redhat man page for sormrz

SORMRZ(l)								 )								 SORMRZ(l)

NAME
       SORMRZ - overwrite the general real M-by-N matrix C with  SIDE = 'L' SIDE = 'R' TRANS = 'N'

SYNOPSIS
       SUBROUTINE SORMRZ( SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC, WORK, LWORK, INFO )

	   CHARACTER	  SIDE, TRANS

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

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

PURPOSE
       SORMRZ 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 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**T from the Left;
	       = 'R': apply Q or Q**T from the Right.

       TRANS   (input) CHARACTER*1
	       = 'N':  No transpose, apply Q;
	       = 'T':  Transpose, apply Q**T.

       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**H*C or C*Q**H or C*Q.

       LDC     (input) INTEGER
	       The leading dimension of the array C. LDC >= max(1,M).

       WORK    (workspace/output) REAL array, dimension (LWORK)
	       On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

       LWORK   (input) 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 >= N*NB if SIDE = 'L', and LWORK >= M*NB if SIDE = 'R', where NB is the optimal blocksize.

	       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    (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

LAPACK version 3.0						   15 June 2000 							 SORMRZ(l)