140 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			140 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
#include "clapack.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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    /* 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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/*  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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/*     .. 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 DLASET */
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} /* dlaset_ */
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