dlaset.c

InsightToolkit-1.4.0(有大量的优化算法程序)

#include "f2c.h"
#include "netlib.h"

/* Subroutine */ void dlaset_(const char *uplo, const integer *m, const integer *n,
                    doublereal *alpha, doublereal *beta, doublereal *a, const integer *lda)
{
    /* Local variables */
    static integer i, j;

/*  -- LAPACK auxiliary routine (version 2.0) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., */
/*     Courant Institute, Argonne National Lab, and Rice University */
/*     October 31, 1992 */

/*  Purpose                                                              */
/*  =======                                                              */
/*                                                                       */
/*  DLASET initializes an m-by-n matrix A to BETA on the diagonal and    */
/*  ALPHA on the offdiagonals.                                           */
/*                                                                       */
/*  Arguments                                                            */
/*  =========                                                            */
/*                                                                       */
/*  UPLO    (input) CHARACTER*1                                          */
/*          Specifies the part of the matrix A to be set.                */
/*          = 'U':      Upper triangular part is set; the strictly lower */
/*                      triangular part of A is not changed.             */
/*          = 'L':      Lower triangular part is set; the strictly upper */
/*                      triangular part of A is not changed.             */
/*          Otherwise:  All of the matrix A is set.                      */
/*                                                                       */
/*  M       (input) INTEGER                                              */
/*          The number of rows of the matrix A.  M >= 0.                 */
/*                                                                       */
/*  N       (input) INTEGER                                              */
/*          The number of columns of the matrix A.  N >= 0.              */
/*                                                                       */
/*  ALPHA   (input) DOUBLE PRECISION                                     */
/*          The constant to which the offdiagonal elements are to be set.*/
/*                                                                       */
/*  BETA    (input) DOUBLE PRECISION                                     */
/*          The constant to which the diagonal elements are to be set.   */
/*                                                                       */
/*  A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)     */
/*          On exit, the leading m-by-n submatrix of A is set as follows:*/
/*                                                                       */
/*          if UPLO = 'U', A(i,j) = ALPHA, 1<=i<=j-1, 1<=j<=n,           */
/*          if UPLO = 'L', A(i,j) = ALPHA, j+1<=i<=m, 1<=j<=n,           */
/*          otherwise,     A(i,j) = ALPHA, 1<=i<=m, 1<=j<=n, i.ne.j,     */
/*                                                                       */
/*          and, for all UPLO, A(i,i) = BETA, 1<=i<=min(m,n).            */
/*                                                                       */
/*  LDA     (input) INTEGER                                              */
/*          The leading dimension of the array A.  LDA >= max(1,M).      */
/*                                                                       */
/* ===================================================================== */

    if (lsame_(uplo, "U")) {

/*        Set the strictly upper triangular or trapezoidal part of the */
/*        array to ALPHA. */

        for (j = 1; j < *n; ++j) {
            for (i = 0; i < j && i < *m; ++i) {
                a[i + j * *lda] = *alpha;
            }
        }

    } else if (lsame_(uplo, "L")) {

/*        Set the strictly lower triangular or trapezoidal part of the */
/*        array to ALPHA. */

        for (j = 0; j < *m && j < *n; ++j) {
            for (i = j + 1; i < *m; ++i) {
                a[i + j * *lda] = *alpha;
            }
        }

    } else {

/*        Set the leading m-by-n submatrix to ALPHA. */

        for (j = 0; j < *n; ++j) {
            for (i = 0; i < *m; ++i) {
                a[i + j * *lda] = *alpha;
            }
        }
    }

/*     Set the first min(M,N) diagonal elements to BETA. */

    for (i = 0; i < *m && i < *n; ++i) {
        a[i + i * *lda] = *beta;
    }
} /* dlaset_ */