## AG08BD

### Zeros and Kronecker structure of a descriptor system pencil

[Specification] [Arguments] [Method] [References] [Comments] [Example]

Purpose

      To extract from the system pencil

                        ( A-lambda*E B )
            S(lambda) = (              )
                        (      C     D )

      a regular pencil Af-lambda*Ef which has the finite Smith zeros of
      S(lambda) as generalized eigenvalues. The routine also computes
      the orders of the infinite Smith zeros and determines the singular
      and infinite Kronecker structure of system pencil, i.e., the right
      and left Kronecker indices, and the multiplicities of infinite
      eigenvalues.

Specification

          SUBROUTINE AG08BD( EQUIL, L, N, M, P, A, LDA, E, LDE, B, LDB,
         $                   C, LDC, D, LDD, NFZ, NRANK, NIZ, DINFZ, NKROR,
         $                   NINFE, NKROL, INFZ, KRONR, INFE, KRONL,
         $                   TOL, IWORK, DWORK, LDWORK, INFO )
    C     .. Scalar Arguments ..
          CHARACTER         EQUIL
          INTEGER           DINFZ, INFO, L, LDA, LDB, LDC, LDD, LDE, LDWORK,
         $                  M, N, NFZ, NINFE, NIZ, NKROL, NKROR, NRANK, P
          DOUBLE PRECISION  TOL
    C     .. Array Arguments ..
          INTEGER           INFE(*), INFZ(*), IWORK(*), KRONL(*), KRONR(*)
          DOUBLE PRECISION  A(LDA,*), B(LDB,*), C(LDC,*), D(LDD,*),
         $                  DWORK(*), E(LDE,*)

Arguments

Mode Parameters

      EQUIL   CHARACTER*1
              Specifies whether the user wishes to balance the system
              matrix as follows:
              = 'S':  Perform balancing (scaling);
              = 'N':  Do not perform balancing.

Input/Output Parameters

      L       (input) INTEGER
              The number of rows of matrices A, B, and E.  L >= 0.

      N       (input) INTEGER
              The number of columns of matrices A, E, and C.  N >= 0.

      M       (input) INTEGER
              The number of columns of matrix B.  M >= 0.

      P       (input) INTEGER
              The number of rows of matrix C.  P >= 0.

      A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
              On entry, the leading L-by-N part of this array must
              contain the state dynamics matrix A of the system.
              On exit, the leading NFZ-by-NFZ part of this array
              contains the matrix Af of the reduced pencil.

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

      E       (input/output) DOUBLE PRECISION array, dimension (LDE,N)
              On entry, the leading L-by-N part of this array must
              contain the descriptor matrix E of the system.
              On exit, the leading NFZ-by-NFZ part of this array
              contains the matrix Ef of the reduced pencil.

      LDE     INTEGER
              The leading dimension of array E.  LDE >= MAX(1,L).

      B       (input/output) DOUBLE PRECISION array, dimension (LDB,M)
              On entry, the leading L-by-M part of this array must
              contain the input/state matrix B of the system.
              On exit, this matrix does not contain useful information.

      LDB     INTEGER
              The leading dimension of array B.
              LDB >= MAX(1,L) 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 state/output matrix C of the system.
              On exit, this matrix does not contain useful information.

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

      D       (input) DOUBLE PRECISION array, dimension (LDD,M)
              The leading P-by-M part of this array must contain the
              direct transmission matrix D of the system.

      LDD     INTEGER
              The leading dimension of array D.  LDD >= MAX(1,P).

      NFZ     (output) INTEGER
              The number of finite zeros.

      NRANK   (output) INTEGER
              The normal rank of the system pencil.

      NIZ     (output) INTEGER
              The number of infinite zeros.

      DINFZ   (output) INTEGER
              The maximal multiplicity of infinite Smith zeros.

      NKROR   (output) INTEGER
              The number of right Kronecker indices.

      NINFE   (output) INTEGER
              The number of elementary infinite blocks.

      NKROL   (output) INTEGER
              The number of left Kronecker indices.

