BLAS/SRC/dtrmv.f(3)

NAME
BLAS/SRC/dtrmv.f

SYNOPSIS

  Functions/Subroutines
subroutine dtrmv (uplo, trans, diag, n, a, lda, x, incx)
DTRMV

Function/Subroutine Documentation

  subroutine dtrmv (character uplo, character trans, character diag, integer n, double precision, dimension(lda,*) a, integer lda, double precision, dimension(*) x, integer incx)

DTRMV

Purpose:

     DTRMV  performs one of the matrix-vector operations
        x := A*x,   or   x := A**T*x,
     where x is an n element vector and  A is an n by n unit, or non-unit,
     upper or lower triangular matrix.

Parameters
    UPLO

              UPLO is 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.

    TRANS

              TRANS is CHARACTER*1
               On entry, TRANS specifies the operation to be performed as
               follows:
                  TRANS = 'N' or 'n'   x := A*x.
                  TRANS = 'T' or 't'   x := A**T*x.
                  TRANS = 'C' or 'c'   x := A**T*x.

    DIAG

              DIAG is CHARACTER*1
               On entry, DIAG specifies whether or not A is unit
               triangular as follows:
                  DIAG = 'U' or 'u'   A is assumed to be unit triangular.
                  DIAG = 'N' or 'n'   A is not assumed to be unit
                                      triangular.

    N

              N is INTEGER
               On entry, N specifies the order of the matrix A.
               N must be at least zero.

    A

              A is DOUBLE PRECISION array, dimension ( LDA, N )
               Before entry with  UPLO = 'U' or 'u', the leading n by n
               upper triangular part of the array A must contain the upper
               triangular matrix and the strictly lower triangular part of
               A is not referenced.
               Before entry with UPLO = 'L' or 'l', the leading n by n
               lower triangular part of the array A must contain the lower
               triangular matrix and the strictly upper triangular part of
               A is not referenced.
               Note that when  DIAG = 'U' or 'u', the diagonal elements of
               A are not referenced either, but are assumed to be unity.

    LDA

              LDA is 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 ).

    X

              X is DOUBLE PRECISION array, dimension at least
               ( 1 + ( n - 1 )*abs( INCX ) ).
               Before entry, the incremented array X must contain the n
               element vector x. On exit, X is overwritten with the
               transformed vector x.

    INCX

              INCX is INTEGER
               On entry, INCX specifies the increment for the elements of
               X. INCX must not be zero.

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Further Details:

      Level 2 Blas routine.
      The vector and matrix arguments are not referenced when N = 0, or M = 0
      -- Written on 22-October-1986.
         Jack Dongarra, Argonne National Lab.
         Jeremy Du Croz, Nag Central Office.
         Sven Hammarling, Nag Central Office.
         Richard Hanson, Sandia National Labs.

Definition at line 146 of file dtrmv.f.

Author

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