SRC/cunm2l.f(3) Library Functions Manual SRC/cunm2l.f(3)

SRC/cunm2l.f


subroutine cunm2l (side, trans, m, n, k, a, lda, tau, c, ldc, work, info)
CUNM2L multiplies a general matrix by the unitary matrix from a QL factorization determined by cgeqlf (unblocked algorithm).

CUNM2L multiplies a general matrix by the unitary matrix from a QL factorization determined by cgeqlf (unblocked algorithm).

Purpose:

 CUNM2L overwrites the general complex m-by-n matrix C with
       Q * C  if SIDE = 'L' and TRANS = 'N', or
       Q**H* C  if SIDE = 'L' and TRANS = 'C', or
       C * Q  if SIDE = 'R' and TRANS = 'N', or
       C * Q**H if SIDE = 'R' and TRANS = 'C',
 where Q is a complex unitary matrix defined as the product of k
 elementary reflectors
       Q = H(k) . . . H(2) H(1)
 as returned by CGEQLF. 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**H from the Left
          = 'R': apply Q or Q**H from the Right

TRANS

          TRANS is CHARACTER*1
          = 'N': apply Q  (No transpose)
          = 'C': apply Q**H (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.

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

C

          C is COMPLEX 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

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

WORK

          WORK is COMPLEX 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.

Definition at line 157 of file cunm2l.f.

Generated automatically by Doxygen for LAPACK from the source code.

Version 3.12.0 LAPACK