182 lines
4.7 KiB
Fortran
182 lines
4.7 KiB
Fortran
*> \brief \b SLASET initializes the off-diagonal elements and the diagonal elements of a matrix to given values.
|
|
*
|
|
* =========== DOCUMENTATION ===========
|
|
*
|
|
* Online html documentation available at
|
|
* http://www.netlib.org/lapack/explore-html/
|
|
*
|
|
*> \htmlonly
|
|
*> Download SLASET + dependencies
|
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slaset.f">
|
|
*> [TGZ]</a>
|
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slaset.f">
|
|
*> [ZIP]</a>
|
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slaset.f">
|
|
*> [TXT]</a>
|
|
*> \endhtmlonly
|
|
*
|
|
* Definition:
|
|
* ===========
|
|
*
|
|
* SUBROUTINE SLASET( UPLO, M, N, ALPHA, BETA, A, LDA )
|
|
*
|
|
* .. Scalar Arguments ..
|
|
* CHARACTER UPLO
|
|
* INTEGER LDA, M, N
|
|
* REAL ALPHA, BETA
|
|
* ..
|
|
* .. Array Arguments ..
|
|
* REAL A( LDA, * )
|
|
* ..
|
|
*
|
|
*
|
|
*> \par Purpose:
|
|
* =============
|
|
*>
|
|
*> \verbatim
|
|
*>
|
|
*> SLASET initializes an m-by-n matrix A to BETA on the diagonal and
|
|
*> ALPHA on the offdiagonals.
|
|
*> \endverbatim
|
|
*
|
|
* Arguments:
|
|
* ==========
|
|
*
|
|
*> \param[in] UPLO
|
|
*> \verbatim
|
|
*> UPLO is 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.
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] M
|
|
*> \verbatim
|
|
*> M is INTEGER
|
|
*> The number of rows of the matrix A. M >= 0.
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] N
|
|
*> \verbatim
|
|
*> N is INTEGER
|
|
*> The number of columns of the matrix A. N >= 0.
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] ALPHA
|
|
*> \verbatim
|
|
*> ALPHA is REAL
|
|
*> The constant to which the offdiagonal elements are to be set.
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] BETA
|
|
*> \verbatim
|
|
*> BETA is REAL
|
|
*> The constant to which the diagonal elements are to be set.
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[out] A
|
|
*> \verbatim
|
|
*> A is REAL 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).
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] LDA
|
|
*> \verbatim
|
|
*> LDA is INTEGER
|
|
*> The leading dimension of the array A. LDA >= max(1,M).
|
|
*> \endverbatim
|
|
*
|
|
* Authors:
|
|
* ========
|
|
*
|
|
*> \author Univ. of Tennessee
|
|
*> \author Univ. of California Berkeley
|
|
*> \author Univ. of Colorado Denver
|
|
*> \author NAG Ltd.
|
|
*
|
|
*> \ingroup OTHERauxiliary
|
|
*
|
|
* =====================================================================
|
|
SUBROUTINE SLASET( UPLO, M, N, ALPHA, BETA, A, LDA )
|
|
*
|
|
* -- LAPACK auxiliary routine --
|
|
* -- LAPACK is a software package provided by Univ. of Tennessee, --
|
|
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
|
|
*
|
|
* .. Scalar Arguments ..
|
|
CHARACTER UPLO
|
|
INTEGER LDA, M, N
|
|
REAL ALPHA, BETA
|
|
* ..
|
|
* .. Array Arguments ..
|
|
REAL A( LDA, * )
|
|
* ..
|
|
*
|
|
* =====================================================================
|
|
*
|
|
* .. Local Scalars ..
|
|
INTEGER I, J
|
|
* ..
|
|
* .. External Functions ..
|
|
LOGICAL LSAME
|
|
EXTERNAL LSAME
|
|
* ..
|
|
* .. Intrinsic Functions ..
|
|
INTRINSIC MIN
|
|
* ..
|
|
* .. Executable Statements ..
|
|
*
|
|
IF( LSAME( UPLO, 'U' ) ) THEN
|
|
*
|
|
* Set the strictly upper triangular or trapezoidal part of the
|
|
* array to ALPHA.
|
|
*
|
|
DO 20 J = 2, N
|
|
DO 10 I = 1, MIN( J-1, M )
|
|
A( I, J ) = ALPHA
|
|
10 CONTINUE
|
|
20 CONTINUE
|
|
*
|
|
ELSE IF( LSAME( UPLO, 'L' ) ) THEN
|
|
*
|
|
* Set the strictly lower triangular or trapezoidal part of the
|
|
* array to ALPHA.
|
|
*
|
|
DO 40 J = 1, MIN( M, N )
|
|
DO 30 I = J + 1, M
|
|
A( I, J ) = ALPHA
|
|
30 CONTINUE
|
|
40 CONTINUE
|
|
*
|
|
ELSE
|
|
*
|
|
* Set the leading m-by-n submatrix to ALPHA.
|
|
*
|
|
DO 60 J = 1, N
|
|
DO 50 I = 1, M
|
|
A( I, J ) = ALPHA
|
|
50 CONTINUE
|
|
60 CONTINUE
|
|
END IF
|
|
*
|
|
* Set the first min(M,N) diagonal elements to BETA.
|
|
*
|
|
DO 70 I = 1, MIN( M, N )
|
|
A( I, I ) = BETA
|
|
70 CONTINUE
|
|
*
|
|
RETURN
|
|
*
|
|
* End of SLASET
|
|
*
|
|
END
|