      INFZ    (output) INTEGER array, dimension (N+1)
              The leading DINFZ elements of INFZ contain information
              on the infinite elementary divisors as follows:
              the system has INFZ(i) infinite elementary divisors of
              degree i in the Smith form, where i = 1,2,...,DINFZ.

      KRONR   (output) INTEGER array, dimension (N+M+1)
              The leading NKROR elements of this array contain the
              right Kronecker (column) indices.

      INFE    (output) INTEGER array, dimension (1+MIN(L+P,N+M))
              The leading NINFE elements of INFE contain the
              multiplicities of infinite eigenvalues.

      KRONL   (output) INTEGER array, dimension (L+P+1)
              The leading NKROL elements of this array contain the
              left Kronecker (row) indices.

Tolerances

      TOL     DOUBLE PRECISION
              A tolerance used in rank decisions to determine the
              effective rank, which is defined as the order of the
              largest leading (or trailing) triangular submatrix in the
              QR (or RQ) factorization with column (or row) pivoting
              whose estimated condition number is less than 1/TOL.
              If the user sets TOL <= 0, then default tolerances are
              used instead, as follows: TOLDEF = L*N*EPS in TG01FD
              (to determine the rank of E) and TOLDEF = (L+P)*(N+M)*EPS
              in the rest, where EPS is the machine precision
              (see LAPACK Library routine DLAMCH).  TOL < 1.

Workspace

      IWORK   INTEGER array, dimension (N+max(1,M))
              On output, IWORK(1) contains the normal rank of the
              transfer function matrix.

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

      LDWORK  INTEGER
              The length of the array DWORK.
              LDWORK >= max( 4*(L+N), LDW ), if EQUIL = 'S',
              LDWORK >= LDW,                 if EQUIL = 'N', where
              LDW = max(L+P,M+N)*(M+N) + max(1,5*max(L+P,M+N)).
              For optimum performance LDWORK should be larger.

              If LDWORK = -1, then a workspace query is assumed;
              the routine only calculates the optimal size of the
              DWORK array, returns this value as the first entry of
              the DWORK array, and no error message related to LDWORK
              is issued by XERBLA.

Error Indicator

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

Method

      The routine extracts from the system matrix of a descriptor
      system (A-lambda*E,B,C,D) a regular pencil Af-lambda*Ef which
      has the finite zeros of the system as generalized eigenvalues.
      The procedure has the following main computational steps:

         (a) construct the (L+P)-by-(N+M) system pencil

              S(lambda) = ( B  A )-lambda*( 0  E );
                          ( D  C )        ( 0  0 )

         (b) reduce S(lambda) to S1(lambda) with the same finite
             zeros and right Kronecker structure but with E
             upper triangular and nonsingular;

         (c) reduce S1(lambda) to S2(lambda) with the same finite
             zeros and right Kronecker structure but with D of
             full row rank;

         (d) reduce S2(lambda) to S3(lambda) with the same finite zeros
             and with D square invertible;

         (e) perform a unitary transformation on the columns of

             S3(lambda) = (A-lambda*E   B) in order to reduce it to
                          (     C       D)

             (Af-lambda*Ef   X), with Y and Ef square invertible;
             (     0         Y)

         (f) compute the right and left Kronecker indices of the system
             matrix, which together with the multiplicities of the
             finite and infinite eigenvalues constitute the
             complete set of structural invariants under strict
             equivalence transformations of a linear system.

References

      [1] P. Misra, P. Van Dooren and A. Varga.
          Computation of structural invariants of generalized
          state-space systems.
          Automatica, 30, pp. 1921-1936, 1994.

Numerical Aspects

      The algorithm is backward stable (see [1]).

Further Comments

      In order to compute the finite Smith zeros of the system
      explicitly, a call to this routine may be followed by a
      call to the LAPACK Library routines DGEGV or DGGEV.

