dtpmv (3)  Linux Manuals
NAME
dtpmv.f 
SYNOPSIS
Functions/Subroutines
subroutine dtpmv (UPLO, TRANS, DIAG, N, AP, X, INCX)
DTPMV
Function/Subroutine Documentation
subroutine dtpmv (characterUPLO, characterTRANS, characterDIAG, integerN, double precision, dimension(*)AP, double precision, dimension(*)X, integerINCX)
DTPMV Purpose:

DTPMV performs one of the matrixvector 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 nonunit, upper or lower triangular matrix, supplied in packed form.
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.
TRANSTRANS 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.
DIAGDIAG 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.
NN is INTEGER On entry, N specifies the order of the matrix A. N must be at least zero.
APAP is DOUBLE PRECISION array of DIMENSION at least ( ( n*( n + 1 ) )/2 ). Before entry with UPLO = 'U' or 'u', the array AP must contain the upper triangular matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 ) and a( 2, 2 ) respectively, and so on. Before entry with UPLO = 'L' or 'l', the array AP must contain the lower triangular matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 ) and a( 3, 1 ) respectively, and so on. Note that when DIAG = 'U' or 'u', the diagonal elements of A are not referenced, but are assumed to be unity.
XX is DOUBLE PRECISION array of 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 tranformed vector x.
INCXINCX 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.
Date:
 November 2011
Further Details:

Level 2 Blas routine. The vector and matrix arguments are not referenced when N = 0, or M = 0  Written on 22October1986. Jack Dongarra, Argonne National Lab. Jeremy Du Croz, Nag Central Office. Sven Hammarling, Nag Central Office. Richard Hanson, Sandia National Labs.
Definition at line 143 of file dtpmv.f.
Author
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