MB02CY

Applying the MB02CX transformations on other columns / rows of the generator

Purpose

  To apply the transformations created by the SLICOT Library
  routine MB02CX on other columns / rows of the generator,
  contained in the arrays A and B of positive and negative
  generators, respectively.

      SUBROUTINE MB02CY( TYPET, STRUCG, P, Q, N, K, A, LDA, B, LDB, H,
     $                   LDH, CS, LCS, DWORK, LDWORK, INFO )
C     .. Scalar Arguments ..
      INTEGER           INFO, K, LDA, LDB, LCS, LDH, LDWORK, N, P, Q
      CHARACTER         STRUCG, TYPET
C     .. Array Arguments ..
      DOUBLE PRECISION  A(LDA, *), B(LDB, *), CS(*), DWORK(*), H(LDH,*)

Mode Parameters

  TYPET   CHARACTER*1
          Specifies the type of the generator, as follows:
          = 'R':  A and B are additional columns of the generator;
          = 'C':  A and B are additional rows of the generator.
          Note:   in the sequel, the notation x / y means that
                  x corresponds to TYPET = 'R' and y corresponds to
                  TYPET = 'C'.

  STRUCG  CHARACTER*1
          Information about the structure of the two generators,
          as follows:
          = 'T':  the trailing block of the positive generator
                  is lower / upper triangular, and the trailing
                  block of the negative generator is zero;
          = 'N':  no special structure to mention.

  P       (input)  INTEGER
          The number of rows / columns in A containing the positive
          generators.  P >= 0.

  Q       (input)  INTEGER
          The number of rows / columns in B containing the negative
          generators.  Q >= 0.

  N       (input)  INTEGER
          The number of columns / rows in A and B to be processed.
          N >= 0.

  K       (input)  INTEGER
          The number of columns / rows in H.  P >= K >= 0.

  A       (input/output)  DOUBLE PRECISION array, dimension
          (LDA, N) / (LDA, P)
          On entry, the leading P-by-N / N-by-P part of this array
          must contain the positive part of the generator.
          On exit, the leading P-by-N / N-by-P part of this array
          contains the transformed positive part of the generator.

  LDA     INTEGER
          The leading dimension of the array A.
          LDA >= MAX(1,P),    if TYPET = 'R';
          LDA >= MAX(1,N),    if TYPET = 'C'.

  B       (input/output)  DOUBLE PRECISION array, dimension
          (LDB, N) / (LDB, Q)
          On entry, the leading Q-by-N / N-by-Q part of this array
          must contain the negative part of the generator.
          On exit, the leading Q-by-N / N-by-Q part of this array
          contains the transformed negative part of the generator.

  LDB     INTEGER
          The leading dimension of the array B.
          LDB >= MAX(1,Q),    if TYPET = 'R';
          LDB >= MAX(1,N),    if TYPET = 'C'.

  H       (input)  DOUBLE PRECISION array, dimension
          (LDH, K) / (LDH, Q)
          The leading Q-by-K / K-by-Q part of this array must
          contain part of the necessary information for the
          Householder transformations computed by SLICOT Library
          routine MB02CX.

  LDH     INTEGER
          The leading dimension of the array H.
          LDH >= MAX(1,Q),    if TYPET = 'R';
          LDH >= MAX(1,K),    if TYPET = 'C'.

  CS      (input)  DOUBLE PRECISION array, dimension (LCS)
          The leading 2*K + MIN(K,Q) part of this array must
          contain the necessary information for modified hyperbolic
          rotations and the scalar factors of the Householder
          transformations computed by SLICOT Library routine MB02CX.

  LCS     INTEGER
          The length of the array CS.  LCS >= 2*K + MIN(K,Q).

  DWORK   DOUBLE PRECISION array, dimension (LDWORK)
          On exit, if  INFO = 0,  DWORK(1)  returns the optimal
          value of LDWORK.
          On exit, if  INFO = -16,  DWORK(1)  returns the minimum
          value of LDWORK.

  LDWORK  INTEGER
          The length of the array DWORK.  LDWORK >= MAX(1,N).
          For optimum performance LDWORK should be larger.

  INFO    INTEGER
          = 0:  succesful exit;
          < 0:  if INFO = -i, the i-th argument had an illegal
                value.

  The Householder transformations and modified hyperbolic rotations
  computed by SLICOT Library routine MB02CX are applied to the
  corresponding parts of the matrices A and B.

  None

Program Text

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