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Mise à jour de lapack vers la version 3.3.0.

    1:       SUBROUTINE ZTRTRS( UPLO, TRANS, DIAG, N, NRHS, A, LDA, B, LDB,
    2:      $                   INFO )
    3: *
    4: *  -- LAPACK routine (version 3.2) --
    5: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
    6: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
    7: *     November 2006
    8: *
    9: *     .. Scalar Arguments ..
   10:       CHARACTER          DIAG, TRANS, UPLO
   11:       INTEGER            INFO, LDA, LDB, N, NRHS
   12: *     ..
   13: *     .. Array Arguments ..
   14:       COMPLEX*16         A( LDA, * ), B( LDB, * )
   15: *     ..
   16: *
   17: *  Purpose
   18: *  =======
   19: *
   20: *  ZTRTRS solves a triangular system of the form
   21: *
   22: *     A * X = B,  A**T * X = B,  or  A**H * X = B,
   23: *
   24: *  where A is a triangular matrix of order N, and B is an N-by-NRHS
   25: *  matrix.  A check is made to verify that A is nonsingular.
   26: *
   27: *  Arguments
   28: *  =========
   29: *
   30: *  UPLO    (input) CHARACTER*1
   31: *          = 'U':  A is upper triangular;
   32: *          = 'L':  A is lower triangular.
   33: *
   34: *  TRANS   (input) CHARACTER*1
   35: *          Specifies the form of the system of equations:
   36: *          = 'N':  A * X = B     (No transpose)
   37: *          = 'T':  A**T * X = B  (Transpose)
   38: *          = 'C':  A**H * X = B  (Conjugate transpose)
   39: *
   40: *  DIAG    (input) CHARACTER*1
   41: *          = 'N':  A is non-unit triangular;
   42: *          = 'U':  A is unit triangular.
   43: *
   44: *  N       (input) INTEGER
   45: *          The order of the matrix A.  N >= 0.
   46: *
   47: *  NRHS    (input) INTEGER
   48: *          The number of right hand sides, i.e., the number of columns
   49: *          of the matrix B.  NRHS >= 0.
   50: *
   51: *  A       (input) COMPLEX*16 array, dimension (LDA,N)
   52: *          The triangular matrix A.  If UPLO = 'U', the leading N-by-N
   53: *          upper triangular part of the array A contains the upper
   54: *          triangular matrix, and the strictly lower triangular part of
   55: *          A is not referenced.  If UPLO = 'L', the leading N-by-N lower
   56: *          triangular part of the array A contains the lower triangular
   57: *          matrix, and the strictly upper triangular part of A is not
   58: *          referenced.  If DIAG = 'U', the diagonal elements of A are
   59: *          also not referenced and are assumed to be 1.
   60: *
   61: *  LDA     (input) INTEGER
   62: *          The leading dimension of the array A.  LDA >= max(1,N).
   63: *
   64: *  B       (input/output) COMPLEX*16 array, dimension (LDB,NRHS)
   65: *          On entry, the right hand side matrix B.
   66: *          On exit, if INFO = 0, the solution matrix X.
   67: *
   68: *  LDB     (input) INTEGER
   69: *          The leading dimension of the array B.  LDB >= max(1,N).
   70: *
   71: *  INFO    (output) INTEGER
   72: *          = 0:  successful exit
   73: *          < 0: if INFO = -i, the i-th argument had an illegal value
   74: *          > 0: if INFO = i, the i-th diagonal element of A is zero,
   75: *               indicating that the matrix is singular and the solutions
   76: *               X have not been computed.
   77: *
   78: *  =====================================================================
   79: *
   80: *     .. Parameters ..
   81:       COMPLEX*16         ZERO, ONE
   82:       PARAMETER          ( ZERO = ( 0.0D+0, 0.0D+0 ),
   83:      $                   ONE = ( 1.0D+0, 0.0D+0 ) )
   84: *     ..
   85: *     .. Local Scalars ..
   86:       LOGICAL            NOUNIT
   87: *     ..
   88: *     .. External Functions ..
   89:       LOGICAL            LSAME
   90:       EXTERNAL           LSAME
   91: *     ..
   92: *     .. External Subroutines ..
   93:       EXTERNAL           XERBLA, ZTRSM
   94: *     ..
   95: *     .. Intrinsic Functions ..
   96:       INTRINSIC          MAX
   97: *     ..
   98: *     .. Executable Statements ..
   99: *
  100: *     Test the input parameters.
  101: *
  102:       INFO = 0
  103:       NOUNIT = LSAME( DIAG, 'N' )
  104:       IF( .NOT.LSAME( UPLO, 'U' ) .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
  105:          INFO = -1
  106:       ELSE IF( .NOT.LSAME( TRANS, 'N' ) .AND. .NOT.
  107:      $         LSAME( TRANS, 'T' ) .AND. .NOT.LSAME( TRANS, 'C' ) ) THEN
  108:          INFO = -2
  109:       ELSE IF( .NOT.NOUNIT .AND. .NOT.LSAME( DIAG, 'U' ) ) THEN
  110:          INFO = -3
  111:       ELSE IF( N.LT.0 ) THEN
  112:          INFO = -4
  113:       ELSE IF( NRHS.LT.0 ) THEN
  114:          INFO = -5
  115:       ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
  116:          INFO = -7
  117:       ELSE IF( LDB.LT.MAX( 1, N ) ) THEN
  118:          INFO = -9
  119:       END IF
  120:       IF( INFO.NE.0 ) THEN
  121:          CALL XERBLA( 'ZTRTRS', -INFO )
  122:          RETURN
  123:       END IF
  124: *
  125: *     Quick return if possible
  126: *
  127:       IF( N.EQ.0 )
  128:      $   RETURN
  129: *
  130: *     Check for singularity.
  131: *
  132:       IF( NOUNIT ) THEN
  133:          DO 10 INFO = 1, N
  134:             IF( A( INFO, INFO ).EQ.ZERO )
  135:      $         RETURN
  136:    10    CONTINUE
  137:       END IF
  138:       INFO = 0
  139: *
  140: *     Solve A * x = b,  A**T * x = b,  or  A**H * x = b.
  141: *
  142:       CALL ZTRSM( 'Left', UPLO, TRANS, DIAG, N, NRHS, ONE, A, LDA, B,
  143:      $            LDB )
  144: *
  145:       RETURN
  146: *
  147: *     End of ZTRTRS
  148: *
  149:       END