Contact
Impressum
Why this name?
pdf

sorm22.f

NAME

sorm22.f −

SYNOPSIS

Functions/Subroutines

subroutine sorm22 (SIDE, TRANS, M, N, N1, N2, Q, LDQ, C, LDC, WORK, LWORK, INFO)
SORM22
multiplies a general matrix by a banded orthogonal matrix.

Function/Subroutine Documentation

subroutine sorm22 (character SIDE, character TRANS, integer M, integer N, integer N1, integer N2, real, dimension( ldq, * ) Q, integer LDQ, real, dimension( ldc, * ) C, integer LDC, real, dimension( * ) WORK, integer LWORK, integer INFO)
SORM22
multiplies a general matrix by a banded orthogonal matrix.

Purpose

SORM22 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’.
The orthogonal matrix Q processes a 2-by-2 block structure

[ Q11 Q12 ]
Q = [ ]
[ Q21 Q22 ],

where Q12 is an N1-by-N1 lower triangular matrix and Q21 is an
N2-by-N2 upper triangular matrix.

Parameters:

SIDE

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

TRANS

TRANS is CHARACTER*1
= ’N’: apply Q (No transpose);
= ’C’: apply Q**T (Conjugate transpose).

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.

N1
N2

N1 is INTEGER
N2 is INTEGER
The dimension of Q12 and Q21, respectively. N1, N2 >= 0.
The following requirement must be satisfied:
N1 + N2 = M if SIDE = ’L’ and N1 + N2 = N if SIDE = ’R’.

Q

Q is REAL array, dimension
(LDQ,M) if SIDE = ’L’
(LDQ,N) if SIDE = ’R’

LDQ

LDQ is INTEGER
The leading dimension of the array Q.
LDQ >= max(1,M) if SIDE = ’L’; LDQ >= max(1,N) if SIDE = ’R’.

C

C is REAL 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 REAL array, dimension (MAX(1,LWORK))
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

LWORK

LWORK is INTEGER
The dimension of the array WORK.
If SIDE = ’L’, LWORK >= max(1,N);
if SIDE = ’R’, LWORK >= max(1,M).
For optimum performance LWORK >= M*N.

If LWORK = -1, then a workspace query is assumed; the routine
only calculates the optimal size of the WORK array, returns
this value as the first entry of the WORK array, and no error
message related to LWORK is issued by XERBLA.

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:

January 2015

Author

Generated automatically by Doxygen for LAPACK from the source code.

pdf
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

No Banana Union - No Software Patents