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.TH DOPMTR l "15 June 2000" "LAPACK version 3.0" ")"
.SH NAME
DOPMTR - overwrite the general real M-by-N matrix C with SIDE = 'L' SIDE = 'R' TRANS = 'N'
.SH SYNOPSIS
.TP 19
SUBROUTINE DOPMTR(
SIDE, UPLO, TRANS, M, N, AP, TAU, C, LDC, WORK,
INFO )
.TP 19
.ti +4
CHARACTER
SIDE, TRANS, UPLO
.TP 19
.ti +4
INTEGER
INFO, LDC, M, N
.TP 19
.ti +4
DOUBLE
PRECISION AP( * ), C( LDC, * ), TAU( * ), WORK( * )
.SH 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
.br
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:
.br
if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);
.br
if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).
.br
.SH ARGUMENTS
.TP 8
SIDE (input) CHARACTER*1
= 'L': apply Q or Q**T from the Left;
.br
= 'R': apply Q or Q**T from the Right.
.TP 8
UPLO (input) CHARACTER*1
.br
= 'U': Upper triangular packed storage used in previous
call to DSPTRD;
= 'L': Lower triangular packed storage used in previous
call to DSPTRD.
.TP 8
TRANS (input) CHARACTER*1
= 'N': No transpose, apply Q;
.br
= 'T': Transpose, apply Q**T.
.TP 8
M (input) INTEGER
The number of rows of the matrix C. M >= 0.
.TP 8
N (input) INTEGER
The number of columns of the matrix C. N >= 0.
.TP 8
AP (input) 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.
.TP 8
TAU (input) 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.
.TP 8
C (input/output) 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.
.TP 8
LDC (input) INTEGER
The leading dimension of the array C. LDC >= max(1,M).
.TP 8
WORK (workspace) DOUBLE PRECISION array, dimension
(N) if SIDE = 'L'
(M) if SIDE = 'R'
.TP 8
INFO (output) INTEGER
= 0: successful exit
.br
< 0: if INFO = -i, the i-th argument had an illegal value
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