Return to zpotri.f CVS log

Up to [local] / rpl / lapack / lapack

Première mise à jour de lapack et blas.

    1: *> \brief \b ZPOTRI
    2: *
    3: *  =========== DOCUMENTATION ===========
    4: *
    5: * Online html documentation available at
    6: *            http://www.netlib.org/lapack/explore-html/
    7: *
    8: *> \htmlonly
    9: *> Download ZPOTRI + dependencies
   10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zpotri.f">
   11: *> [TGZ]</a>
   12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zpotri.f">
   13: *> [ZIP]</a>
   14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zpotri.f">
   15: *> [TXT]</a>
   16: *> \endhtmlonly
   17: *
   18: *  Definition:
   19: *  ===========
   20: *
   21: *       SUBROUTINE ZPOTRI( UPLO, N, A, LDA, INFO )
   22: *
   23: *       .. Scalar Arguments ..
   24: *       CHARACTER          UPLO
   25: *       INTEGER            INFO, LDA, N
   26: *       ..
   27: *       .. Array Arguments ..
   28: *       COMPLEX*16         A( LDA, * )
   29: *       ..
   30: *
   31: *
   32: *> \par Purpose:
   33: *  =============
   34: *>
   35: *> \verbatim
   36: *>
   37: *> ZPOTRI computes the inverse of a complex Hermitian positive definite
   38: *> matrix A using the Cholesky factorization A = U**H*U or A = L*L**H
   39: *> computed by ZPOTRF.
   40: *> \endverbatim
   41: *
   42: *  Arguments:
   43: *  ==========
   44: *
   45: *> \param[in] UPLO
   46: *> \verbatim
   47: *>          UPLO is CHARACTER*1
   48: *>          = 'U':  Upper triangle of A is stored;
   49: *>          = 'L':  Lower triangle of A is stored.
   50: *> \endverbatim
   51: *>
   52: *> \param[in] N
   53: *> \verbatim
   54: *>          N is INTEGER
   55: *>          The order of the matrix A.  N >= 0.
   56: *> \endverbatim
   57: *>
   58: *> \param[in,out] A
   59: *> \verbatim
   60: *>          A is COMPLEX*16 array, dimension (LDA,N)
   61: *>          On entry, the triangular factor U or L from the Cholesky
   62: *>          factorization A = U**H*U or A = L*L**H, as computed by
   63: *>          ZPOTRF.
   64: *>          On exit, the upper or lower triangle of the (Hermitian)
   65: *>          inverse of A, overwriting the input factor U or L.
   66: *> \endverbatim
   67: *>
   68: *> \param[in] LDA
   69: *> \verbatim
   70: *>          LDA is INTEGER
   71: *>          The leading dimension of the array A.  LDA >= max(1,N).
   72: *> \endverbatim
   73: *>
   74: *> \param[out] INFO
   75: *> \verbatim
   76: *>          INFO is INTEGER
   77: *>          = 0:  successful exit
   78: *>          < 0:  if INFO = -i, the i-th argument had an illegal value
   79: *>          > 0:  if INFO = i, the (i,i) element of the factor U or L is
   80: *>                zero, and the inverse could not be computed.
   81: *> \endverbatim
   82: *
   83: *  Authors:
   84: *  ========
   85: *
   86: *> \author Univ. of Tennessee
   87: *> \author Univ. of California Berkeley
   88: *> \author Univ. of Colorado Denver
   89: *> \author NAG Ltd.
   90: *
   91: *> \ingroup complex16POcomputational
   92: *
   93: *  =====================================================================
   94:       SUBROUTINE ZPOTRI( UPLO, N, A, LDA, INFO )
   95: *
   96: *  -- LAPACK computational routine --
   97: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
   98: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
   99: *
  100: *     .. Scalar Arguments ..
  101:       CHARACTER          UPLO
  102:       INTEGER            INFO, LDA, N
  103: *     ..
  104: *     .. Array Arguments ..
  105:       COMPLEX*16         A( LDA, * )
  106: *     ..
  107: *
  108: *  =====================================================================
  109: *
  110: *     .. External Functions ..
  111:       LOGICAL            LSAME
  112:       EXTERNAL           LSAME
  113: *     ..
  114: *     .. External Subroutines ..
  115:       EXTERNAL           XERBLA, ZLAUUM, ZTRTRI
  116: *     ..
  117: *     .. Intrinsic Functions ..
  118:       INTRINSIC          MAX
  119: *     ..
  120: *     .. Executable Statements ..
  121: *
  122: *     Test the input parameters.
  123: *
  124:       INFO = 0
  125:       IF( .NOT.LSAME( UPLO, 'U' ) .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
  126:          INFO = -1
  127:       ELSE IF( N.LT.0 ) THEN
  128:          INFO = -2
  129:       ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
  130:          INFO = -4
  131:       END IF
  132:       IF( INFO.NE.0 ) THEN
  133:          CALL XERBLA( 'ZPOTRI', -INFO )
  134:          RETURN
  135:       END IF
  136: *
  137: *     Quick return if possible
  138: *
  139:       IF( N.EQ.0 )
  140:      $   RETURN
  141: *
  142: *     Invert the triangular Cholesky factor U or L.
  143: *
  144:       CALL ZTRTRI( UPLO, 'Non-unit', N, A, LDA, INFO )
  145:       IF( INFO.GT.0 )
  146:      $   RETURN
  147: *
  148: *     Form inv(U) * inv(U)**H or inv(L)**H * inv(L).
  149: *
  150:       CALL ZLAUUM( UPLO, N, A, LDA, INFO )
  151: *
  152:       RETURN
  153: *
  154: *     End of ZPOTRI
  155: *
  156:       END