Example

Program Text

    *     AG08BD EXAMPLE PROGRAM TEXT
    *
    *     .. Parameters ..
          DOUBLE PRECISION ZERO
          PARAMETER        ( ZERO = 0.0D0 )
          INTEGER          NIN, NOUT
          PARAMETER        ( NIN = 5, NOUT = 6 )
          INTEGER          LMAX, MMAX, NMAX, PMAX
          PARAMETER        ( LMAX = 20, MMAX = 20, NMAX = 20, PMAX = 20 )
          INTEGER          LDA, LDAEMX, LDB, LDC, LDD, LDE, LDQ, LDZ
          PARAMETER        ( LDA = LMAX, LDB = LMAX, LDC = PMAX,
         $                   LDD = PMAX, LDE = LMAX, LDQ = 1, LDZ = 1,
         $                   LDAEMX = MAX( PMAX + LMAX, NMAX + MMAX ) )
          INTEGER          LDWORK
          PARAMETER        ( LDWORK = MAX( 4*( LMAX + NMAX ),  8*NMAX,
         $                                 LDAEMX*LDAEMX +
         $                                 MAX( 1, 5*LDAEMX ) ) )
    *     .. Local Scalars ..
          DOUBLE PRECISION TOL
          INTEGER          DINFZ, I, INFO, J, L, M, N, NFZ, NINFE, NIZ,
         $                 NKROL, NKROR, NRANK, P
          CHARACTER*1      EQUIL
    *     .. Local Arrays ..
          DOUBLE PRECISION A(LDA,NMAX), ALFI(NMAX), ALFR(NMAX),
         $                 ASAVE(LDA,NMAX), B(LDB,MMAX), BETA(NMAX),
         $                 BSAVE(LDB,MMAX), C(LDC,NMAX), CSAVE(LDC,NMAX),
         $                 D(LDD,MMAX), DSAVE(LDD,MMAX), DWORK(LDWORK),
         $                 E(LDE,NMAX), ESAVE(LDE,NMAX), Q(LDQ,1), Z(LDZ,1)
          INTEGER          INFE(1+LMAX+PMAX), INFZ(NMAX+1),
         $                 IWORK(NMAX+MMAX), KRONL(LMAX+PMAX+1),
         $                 KRONR(NMAX+MMAX+1)
    *     .. External Subroutines ..
          EXTERNAL         AG08BD, DGEGV, DLACPY
    *     .. Intrinsic Functions ..
          INTRINSIC        MAX
    *     .. Executable Statements ..
    *
          WRITE ( NOUT, FMT = 99999 )
    *     Skip the heading in the data file and read the data.
          READ ( NIN, FMT = '()' )
          READ ( NIN, FMT = * ) L, N, M, P, TOL, EQUIL
          IF( ( L.LT.0 .OR. L.GT.LMAX ) .OR. ( N.LT.0 .OR. N.GT.NMAX ) )
         $   THEN
             WRITE ( NOUT, FMT = 99972 ) L, N
          ELSE
             IF( M.LT.0 .OR. M.GT.MMAX ) THEN
                WRITE ( NOUT, FMT = 99971 ) M
             ELSE
                IF( P.LT.0 .OR. P.GT.PMAX ) THEN
                   WRITE ( NOUT, FMT = 99970 ) P
                ELSE
                   READ ( NIN, FMT = * ) ( ( A(I,J), J = 1,N ), I = 1,L )
                   READ ( NIN, FMT = * ) ( ( E(I,J), J = 1,N ), I = 1,L )
                   READ ( NIN, FMT = * ) ( ( B(I,J), J = 1,M ), I = 1,L )
                   READ ( NIN, FMT = * ) ( ( C(I,J), J = 1,N ), I = 1,P )
                   READ ( NIN, FMT = * ) ( ( D(I,J), J = 1,M ), I = 1,P )
                   CALL DLACPY( 'F', L, N, A, LDA, ASAVE, LDA )
                   CALL DLACPY( 'F', L, N, E, LDE, ESAVE, LDE )
                   CALL DLACPY( 'F', L, M, B, LDB, BSAVE, LDB )
                   CALL DLACPY( 'F', P, N, C, LDC, CSAVE, LDC )
                   CALL DLACPY( 'F', P, M, D, LDD, DSAVE, LDD )
    *              Compute poles (call the routine with M = 0, P = 0).
                   CALL AG08BD( EQUIL, L, N, 0, 0, A, LDA, E, LDE, B, LDB,
         $                      C, LDC, D, LDD, NFZ, NRANK, NIZ, DINFZ,
         $                      NKROR, NINFE, NKROL, INFZ, KRONR, INFE,
         $                      KRONL, TOL, IWORK, DWORK, LDWORK, INFO )
    *
                   IF( INFO.NE.0 ) THEN
                      WRITE ( NOUT, FMT = 99998 ) INFO
                   ELSE
                      WRITE ( NOUT, FMT = 99968 ) NIZ
                      DO 10 I = 1, DINFZ
