sorm2l.f man page

sorm2l.f —

Synopsis

Functions/Subroutines

subroutine sorm2l (SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, INFO)
SORM2L multiplies a general matrix by the orthogonal matrix from a QL factorization determined by sgeqlf (unblocked algorithm).

Function/Subroutine Documentation

subroutine sorm2l (characterSIDE, characterTRANS, integerM, integerN, integerK, real, dimension( lda, * )A, integerLDA, real, dimension( * )TAU, real, dimension( ldc, * )C, integerLDC, real, dimension( * )WORK, integerINFO)

SORM2L multiplies a general matrix by the orthogonal matrix from a QL factorization determined by sgeqlf (unblocked algorithm).

Purpose:

SORM2L 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(k) . . . H(2) H(1)

as returned by SGEQLF. Q is of order m if SIDE = 'L' and of order n
if SIDE = 'R'.

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)
= 'T': apply Q**T (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.

K

K 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.

A

A is REAL array, dimension (LDA,K)
The i-th column must contain the vector which defines the
elementary reflector H(i), for i = 1,2,...,k, as returned by
SGEQLF in the last k columns of its array argument A.
A is modified by the routine but restored on exit.

LDA

LDA is INTEGER
The leading dimension of the array A.
If SIDE = 'L', LDA >= max(1,M);
if SIDE = 'R', LDA >= max(1,N).

TAU

TAU is REAL array, dimension (K)
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by SGEQLF.

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
                         (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:

September 2012

Definition at line 159 of file sorm2l.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

sorm2l(3) is an alias of sorm2l.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK