## 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).

```
```  None
```
Example

Program Text

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Program Data
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Program Results
```  None
```