                         WRITE ( NOUT, FMT = 99967 ) INFZ(I), I
       10             CONTINUE
                      WRITE ( NOUT, FMT = 99962 ) NINFE
                      IF( NINFE.GT.0 ) WRITE ( NOUT, FMT = 99958 )
         $                                      ( INFE(I), I = 1,NINFE )
                      IF( NFZ.EQ.0 ) THEN
                         WRITE ( NOUT, FMT = 99965 )
                      ELSE
                         WRITE ( NOUT, FMT = 99966 )
                         WRITE ( NOUT, FMT = 99990 )
                         DO 20 I = 1, NFZ
                            WRITE ( NOUT, FMT = 99989 )
         $                        ( A(I,J), J = 1,NFZ )
       20                CONTINUE
                         WRITE ( NOUT, FMT = 99995 )
                         DO 30 I = 1, NFZ
                            WRITE ( NOUT, FMT = 99989 )
         $                        ( E(I,J), J = 1,NFZ )
       30                CONTINUE
                         CALL DGEGV( 'No vectors', 'No vectors', NFZ, A,
         $                           LDA, E, LDE, ALFR, ALFI, BETA, Q,
         $                           LDQ, Z, LDZ, DWORK, LDWORK, INFO )
    *
                         IF( INFO.NE.0 ) THEN
                            WRITE ( NOUT, FMT = 99997 ) INFO
                         ELSE
                            WRITE ( NOUT, FMT = 99996 )
                            DO 40 I = 1, NFZ
                               IF( ALFI(I).EQ.ZERO ) THEN
                                  WRITE ( NOUT, FMT = 99980 )
         $                                ALFR(I)/BETA(I)
                               ELSE
                                  WRITE ( NOUT, FMT = 99979 )
         $                                ALFR(I)/BETA(I),
         $                                ALFI(I)/BETA(I)
                               END IF
       40                   CONTINUE
                         END IF
                      END IF
                   END IF
                   CALL DLACPY( 'F', L, N, ASAVE, LDA, A, LDA )
                   CALL DLACPY( 'F', L, N, ESAVE, LDE, E, LDE )
    *              Check the observability and compute the ordered set of
    *              the observability indices (call the routine with M = 0).
                   CALL AG08BD( EQUIL, L, N, 0, P, A, LDA, E, LDE, B, LDB,
         $                      C, LDC, D, LDD, NFZ, NRANK, NIZ, DINFZ,
         $                      NKROR, NINFE, NKROL, INFZ, KRONR, INFE,
         $                      KRONL, TOL, IWORK, DWORK, LDWORK, INFO )
    *
                   IF( INFO.NE.0 ) THEN
                      WRITE ( NOUT, FMT = 99998 ) INFO
                   ELSE
                      WRITE ( NOUT, FMT = 99964 ) NIZ
                      DO 50 I = 1, DINFZ
                         WRITE ( NOUT, FMT = 99967 ) INFZ(I), I
       50             CONTINUE
                      WRITE ( NOUT, FMT = 99962 ) NINFE
                      IF( NINFE.GT.0 ) WRITE ( NOUT, FMT = 99960 )
         $                                     ( INFE(I), I = 1,NINFE )
                      WRITE ( NOUT, FMT = 99994 ) ( KRONL(I), I = 1,NKROL )
                      IF( NFZ+NINFE.EQ.0 ) WRITE ( NOUT, FMT = 99993 )
                      IF( NFZ.EQ.0 ) THEN
                         WRITE ( NOUT, FMT = 99957 )
                      ELSE
                         WRITE ( NOUT, FMT = 99991 )
                         WRITE ( NOUT, FMT = 99990 )
                         DO 60 I = 1, NFZ
                            WRITE ( NOUT, FMT = 99989 )
         $                        ( A(I,J), J = 1,NFZ )
       60                CONTINUE
                         WRITE ( NOUT, FMT = 99995 )
                         DO 70 I = 1, NFZ
