## MA02OZ

### Compute the number of zero rows (and zero columns) of a complex (skew-)Hamiltonian matrix

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

Purpose

      To compute the number of zero rows (and zero columns) of a complex
      (skew-)Hamiltonian matrix,

            (  A    D   )
        H = (           ).
            (  E  +/-A' )

Specification

          INTEGER FUNCTION MA02OZ( SKEW, M, A, LDA, DE, LDDE )
    C     .. Scalar Arguments ..
          CHARACTER          SKEW
          INTEGER            LDA, LDDE, M
    C     .. Array Arguments ..
          COMPLEX*16         A( LDA, * ), DE( LDDE, * )

Function Value

      MA02OZ  INTEGER
              The number of zero rows.

Arguments

Mode Parameters

      SKEW    CHARACTER*1
              Specifies whether the matrix is Hamiltonian or skew-
              Hamiltonian as follows:
              = 'H':  The matrix is Hamiltonian;
              = 'S':  The matrix is skew-Hamiltonian.

Input/Output Parameters

      M       (input) INTEGER
              The order of the matrices A, D, and E.  M >= 0.

      A       (input) COMPLEX*16 array, dimension (LDA,M)
              The leading M-by-M part of this array must contain the
              matrix A.

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

      DE      (input) COMPLEX*16 array, dimension (LDDE,M+1)
              The leading M-by-M lower triangular part of this array
              must contain the lower triangular part of the (skew-)
              Hermitian matrix E, and the M-by-M upper triangular
              part of the submatrix in the columns 2 to M+1 of this
              array must contain the upper triangular part of the
              (skew-)Hermitian matrix D. If S is skew-Hamiltonian, the
              real parts of the entries on the diagonal and the first
              superdiagonal of this array, which should be zero, are
              not used. If S is Hamiltonian, the imaginary parts of the
              entries on the diagonal and the first superdiagonal of
              this array, which should be zero, are not used.

      LDDE    INTEGER
              The leading dimension of the array DE.  LDDE >= MAX(1,M).

Further Comments

      None

Example

Program Text

      None

Program Data

      None

Program Results

      None

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