cunm22.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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NAME

cunm22.f  

SYNOPSIS


 

Functions/Subroutines


subroutine cunm22 (SIDE, TRANS, M, N, N1, N2, Q, LDQ, C, LDC, WORK, LWORK, INFO)
CUNM22 multiplies a general matrix by a banded unitary matrix.  

Function/Subroutine Documentation

 

subroutine cunm22 (character SIDE, character TRANS, integer M, integer N, integer N1, integer N2, complex, dimension( ldq, * ) Q, integer LDQ, complex, dimension( ldc, * ) C, integer LDC, complex, dimension( * ) WORK, integer LWORK, integer INFO)

CUNM22 multiplies a general matrix by a banded unitary matrix.

Purpose

  CUNM22 overwrites the general complex M-by-N matrix C with

                  SIDE = 'L'     SIDE = 'R'
  TRANS = 'N':      Q * C          C * Q
  TRANS = 'C':      Q**H * C       C * Q**H

  where Q is a complex unitary matrix of order NQ, with NQ = M if
  SIDE = 'L' and NQ = N if SIDE = 'R'.
  The unitary matrix Q processes a 2-by-2 block structure

         [  Q11  Q12  ]
     Q = [            ]
         [  Q21  Q22  ],

  where Q12 is an N1-by-N1 lower triangular matrix and Q21 is an
  N2-by-N2 upper triangular matrix.


 

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.


N1
N2

          N1 is INTEGER
          N2 is INTEGER
          The dimension of Q12 and Q21, respectively. N1, N2 >= 0.
          The following requirement must be satisfied:
          N1 + N2 = M if SIDE = 'L' and N1 + N2 = N if SIDE = 'R'.


Q

          Q is COMPLEX array, dimension
                              (LDQ,M) if SIDE = 'L'
                              (LDQ,N) if SIDE = 'R'


LDQ

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


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 (MAX(1,LWORK))
          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.


LWORK

          LWORK is 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 >= M*N.

          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

          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:

January 2015

Definition at line 164 of file cunm22.f.  

Author

Generated automatically by Doxygen for LAPACK from the source code.


 

Index

NAME
SYNOPSIS
Functions/Subroutines
Function/Subroutine Documentation
subroutine cunm22 (character SIDE, character TRANS, integer M, integer N, integer N1, integer N2, complex, dimension( ldq, * ) Q, integer LDQ, complex, dimension( ldc, * ) C, integer LDC, complex, dimension( * ) WORK, integer LWORK, integer INFO)
Author
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