                            WRITE ( NOUT, FMT = 99989 )
         $                        ( E(I,J), J = 1,NFZ )
       70                CONTINUE
                         CALL DGEGV( 'No vectors', 'No vectors', NFZ, A,
         $                           LDA, E, LDE, ALFR, ALFI, BETA, Q,
         $                           LDQ, Z, LDZ, DWORK, LDWORK, INFO )
    *
                         IF( INFO.NE.0 ) THEN
                            WRITE ( NOUT, FMT = 99997 ) INFO
                         ELSE
                            WRITE ( NOUT, FMT = 99996 )
                            DO 80 I = 1, NFZ
                               IF( ALFI(I).EQ.ZERO ) THEN
                                  WRITE ( NOUT, FMT = 99980 )
         $                                ALFR(I)/BETA(I)
                               ELSE
                                  WRITE ( NOUT, FMT = 99979 )
         $                                ALFR(I)/BETA(I),
         $                                ALFI(I)/BETA(I)
                               END IF
       80                   CONTINUE
                         END IF
                      END IF
                   END IF
                   CALL DLACPY( 'F', L, N, ASAVE, LDA, A, LDA )
                   CALL DLACPY( 'F', L, N, ESAVE, LDE, E, LDE )
                   CALL DLACPY( 'F', P, N, CSAVE, LDC, C, LDC )
    *              Check the controllability and compute the ordered set of
    *              the controllability indices (call the routine with P = 0)
                   CALL AG08BD( EQUIL, L, N, M, 0, A, LDA, E, LDE, B, LDB,
         $                      C, LDC, D, LDD, NFZ, NRANK, NIZ, DINFZ,
         $                      NKROR, NINFE, NKROL, INFZ, KRONR, INFE,
         $                      KRONL, TOL, IWORK, DWORK, LDWORK, INFO )
    *
                   IF( INFO.NE.0 ) THEN
                      WRITE ( NOUT, FMT = 99998 ) INFO
                   ELSE
                      WRITE ( NOUT, FMT = 99963 ) NIZ
                      DO 90  I = 1, DINFZ
                         WRITE ( NOUT, FMT = 99967 ) INFZ(I), I
       90             CONTINUE
                      WRITE ( NOUT, FMT = 99962 ) NINFE
                      IF( NINFE.GT.0 ) WRITE ( NOUT, FMT = 99959 )
         $                                     ( INFE(I), I = 1,NINFE )
                      WRITE ( NOUT, FMT = 99988 ) ( KRONR(I), I = 1,NKROR )
                      IF( NFZ+NINFE.EQ.0 ) WRITE ( NOUT, FMT = 99987 )
                      IF( NFZ.EQ.0 ) THEN
                         WRITE ( NOUT, FMT = 99956 )
                      ELSE
                         WRITE ( NOUT, FMT = 99985 )
                         WRITE ( NOUT, FMT = 99990 )
                         DO 100 I = 1, NFZ
                            WRITE ( NOUT, FMT = 99989 )
         $                        ( A(I,J), J = 1,NFZ )
      100                CONTINUE
                         WRITE ( NOUT, FMT = 99995 )
                         DO 110 I = 1, NFZ
                            WRITE ( NOUT, FMT = 99989 )
         $                        ( E(I,J), J = 1,NFZ )
      110                CONTINUE
                         CALL DGEGV( 'No vectors', 'No vectors', NFZ, A,
         $                           LDA, E, LDE, ALFR, ALFI, BETA, Q,
         $                           LDQ, Z, LDZ, DWORK, LDWORK, INFO )
    *
                         IF( INFO.NE.0 ) THEN
                            WRITE ( NOUT, FMT = 99997 ) INFO
                         ELSE
                            WRITE ( NOUT, FMT = 99982 )
                            DO 120 I = 1, NFZ
                               IF( ALFI(I).EQ.ZERO ) THEN
                                  WRITE ( NOUT, FMT = 99980 )
         $                                ALFR(I)/BETA(I)
                               ELSE
                                  WRITE ( NOUT, FMT = 99979 )
         $                                ALFR(I)/BETA(I),
         $                                ALFI(I)/BETA(I)
                               END IF
      120                   CONTINUE
                         END IF
                      END IF
                   END IF
                   CALL DLACPY( 'F', L, N, ASAVE, LDA, A, LDA )
                   CALL DLACPY( 'F', L, N, ESAVE, LDE, E, LDE )
                   CALL DLACPY( 'F', L, M, BSAVE, LDB, B, LDB )
                   CALL DLACPY( 'F', P, N, CSAVE, LDC, C, LDC )
                   CALL DLACPY( 'F', P, M, DSAVE, LDD, D, LDD )
    *              Compute the structural invariants of the given system.
                   CALL AG08BD( EQUIL, L, N, M, P, A, LDA, E, LDE, B, LDB,
         $                      C, LDC, D, LDD, NFZ, NRANK, NIZ, DINFZ,
         $                      NKROR, NINFE, NKROL, INFZ, KRONR, INFE,
         $                      KRONL, TOL, IWORK, DWORK, LDWORK, INFO )
    *
                   IF( INFO.NE.0 ) THEN
                      WRITE ( NOUT, FMT = 99998 ) INFO
                   ELSE
                      IF( L.EQ.N ) THEN
                         WRITE ( NOUT, FMT = 99969 ) NRANK - N
                      ELSE
                         WRITE ( NOUT, FMT = 99955 ) NRANK
                      END IF
                      WRITE ( NOUT, FMT = 99984 ) NFZ
                      IF( NFZ.GT.0 ) THEN
    *                    Compute the finite zeros of the given system.
    *                    Workspace: need 8*NFZ.
                         WRITE ( NOUT, FMT = 99983 )
                         WRITE ( NOUT, FMT = 99990 )
                         DO 130 I = 1, NFZ
                            WRITE ( NOUT, FMT = 99989 )
         $                        ( A(I,J), J = 1,NFZ )
      130                CONTINUE
                         WRITE ( NOUT, FMT = 99995 )
                         DO 140 I = 1, NFZ
                            WRITE ( NOUT, FMT = 99989 )
         $                        ( E(I,J), J = 1,NFZ )
      140                CONTINUE
                         CALL DGEGV( 'No vectors', 'No vectors', NFZ, A,
         $                           LDA, E, LDE, ALFR, ALFI, BETA, Q,
         $                           LDQ, Z, LDZ, DWORK, LDWORK, INFO )
    *
                         IF( INFO.NE.0 ) THEN
                            WRITE ( NOUT, FMT = 99997 ) INFO
                         ELSE
                            WRITE ( NOUT, FMT = 99981 )
                            DO 150 I = 1, NFZ
                               IF( ALFI(I).EQ.ZERO ) THEN
                                  WRITE ( NOUT, FMT = 99980 )
         $                                ALFR(I)/BETA(I)
                               ELSE
                                  WRITE ( NOUT, FMT = 99979 )
         $                                ALFR(I)/BETA(I),
         $                                ALFI(I)/BETA(I)
                               END IF
      150                   CONTINUE
                         END IF
                      END IF
                      WRITE ( NOUT, FMT = 99978 ) NIZ
                      DO 160 I = 1, DINFZ
                         WRITE ( NOUT, FMT = 99977 ) INFZ(I), I
      160             CONTINUE
                      WRITE ( NOUT, FMT = 99962 ) NINFE
                      IF( NINFE.GT.0 ) WRITE ( NOUT, FMT = 99961 )
         $                                     ( INFE(I), I = 1,NINFE )
                      WRITE ( NOUT, FMT = 99976 ) NKROR
                      IF( NKROR.GT.0 ) WRITE ( NOUT, FMT = 99975 )
         $                                     ( KRONR(I), I = 1,NKROR )
