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slaset.f
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*> \brief \b SLASET initializes the off-diagonal elements and the diagonal elements of a matrix to given values.
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*
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* =========== DOCUMENTATION ===========
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*
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* Online html documentation available at
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* http://www.netlib.org/lapack/explore-html/
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*
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*> \htmlonly
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*> Download SLASET + dependencies
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slaset.f">
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*> [TGZ]</a>
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slaset.f">
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*> [ZIP]</a>
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slaset.f">
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*> [TXT]</a>
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*> \endhtmlonly
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*
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* Definition:
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* ===========
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*
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* SUBROUTINE SLASET( UPLO, M, N, ALPHA, BETA, A, LDA )
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*
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* .. Scalar Arguments ..
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* CHARACTER UPLO
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* INTEGER LDA, M, N
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* REAL ALPHA, BETA
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* ..
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* .. Array Arguments ..
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* REAL A( LDA, * )
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* ..
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*
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*
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*> \par Purpose:
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* =============
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*>
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*> \verbatim
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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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*> \endverbatim
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*
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* Arguments:
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* ==========
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*
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*> \param[in] UPLO
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*> \verbatim
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*> UPLO is 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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*> \endverbatim
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*>
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*> \param[in] M
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*> \verbatim
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*> M is INTEGER
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*> The number of rows of the matrix A. M >= 0.
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*> \endverbatim
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*>
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*> \param[in] N
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*> \verbatim
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*> N is INTEGER
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*> The number of columns of the matrix A. N >= 0.
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*> \endverbatim
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*>
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*> \param[in] ALPHA
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*> \verbatim
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*> ALPHA is REAL
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*> The constant to which the offdiagonal elements are to be set.
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*> \endverbatim
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*>
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*> \param[in] BETA
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*> \verbatim
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*> BETA is REAL
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*> The constant to which the diagonal elements are to be set.
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*> \endverbatim
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*>
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*> \param[out] A
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*> \verbatim
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*> A is 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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*>
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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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*>
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*> and, for all UPLO, A(i,i) = BETA, 1<=i<=min(m,n).
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*> \endverbatim
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*>
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*> \param[in] LDA
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*> \verbatim
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*> LDA is INTEGER
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*> The leading dimension of the array A. LDA >= max(1,M).
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*> \endverbatim
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*
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* Authors:
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* ========
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*
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*> \author Univ. of Tennessee
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*> \author Univ. of California Berkeley
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*> \author Univ. of Colorado Denver
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*> \author NAG Ltd.
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*
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*> \date December 2016
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*
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*> \ingroup OTHERauxiliary
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*
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* =====================================================================
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SUBROUTINE
slaset
( UPLO, M, N, ALPHA, BETA, A, LDA )
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*
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* -- LAPACK auxiliary routine (version 3.7.0) --
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* -- LAPACK is a software package provided by Univ. of Tennessee, --
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* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
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* December 2016
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*
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* .. Scalar Arguments ..
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CHARACTER
UPLO
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INTEGER
LDA, M, N
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REAL
ALPHA, BETA
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* ..
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* .. Array Arguments ..
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REAL
A( lda, * )
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* ..
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*
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* =====================================================================
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*
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* .. Local Scalars ..
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INTEGER
I, J
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* ..
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* .. External Functions ..
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LOGICAL
LSAME
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EXTERNAL
lsame
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* ..
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* .. Intrinsic Functions ..
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INTRINSIC
min
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* ..
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* .. Executable Statements ..
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*
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IF
( lsame( uplo,
'U'
) )
THEN
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*
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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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*
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DO
20 j = 2, n
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DO
10 i = 1, min( j-1, m )
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a( i, j ) = alpha
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10
CONTINUE
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CONTINUE
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*
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ELSE
IF
( lsame( uplo,
'L'
) )
THEN
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*
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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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*
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DO
40 j = 1, min( m, n )
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DO
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a( i, j ) = alpha
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CONTINUE
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40
CONTINUE
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*
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ELSE
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*
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* Set the leading m-by-n submatrix to ALPHA.
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*
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DO
60 j = 1, n
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DO
50 i = 1, m
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a( i, j ) = alpha
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50
CONTINUE
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60
CONTINUE
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END IF
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*
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* Set the first min(M,N) diagonal elements to BETA.
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*
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DO
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a( i, i ) = beta
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CONTINUE
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*
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RETURN
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*
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* End of SLASET
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*
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END
slaset
subroutine slaset(UPLO, M, N, ALPHA, BETA, A, LDA)
SLASET initializes the off-diagonal elements and the diagonal elements of a matrix to given values...
Definition:
slaset.f:112
SRC
slaset.f
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