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sorml2.f(3) LAPACK sorml2.f(3)

NAME

sorml2.f -

SYNOPSIS

Functions/Subroutines


subroutine sorml2 (SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, INFO)
 
SORML2 multiplies a general matrix by the orthogonal matrix from a LQ factorization determined by sgelqf (unblocked algorithm).

Function/Subroutine Documentation

subroutine sorml2 (characterSIDE, characterTRANS, integerM, integerN, integerK, real, dimension( lda, * )A, integerLDA, real, dimension( * )TAU, real, dimension( ldc, * )C, integerLDC, real, dimension( * )WORK, integerINFO)

SORML2 multiplies a general matrix by the orthogonal matrix from a LQ factorization determined by sgelqf (unblocked algorithm).
Purpose:
 SORML2 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 SGELQF. 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,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
          SGELQF in the first k rows 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. LDA >= max(1,K).
TAU
          TAU is REAL array, dimension (K)
          TAU(i) must contain the scalar factor of the elementary
          reflector H(i), as returned by SGELQF.
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 sorml2.f.

Author

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