dopmtr.f man page

dopmtr.f —

Synopsis

Functions/Subroutines

subroutine dopmtr (SIDE, UPLO, TRANS, M, N, AP, TAU, C, LDC, WORK, INFO)
DOPMTR

Function/Subroutine Documentation

subroutine dopmtr (characterSIDE, characterUPLO, characterTRANS, integerM, integerN, double precision, dimension( * )AP, double precision, dimension( * )TAU, double precision, dimension( ldc, * )C, integerLDC, double precision, dimension( * )WORK, integerINFO)

DOPMTR

Purpose:

DOPMTR overwrites the general real M-by-N matrix C with

                SIDE = 'L'     SIDE = 'R'
TRANS = 'N':      Q * C          C * Q
TRANS = 'T':      Q**T * C       C * Q**T

where Q is a real orthogonal matrix of order nq, with nq = m if
SIDE = 'L' and nq = n if SIDE = 'R'. Q is defined as the product of
nq-1 elementary reflectors, as returned by DSPTRD using packed
storage:

if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);

if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).

Parameters:

SIDE

SIDE is CHARACTER*1
= 'L': apply Q or Q**T from the Left;
= 'R': apply Q or Q**T from the Right.

UPLO

UPLO is CHARACTER*1
= 'U': Upper triangular packed storage used in previous
       call to DSPTRD;
= 'L': Lower triangular packed storage used in previous
       call to DSPTRD.

TRANS

TRANS is CHARACTER*1
= 'N':  No transpose, apply Q;
= 'T':  Transpose, apply Q**T.

M

M is INTEGER
The number of rows of the matrix C. M >= 0.

N

N is INTEGER
The number of columns of the matrix C. N >= 0.

AP

AP is DOUBLE PRECISION array, dimension
                     (M*(M+1)/2) if SIDE = 'L'
                     (N*(N+1)/2) if SIDE = 'R'
The vectors which define the elementary reflectors, as
returned by DSPTRD.  AP is modified by the routine but
restored on exit.

TAU

TAU is DOUBLE PRECISION array, dimension (M-1) if SIDE = 'L'
                           or (N-1) if SIDE = 'R'
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by DSPTRD.

C

C is DOUBLE PRECISION array, dimension (LDC,N)
On entry, the M-by-N matrix C.
On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q.

LDC

LDC is INTEGER
The leading dimension of the array C. LDC >= max(1,M).

WORK

WORK is DOUBLE PRECISION array, dimension
                         (N) if SIDE = 'L'
                         (M) if SIDE = 'R'

INFO

INFO is INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Definition at line 150 of file dopmtr.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

dopmtr(3) is an alias of dopmtr.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK