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    1: *> \brief \b DLARSCL2 performs reciprocal diagonal scaling on a matrix.
    2: *
    3: *  =========== DOCUMENTATION ===========
    4: *
    5: * Online html documentation available at
    6: *            http://www.netlib.org/lapack/explore-html/
    7: *
    8: *> \htmlonly
    9: *> Download DLARSCL2 + dependencies
   10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlarscl2.f">
   11: *> [TGZ]</a>
   12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlarscl2.f">
   13: *> [ZIP]</a>
   14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlarscl2.f">
   15: *> [TXT]</a>
   16: *> \endhtmlonly
   17: *
   18: *  Definition:
   19: *  ===========
   20: *
   21: *       SUBROUTINE DLARSCL2 ( M, N, D, X, LDX )
   22: *
   23: *       .. Scalar Arguments ..
   24: *       INTEGER            M, N, LDX
   25: *       ..
   26: *       .. Array Arguments ..
   27: *       DOUBLE PRECISION   D( * ), X( LDX, * )
   28: *       ..
   29: *
   30: *
   31: *> \par Purpose:
   32: *  =============
   33: *>
   34: *> \verbatim
   35: *>
   36: *> DLARSCL2 performs a reciprocal diagonal scaling on a matrix:
   37: *>   x <-- inv(D) * x
   38: *> where the diagonal matrix D is stored as a vector.
   39: *>
   40: *> Eventually to be replaced by BLAS_dge_diag_scale in the new BLAS
   41: *> standard.
   42: *> \endverbatim
   43: *
   44: *  Arguments:
   45: *  ==========
   46: *
   47: *> \param[in] M
   48: *> \verbatim
   49: *>          M is INTEGER
   50: *>     The number of rows of D and X. M >= 0.
   51: *> \endverbatim
   52: *>
   53: *> \param[in] N
   54: *> \verbatim
   55: *>          N is INTEGER
   56: *>     The number of columns of X. N >= 0.
   57: *> \endverbatim
   58: *>
   59: *> \param[in] D
   60: *> \verbatim
   61: *>          D is DOUBLE PRECISION array, dimension (M)
   62: *>     Diagonal matrix D, stored as a vector of length M.
   63: *> \endverbatim
   64: *>
   65: *> \param[in,out] X
   66: *> \verbatim
   67: *>          X is DOUBLE PRECISION array, dimension (LDX,N)
   68: *>     On entry, the matrix X to be scaled by D.
   69: *>     On exit, the scaled matrix.
   70: *> \endverbatim
   71: *>
   72: *> \param[in] LDX
   73: *> \verbatim
   74: *>          LDX is INTEGER
   75: *>     The leading dimension of the matrix X. LDX >= M.
   76: *> \endverbatim
   77: *
   78: *  Authors:
   79: *  ========
   80: *
   81: *> \author Univ. of Tennessee
   82: *> \author Univ. of California Berkeley
   83: *> \author Univ. of Colorado Denver
   84: *> \author NAG Ltd.
   85: *
   86: *> \ingroup doubleOTHERcomputational
   87: *
   88: *  =====================================================================
   89:       SUBROUTINE DLARSCL2 ( M, N, D, X, LDX )
   90: *
   91: *  -- LAPACK computational routine --
   92: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
   93: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
   94: *
   95: *     .. Scalar Arguments ..
   96:       INTEGER            M, N, LDX
   97: *     ..
   98: *     .. Array Arguments ..
   99:       DOUBLE PRECISION   D( * ), X( LDX, * )
  100: *     ..
  101: *
  102: *  =====================================================================
  103: *
  104: *     .. Local Scalars ..
  105:       INTEGER            I, J
  106: *     ..
  107: *     .. Executable Statements ..
  108: *
  109:       DO J = 1, N
  110:          DO I = 1, M
  111:             X( I, J ) = X( I, J ) / D( I )
  112:          END DO
  113:       END DO
  114: 
  115:       RETURN
  116:       END