DragonFly On-Line Manual Pages

DTRMVT(l)                              )                             DTRMVT(l)

NAME
       DTRMVT - perform the matrix-vector operations  x := T' *y, and w := T
       *z,

SYNOPSIS
       SUBROUTINE DTRMVT( UPLO, N, T, LDT, X, INCX, Y, INCY, W, INCW, Z, INCZ
                          )
           CHARACTER UPLO
           INTEGER INCW, INCX, INCY, INCZ, LDT, N
           DOUBLE PRECISION T( LDT, * ), W( * ), X( * ), Y( * ), Z( * )

PURPOSE
       DTRMVT performs the matrix-vector operations x := T' *y, and w := T *z,
       where x is an n element vector and  T is an n by n
       upper or lower triangular matrix.

ARGUMENTS
       UPLO   - CHARACTER*1.
              On entry, UPLO specifies whether the matrix is an upper or lower
              triangular matrix as follows:

              UPLO = 'U' or 'u'   A is an upper triangular matrix.

              UPLO = 'L' or 'l'   A is a lower triangular matrix.

              Unchanged on exit.

       N      - INTEGER.
              On entry, N specifies the order of the matrix A.  N must be at
              least zero.  Unchanged on exit.

       T      - DOUBLE PRECISION array of DIMENSION ( LDT, n ).
              Before entry with  UPLO = 'U' or 'u', the leading n by n upper
              triangular part of the array T must contain the upper triangular
              matrix and the strictly lower triangular part of T is not
              referenced.  Before entry with UPLO = 'L' or 'l', the leading n
              by n lower triangular part of the array T must contain the lower
              triangular matrix and the strictly upper triangular part of T is
              not referenced.

       LDT    - INTEGER.
              On entry, LDA specifies the first dimension of A as declared in
              the calling (sub) program. LDA must be at least max( 1, n ).
              Unchanged on exit.

       X      - DOUBLE PRECISION array of dimension at least
              ( 1 + ( n - 1 )*abs( INCX ) ).  On exit, X = T' * y

       INCX   - INTEGER.
              On entry, INCX specifies the increment for the elements of X.
              INCX must not be zero.  Unchanged on exit.

       Y      - DOUBLE PRECISION array of dimension at least
              ( 1 + ( n - 1 )*abs( INCY ) ).  Before entry, the incremented
              array Y must contain the n element vector y.  Unchanged on exit.

       INCY   - INTEGER.
              On entry, INCY specifies the increment for the elements of Y.
              INCY must not be zero.  Unchanged on exit.

       W      - DOUBLE PRECISION array of dimension at least
              ( 1 + ( n - 1 )*abs( INCW ) ).  On exit, W = T * z

       INCW   - INTEGER.
              On entry, INCW specifies the increment for the elements of W.
              INCW must not be zero.  Unchanged on exit.

       Z      - DOUBLE PRECISION array of dimension at least
              ( 1 + ( n - 1 )*abs( INCZ ) ).  Before entry, the incremented
              array Z must contain the n element vector z.  Unchanged on exit.

       INCY   - INTEGER.
              On entrz, INCY specifies the increment for the elements of Y.
              INCY must not be zero.  Unchanged on exit.

              Level 2 Blas routine.

              Test the input parameters.

              Quick return if possible.

              End of DTRMVT.

ScaLAPACK version 1.7           13 August 2001                       DTRMVT(l)