TB01YD

Special similarity transformation of a state-space system

Purpose

  To apply a special similarity transformation to a system given as
  a triple (A,B,C),

     A <-- P * A * P,  B <-- P * B,  C <-- C * P,

  where P is a matrix with 1 on the secondary diagonal, and with 0
  in the other entries.

      SUBROUTINE TB01YD( N, M, P, A, LDA, B, LDB, C, LDC, INFO )
C     .. Scalar Arguments ..
      INTEGER            INFO, LDA, LDB, LDC, M, N, P
C     .. Array Arguments ..
      DOUBLE PRECISION   A( LDA, * ), B( LDB, * ), C( LDC, * )

Input/Output Parameters

  N       (input) INTEGER
          The order of the matrix A, the number of rows of matrix B
          and the number of columns of matrix C.
          N represents the dimension of the state vector.  N >= 0.

  M       (input) INTEGER.
          The number of columns of matrix B.
          M represents the dimension of input vector.  M >= 0.

  P       (input) INTEGER.
          The number of rows of matrix C.
          P represents the dimension of output vector.  P >= 0.

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

  LDA     INTEGER
          The leading dimension of the array A.  LDA >= MAX(1,N).

  B       (input/output) DOUBLE PRECISION array, dimension (LDB,M)
          On entry, the leading N-by-M part of this array must
          contain the system input matrix B.
          On exit, the leading N-by-M part of this array contains
          the transformed matrix P*B.

  LDB     INTEGER
          The leading dimension of the array B.
          LDB >= MAX(1,N) if M > 0.
          LDB >= 1        if M = 0.

  C       (input/output) DOUBLE PRECISION array, dimension (LDC,N)
          On entry, the leading P-by-N part of this array must
          contain the system output matrix C.
          On exit, the leading P-by-N part of this array contains
          the transformed matrix C*P.

  LDC     INTEGER
          The leading dimension of the array C.  LDC >= MAX(1,P).

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

  The rows and/or columns of the matrices of the triplet (A,B,C)
  are swapped in a special way.

  None.

  None

Program Text

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