                      WRITE ( NOUT, FMT = 99974 ) NKROL
                      IF( NKROL.GT.0 ) WRITE ( NOUT, FMT = 99973 )
         $                                     ( KRONL(I), I = 1,NKROL )
                   END IF
                END IF
             END IF
          END IF
    *
          STOP
    *
    99999 FORMAT (' AG08BD EXAMPLE PROGRAM RESULTS',/1X)
    99998 FORMAT (' INFO on exit from AG08BD = ',I2)
    99997 FORMAT (' INFO on exit from DGEGV = ',I2)
    99996 FORMAT (/'Unobservable finite eigenvalues'/
         $         ' real  part     imag  part ')
    99995 FORMAT (/' The matrix Ef is ')
    99994 FORMAT (/' The left Kronecker indices of [A-lambda*E;C] are ',
         $          /(20(I3,2X)))
    99993 FORMAT (/' The system (A-lambda*E,C) is completely observable ')
    99991 FORMAT (/' The finite output decoupling zeros are the eigenvalues'
         $       ,' of the pair (Af,Ef). ')
    99990 FORMAT (/' The matrix Af is ')
    99989 FORMAT (20(1X,F8.4))
    99988 FORMAT (/' The right Kronecker indices of [A-lambda*E,B] are ',
         $        /( 20(I3,2X) ) )
    99987 FORMAT (/' The system (A-lambda*E,B) is completely controllable ')
    99985 FORMAT (/' The input decoupling zeros are the eigenvalues of the',
         $       ' pair (Af,Ef). ')
    99984 FORMAT (/' The number of finite zeros = ',I3)
    99983 FORMAT (/' The finite zeros are the eigenvalues ',
         $         'of the pair (Af,Ef)')
    99982 FORMAT (/'Uncontrollable finite eigenvalues'/
         $         ' real  part     imag  part ')
    99981 FORMAT (/'Finite zeros'/' real  part     imag  part ')
    99980 FORMAT (1X,F9.4)
    99979 FORMAT (1X,F9.4,6X,F9.4)
    99978 FORMAT (//' The number of infinite zeros = ',I3)
    99977 FORMAT ( I4,' infinite zero(s) of order ',I3)
    99976 FORMAT (/' The number of right Kronecker indices = ',I3)
    99975 FORMAT (/' Right Kronecker indices of [A-lambda*E,B;C,D]'
         $         ,' are ', /(20(I3,2X)))
    99974 FORMAT (/' The number of left Kronecker indices = ',I3)
    99973 FORMAT (/' The left Kronecker indices of [A-lambda*E,B;C,D]'
         $         ,' are ',  /(20(I3,2X)))
    99972 FORMAT (/' L or N is out of range.',/' L = ', I5, '  N = ',I5)
    99971 FORMAT (/' M is out of range.',/' M = ',I5)
    99970 FORMAT (/' P is out of range.',/' P = ',I5)
    99969 FORMAT (/' Normal rank  of transfer function matrix = ',I3)
    99968 FORMAT (//' The number of infinite poles = ',I3)
    99967 FORMAT ( I4,' infinite pole(s) of order ',I3)
    99966 FORMAT (/' The finite poles are the eigenvalues',
         $       ' of the pair (Af,Ef). ')
    99965 FORMAT (/' The system has no finite poles ')
    99964 FORMAT (//' The number of unobservable infinite poles = ',I3)
    99963 FORMAT (//' The number of uncontrollable infinite poles = ',I3)
    99962 FORMAT (/' The number of infinite Kronecker blocks = ',I3)
    99961 FORMAT (/' Multiplicities of infinite eigenvalues of '
         $         ,'[A-lambda*E,B;C,D] are ', /(20(I3,2X)))
    99960 FORMAT (/' Multiplicities of infinite eigenvalues of '
         $         ,'[A-lambda*E;C] are ', /(20(I3,2X)))
    99959 FORMAT (/' Multiplicities of infinite eigenvalues of '
         $         ,'[A-lambda*E,B] are ', /(20(I3,2X)))
    99958 FORMAT (/' Multiplicities of infinite eigenvalues of A-lambda*E'
         $         ,' are ', /(20(I3,2X)))
    99957 FORMAT (/' The system (A-lambda*E,C) has no finite output',
         $         ' decoupling zeros ')
    99956 FORMAT (/' The system (A-lambda*E,B) has no finite input',
         $         ' decoupling zeros ')
    99955 FORMAT (/' Normal rank  of system pencil = ',I3)
          END

Program Data

     AG08BD EXAMPLE PROGRAM DATA
       9    9    3     3     1.e-7     N
         1     0     0     0     0     0     0     0     0
         0     1     0     0     0     0     0     0     0
         0     0     1     0     0     0     0     0     0
         0     0     0     1     0     0     0     0     0
         0     0     0     0     1     0     0     0     0
         0     0     0     0     0     1     0     0     0
         0     0     0     0     0     0     1     0     0
         0     0     0     0     0     0     0     1     0
         0     0     0     0     0     0     0     0     1
         0     0     0     0     0     0     0     0     0
         1     0     0     0     0     0     0     0     0
         0     1     0     0     0     0     0     0     0
         0     0     0     0     0     0     0     0     0
         0     0     0     1     0     0     0     0     0
         0     0     0     0     1     0     0     0     0
         0     0     0     0     0     0     0     0     0
         0     0     0     0     0     0     1     0     0
         0     0     0     0     0     0     0     1     0
        -1     0     0
         0     0     0
         0     0     0
         0    -1     0
         0     0     0
         0     0     0
         0     0    -1
         0     0     0
         0     0     0
         0     1     1     0     3     4     0     0     2
         0     1     0     0     4     0     0     2     0
         0     0     1     0    -1     4     0    -2     2
         1     2    -2
         0    -1    -2
         0     0     0

Program Results

     AG08BD EXAMPLE PROGRAM RESULTS

     The number of infinite poles =   6
       0 infinite pole(s) of order   1
       3 infinite pole(s) of order   2

     The number of infinite Kronecker blocks =   3

     Multiplicities of infinite eigenvalues of A-lambda*E are
      3    3    3

     The system has no finite poles

     The number of unobservable infinite poles =   4
       0 infinite pole(s) of order   1
       2 infinite pole(s) of order   2

     The number of infinite Kronecker blocks =   3

     Multiplicities of infinite eigenvalues of [A-lambda*E;C] are
      1    3    3

     The left Kronecker indices of [A-lambda*E;C] are
      0    1    1

     The system (A-lambda*E,C) has no finite output decoupling zeros

     The number of uncontrollable infinite poles =   0

     The number of infinite Kronecker blocks =   3

     Multiplicities of infinite eigenvalues of [A-lambda*E,B] are
      1    1    1

     The right Kronecker indices of [A-lambda*E,B] are
      2    2    2

     The system (A-lambda*E,B) has no finite input decoupling zeros

     Normal rank  of transfer function matrix =   2

     The number of finite zeros =   1

     The finite zeros are the eigenvalues of the pair (Af,Ef)

     The matrix Af is
       0.7705

     The matrix Ef is
       0.7705

    Finite zeros
     real  part     imag  part
        1.0000

     The number of infinite zeros =   2
       0 infinite zero(s) of order   1
       1 infinite zero(s) of order   2

     The number of infinite Kronecker blocks =   5

     Multiplicities of infinite eigenvalues of [A-lambda*E,B;C,D] are
      1    1    1    1    3

     The number of right Kronecker indices =   1

     Right Kronecker indices of [A-lambda*E,B;C,D] are
      2

     The number of left Kronecker indices =   1

     The left Kronecker indices of [A-lambda*E,B;C,D] are
      1

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