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116 lines
2.8 KiB
116 lines
2.8 KiB
*> \brief \b SLARSCL2 performs reciprocal diagonal scaling on a matrix.
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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 SLARSCL2 + dependencies
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slarscl2.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/slarscl2.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/slarscl2.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 SLARSCL2 ( M, N, D, X, LDX )
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*
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* .. Scalar Arguments ..
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* INTEGER M, N, LDX
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* ..
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* .. Array Arguments ..
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* REAL D( * ), X( LDX, * )
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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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*> SLARSCL2 performs a reciprocal diagonal scaling on a matrix:
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*> x <-- inv(D) * x
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*> where the diagonal matrix D is stored as a vector.
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*>
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*> Eventually to be replaced by BLAS_sge_diag_scale in the new BLAS
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*> standard.
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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] M
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*> \verbatim
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*> M is INTEGER
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*> The number of rows of D and X. 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 X. N >= 0.
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*> \endverbatim
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*>
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*> \param[in] D
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*> \verbatim
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*> D is REAL array, length M
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*> Diagonal matrix D, stored as a vector of length M.
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*> \endverbatim
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*>
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*> \param[in,out] X
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*> \verbatim
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*> X is REAL array, dimension (LDX,N)
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*> On entry, the matrix X to be scaled by D.
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*> On exit, the scaled matrix.
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*> \endverbatim
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*>
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*> \param[in] LDX
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*> \verbatim
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*> LDX is INTEGER
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*> The leading dimension of the matrix X. LDX >= 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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*> \ingroup realOTHERcomputational
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*
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* =====================================================================
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SUBROUTINE SLARSCL2 ( M, N, D, X, LDX )
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*
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* -- LAPACK computational routine --
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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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*
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* .. Scalar Arguments ..
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INTEGER M, N, LDX
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* ..
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* .. Array Arguments ..
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REAL D( * ), X( LDX, * )
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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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* .. Executable Statements ..
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*
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DO J = 1, N
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DO I = 1, M
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X( I, J ) = X( I, J ) / D( I )
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END DO
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END DO
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RETURN
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END
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