SORM2R(3f)

NAME
SORM2R - 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 SORM2R(
    SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, INFO )

CHARACTER
    SIDE, TRANS

INTEGER
    INFO, K, LDA, LDC, M, N

REAL
    A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )

PURPOSE
SORM2R overwrites the general real m by n matrix C with 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 SGEQRF. 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)

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.

A       (input) 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 SGEQRF in the first k columns 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. If SIDE = 'L', LDA >= max(1,M); if SIDE = 'R', LDA >= max(1,N).

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

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