132 lines
3.2 KiB
C
132 lines
3.2 KiB
C
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#include "f2c.h"
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/* Subroutine */ int dlaset_(char *uplo, integer *m, integer *n, doublereal *
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alpha, doublereal *beta, doublereal *a, integer *lda)
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{
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/* -- LAPACK auxiliary routine (version 2.0) --
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Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
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Courant Institute, Argonne National Lab, and Rice University
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October 31, 1992
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Purpose
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=======
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DLASET 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) DOUBLE PRECISION
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The constant to which the offdiagonal elements are to be set.
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BETA (input) DOUBLE PRECISION
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The constant to which the diagonal elements are to be set.
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A (input/output) DOUBLE PRECISION 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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Function Body */
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/* System generated locals */
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integer i__1, i__2, i__3;
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/* Local variables */
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static integer i, j;
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extern logical lsame_(char *, char *);
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#define A(I,J) a[(I)-1 + ((J)-1)* ( *lda)]
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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 <= *n; ++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 <= min(j-1,*m); ++i) {
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A(i,j) = *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 <= min(*m,*n); ++j) {
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i__2 = *m;
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for (i = j + 1; i <= *m; ++i) {
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A(i,j) = *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 <= *n; ++j) {
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i__2 = *m;
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for (i = 1; i <= *m; ++i) {
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A(i,j) = *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 <= min(*m,*n); ++i) {
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A(i,i) = *beta;
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/* L70: */
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}
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return 0;
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/* End of DLASET */
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} /* dlaset_ */
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