SORMR3(3S)SORMR3(3S)NAMESORMR3 - overwrite the general real m by n matrix C with Q * C if SIDE =
'L' and TRANS = 'N', or Q'* C if SIDE = 'L' and TRANS = 'T', or C * Q
if SIDE = 'R' and TRANS = 'N', or C * Q' if SIDE = 'R' and TRANS = 'T',
SYNOPSIS
SUBROUTINE SORMR3( SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC, WORK,
INFO )
CHARACTER SIDE, TRANS
INTEGER INFO, K, L, LDA, LDC, M, N
REAL A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )
IMPLEMENTATION
These routines are part of the SCSL Scientific Library and can be loaded
using either the -lscs or the -lscs_mp option. The -lscs_mp option
directs the linker to use the multi-processor version of the library.
When linking to SCSL with -lscs or -lscs_mp, the default integer size is
4 bytes (32 bits). Another version of SCSL is available in which integers
are 8 bytes (64 bits). This version allows the user access to larger
memory sizes and helps when porting legacy Cray codes. It can be loaded
by using the -lscs_i8 option or the -lscs_i8_mp option. A program may use
only one of the two versions; 4-byte integer and 8-byte integer library
calls cannot be mixed.
PURPOSESORMR3 overwrites the general real m by n matrix C with Q * C if SIDE =
'L' and TRANS = 'N', or Q'* C if SIDE = 'L' and TRANS = 'T', or C * Q if
SIDE = 'R' and TRANS = 'N', or C * Q' 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 STZRZF. Q is of order m if SIDE = 'L' and of order n if
SIDE = 'R'.
ARGUMENTS
SIDE (input) CHARACTER*1
= 'L': apply Q or Q' from the Left
= 'R': apply Q or Q' from the Right
TRANS (input) CHARACTER*1
= 'N': apply Q (No transpose)
= 'T': apply Q' (Transpose)
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SORMR3(3S)SORMR3(3S)
M (input) INTEGER
The number of rows of the matrix C. M >= 0.
N (input) INTEGER
The number of columns of the matrix C. N >= 0.
K (input) INTEGER
The number of elementary reflectors whose product defines the
matrix Q. If SIDE = 'L', M >= K >= 0; if SIDE = 'R', N >= K >=
0.
L (input) INTEGER
The number of columns of the matrix A containing the meaningful
part of the Householder reflectors. If SIDE = 'L', M >= L >= 0,
if SIDE = 'R', N >= L >= 0.
A (input) REAL 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 STZRZF in the last k rows of
its array argument A. A is modified by the routine but restored
on exit.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1,K).
TAU (input) REAL array, dimension (K)
TAU(i) must contain the scalar factor of the elementary reflector
H(i), as returned by STZRZF.
C (input/output) REAL array, dimension (LDC,N)
On entry, the m-by-n matrix C. On exit, C is overwritten by Q*C
or Q'*C or C*Q' or C*Q.
LDC (input) INTEGER
The leading dimension of the array C. LDC >= max(1,M).
WORK (workspace) REAL array, dimension
(N) if SIDE = 'L', (M) if SIDE = 'R'
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
FURTHER DETAILS
Based on contributions by
A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA
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SORMR3(3S)SORMR3(3S)SEE ALSOINTRO_LAPACK(3S), INTRO_SCSL(3S)
This man page is available only online.
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