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Mise à jour globale de Lapack 3.2.2.

    1:       SUBROUTINE ZPOTRS( UPLO, N, NRHS, A, LDA, B, LDB, INFO )
    2: *
    3: *  -- LAPACK routine (version 3.2) --
    4: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
    5: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
    6: *     November 2006
    7: *
    8: *     .. Scalar Arguments ..
    9:       CHARACTER          UPLO
   10:       INTEGER            INFO, LDA, LDB, N, NRHS
   11: *     ..
   12: *     .. Array Arguments ..
   13:       COMPLEX*16         A( LDA, * ), B( LDB, * )
   14: *     ..
   15: *
   16: *  Purpose
   17: *  =======
   18: *
   19: *  ZPOTRS solves a system of linear equations A*X = B with a Hermitian
   20: *  positive definite matrix A using the Cholesky factorization
   21: *  A = U**H*U or A = L*L**H computed by ZPOTRF.
   22: *
   23: *  Arguments
   24: *  =========
   25: *
   26: *  UPLO    (input) CHARACTER*1
   27: *          = 'U':  Upper triangle of A is stored;
   28: *          = 'L':  Lower triangle of A is stored.
   29: *
   30: *  N       (input) INTEGER
   31: *          The order of the matrix A.  N >= 0.
   32: *
   33: *  NRHS    (input) INTEGER
   34: *          The number of right hand sides, i.e., the number of columns
   35: *          of the matrix B.  NRHS >= 0.
   36: *
   37: *  A       (input) COMPLEX*16 array, dimension (LDA,N)
   38: *          The triangular factor U or L from the Cholesky factorization
   39: *          A = U**H*U or A = L*L**H, as computed by ZPOTRF.
   40: *
   41: *  LDA     (input) INTEGER
   42: *          The leading dimension of the array A.  LDA >= max(1,N).
   43: *
   44: *  B       (input/output) COMPLEX*16 array, dimension (LDB,NRHS)
   45: *          On entry, the right hand side matrix B.
   46: *          On exit, the solution matrix X.
   47: *
   48: *  LDB     (input) INTEGER
   49: *          The leading dimension of the array B.  LDB >= max(1,N).
   50: *
   51: *  INFO    (output) INTEGER
   52: *          = 0:  successful exit
   53: *          < 0:  if INFO = -i, the i-th argument had an illegal value
   54: *
   55: *  =====================================================================
   56: *
   57: *     .. Parameters ..
   58:       COMPLEX*16         ONE
   59:       PARAMETER          ( ONE = ( 1.0D+0, 0.0D+0 ) )
   60: *     ..
   61: *     .. Local Scalars ..
   62:       LOGICAL            UPPER
   63: *     ..
   64: *     .. External Functions ..
   65:       LOGICAL            LSAME
   66:       EXTERNAL           LSAME
   67: *     ..
   68: *     .. External Subroutines ..
   69:       EXTERNAL           XERBLA, ZTRSM
   70: *     ..
   71: *     .. Intrinsic Functions ..
   72:       INTRINSIC          MAX
   73: *     ..
   74: *     .. Executable Statements ..
   75: *
   76: *     Test the input parameters.
   77: *
   78:       INFO = 0
   79:       UPPER = LSAME( UPLO, 'U' )
   80:       IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
   81:          INFO = -1
   82:       ELSE IF( N.LT.0 ) THEN
   83:          INFO = -2
   84:       ELSE IF( NRHS.LT.0 ) THEN
   85:          INFO = -3
   86:       ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
   87:          INFO = -5
   88:       ELSE IF( LDB.LT.MAX( 1, N ) ) THEN
   89:          INFO = -7
   90:       END IF
   91:       IF( INFO.NE.0 ) THEN
   92:          CALL XERBLA( 'ZPOTRS', -INFO )
   93:          RETURN
   94:       END IF
   95: *
   96: *     Quick return if possible
   97: *
   98:       IF( N.EQ.0 .OR. NRHS.EQ.0 )
   99:      $   RETURN
  100: *
  101:       IF( UPPER ) THEN
  102: *
  103: *        Solve A*X = B where A = U'*U.
  104: *
  105: *        Solve U'*X = B, overwriting B with X.
  106: *
  107:          CALL ZTRSM( 'Left', 'Upper', 'Conjugate transpose', 'Non-unit',
  108:      $               N, NRHS, ONE, A, LDA, B, LDB )
  109: *
  110: *        Solve U*X = B, overwriting B with X.
  111: *
  112:          CALL ZTRSM( 'Left', 'Upper', 'No transpose', 'Non-unit', N,
  113:      $               NRHS, ONE, A, LDA, B, LDB )
  114:       ELSE
  115: *
  116: *        Solve A*X = B where A = L*L'.
  117: *
  118: *        Solve L*X = B, overwriting B with X.
  119: *
  120:          CALL ZTRSM( 'Left', 'Lower', 'No transpose', 'Non-unit', N,
  121:      $               NRHS, ONE, A, LDA, B, LDB )
  122: *
  123: *        Solve L'*X = B, overwriting B with X.
  124: *
  125:          CALL ZTRSM( 'Left', 'Lower', 'Conjugate transpose', 'Non-unit',
  126:      $               N, NRHS, ONE, A, LDA, B, LDB )
  127:       END IF
  128: *
  129:       RETURN
  130: *
  131: *     End of ZPOTRS
  132: *
  133:       END