dormr2.f (3) - Linux Manuals
NAME
dormr2.f -
SYNOPSIS
Functions/Subroutines
subroutine dormr2 (SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, INFO)
DORMR2 multiplies a general matrix by the orthogonal matrix from a RQ factorization determined by sgerqf (unblocked algorithm).
Function/Subroutine Documentation
subroutine dormr2 (characterSIDE, characterTRANS, integerM, integerN, integerK, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( * )TAU, double precision, dimension( ldc, * )C, integerLDC, double precision, dimension( * )WORK, integerINFO)
DORMR2 multiplies a general matrix by the orthogonal matrix from a RQ factorization determined by sgerqf (unblocked algorithm).
Purpose:
-
DORMR2 overwrites the general real m by n matrix C with Q * C if SIDE = 'L' and TRANS = 'N', or Q**T* C if SIDE = 'L' and TRANS = 'T', or C * Q if SIDE = 'R' and TRANS = 'N', or C * Q**T if SIDE = 'R' and TRANS = 'T', where Q is a real orthogonal matrix defined as the product of k elementary reflectors Q = H(1) H(2) . . . H(k) as returned by DGERQF. Q is of order m if SIDE = 'L' and of order n if SIDE = 'R'.
Parameters:
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SIDE
SIDE is CHARACTER*1 = 'L': apply Q or Q**T from the Left = 'R': apply Q or Q**T from the Right
TRANSTRANS is CHARACTER*1 = 'N': apply Q (No transpose) = 'T': apply Q' (Transpose)
MM is INTEGER The number of rows of the matrix C. M >= 0.
NN is INTEGER The number of columns of the matrix C. N >= 0.
KK is INTEGER The number of elementary reflectors whose product defines the matrix Q. If SIDE = 'L', M >= K >= 0; if SIDE = 'R', N >= K >= 0.
AA is DOUBLE PRECISION array, dimension (LDA,M) if SIDE = 'L', (LDA,N) if SIDE = 'R' The i-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by DGERQF in the last k rows of its array argument A. A is modified by the routine but restored on exit.
LDALDA is INTEGER The leading dimension of the array A. LDA >= max(1,K).
TAUTAU is DOUBLE PRECISION array, dimension (K) TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by DGERQF.
CC 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.
LDCLDC is INTEGER The leading dimension of the array C. LDC >= max(1,M).
WORKWORK is DOUBLE PRECISION array, dimension (N) if SIDE = 'L', (M) if SIDE = 'R'
INFOINFO 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:
- September 2012
Definition at line 159 of file dormr2.f.
Author
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