y(jy);
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i__2 = *m;
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for (i = 1; i <= *m; ++i) {
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A(i,j) += X(i) * temp;
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/* L10: */
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}
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}
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jy += *incy;
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/* L20: */
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}
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} else {
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if (*incx > 0) {
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kx = 1;
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} else {
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kx = 1 - (*m - 1) * *incx;
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}
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i__1 = *n;
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for (j = 1; j <= *n; ++j) {
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if (Y(jy) != 0.f) {
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temp = *alpha * Y(jy);
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ix = kx;
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i__2 = *m;
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for (i = 1; i <= *m; ++i) {
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A(i,j) += X(ix) * temp;
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ix += *incx;
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/* L30: */
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}
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}
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jy += *incy;
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/* L40: */
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}
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}
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return 0;
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/* End of SGER . */
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} /* sger_ */
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