140 lines
3.5 KiB
C
140 lines
3.5 KiB
C
#include "clapack.h"
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/* Subroutine */ int slaset_(char *uplo, integer *m, integer *n, real *alpha,
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real *beta, 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, i__3;
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/* Local variables */
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integer i__, j;
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extern logical lsame_(char *, char *);
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/* -- LAPACK auxiliary routine (version 3.1) -- */
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/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
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/* November 2006 */
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/* .. Scalar Arguments .. */
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/* .. */
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/* .. Array Arguments .. */
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/* .. */
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/* Purpose */
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/* ======= */
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/* SLASET initializes an m-by-n matrix A to BETA on the diagonal and */
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/* ALPHA on the offdiagonals. */
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/* Arguments */
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/* ========= */
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/* UPLO (input) CHARACTER*1 */
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/* Specifies the part of the matrix A to be set. */
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/* = 'U': Upper triangular part is set; the strictly lower */
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/* triangular part of A is not changed. */
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/* = 'L': Lower triangular part is set; the strictly upper */
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/* triangular part of A is not changed. */
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/* Otherwise: All of the matrix A is set. */
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/* M (input) INTEGER */
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/* The number of rows of the matrix A. M >= 0. */
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/* N (input) INTEGER */
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/* The number of columns of the matrix A. N >= 0. */
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/* ALPHA (input) REAL */
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/* The constant to which the offdiagonal elements are to be set. */
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/* BETA (input) REAL */
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/* The constant to which the diagonal elements are to be set. */
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/* A (input/output) REAL array, dimension (LDA,N) */
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/* On exit, the leading m-by-n submatrix of A is set as follows: */
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/* if UPLO = 'U', A(i,j) = ALPHA, 1<=i<=j-1, 1<=j<=n, */
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/* if UPLO = 'L', A(i,j) = ALPHA, j+1<=i<=m, 1<=j<=n, */
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/* otherwise, A(i,j) = ALPHA, 1<=i<=m, 1<=j<=n, i.ne.j, */
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/* and, for all UPLO, A(i,i) = BETA, 1<=i<=min(m,n). */
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/* LDA (input) INTEGER */
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/* The leading dimension of the array A. LDA >= max(1,M). */
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/* ===================================================================== */
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/* .. Local Scalars .. */
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/* .. */
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/* .. External Functions .. */
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/* .. */
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/* .. Intrinsic Functions .. */
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/* .. */
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/* .. Executable Statements .. */
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/* Parameter adjustments */
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a_dim1 = *lda;
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a_offset = 1 + a_dim1;
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a -= a_offset;
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/* Function Body */
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if (lsame_(uplo, "U")) {
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/* Set the strictly upper triangular or trapezoidal part of the */
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/* array to ALPHA. */
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i__1 = *n;
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for (j = 2; j <= i__1; ++j) {
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/* Computing MIN */
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i__3 = j - 1;
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i__2 = min(i__3,*m);
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for (i__ = 1; i__ <= i__2; ++i__) {
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a[i__ + j * a_dim1] = *alpha;
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/* L10: */
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}
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/* L20: */
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}
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} else if (lsame_(uplo, "L")) {
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/* Set the strictly lower triangular or trapezoidal part of the */
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/* array to ALPHA. */
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i__1 = min(*m,*n);
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for (j = 1; j <= i__1; ++j) {
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i__2 = *m;
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for (i__ = j + 1; i__ <= i__2; ++i__) {
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a[i__ + j * a_dim1] = *alpha;
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/* L30: */
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}
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/* L40: */
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}
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} else {
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/* Set the leading m-by-n submatrix to ALPHA. */
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i__1 = *n;
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for (j = 1; j <= i__1; ++j) {
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i__2 = *m;
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for (i__ = 1; i__ <= i__2; ++i__) {
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a[i__ + j * a_dim1] = *alpha;
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/* L50: */
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}
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/* L60: */
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}
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}
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/* Set the first min(M,N) diagonal elements to BETA. */
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i__1 = min(*m,*n);
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for (i__ = 1; i__ <= i__1; ++i__) {
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a[i__ + i__ * a_dim1] = *beta;
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/* L70: */
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}
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return 0;
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/* End of SLASET */
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} /* slaset_ */
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