# zlagsy.f - Man Page

TESTING/MATGEN/zlagsy.f

## Synopsis

### Functions/Subroutines

subroutine **zlagsy** (n, k, d, a, lda, iseed, work, info)**ZLAGSY**

## Function/Subroutine Documentation

### subroutine zlagsy (integer n, integer k, double precision, dimension( * ) d, complex*16, dimension( lda, * ) a, integer lda, integer, dimension( 4 ) iseed, complex*16, dimension( * ) work, integer info)

**ZLAGSY**

**Purpose:**

ZLAGSY generates a complex symmetric matrix A, by pre- and post- multiplying a real diagonal matrix D with a random unitary matrix: A = U*D*U**T. The semi-bandwidth may then be reduced to k by additional unitary transformations.

**Parameters***N*N is INTEGER The order of the matrix A. N >= 0.

*K*K is INTEGER The number of nonzero subdiagonals within the band of A. 0 <= K <= N-1.

*D*D is DOUBLE PRECISION array, dimension (N) The diagonal elements of the diagonal matrix D.

*A*A is COMPLEX*16 array, dimension (LDA,N) The generated n by n symmetric matrix A (the full matrix is stored).

*LDA*LDA is INTEGER The leading dimension of the array A. LDA >= N.

*ISEED*ISEED is INTEGER array, dimension (4) On entry, the seed of the random number generator; the array elements must be between 0 and 4095, and ISEED(4) must be odd. On exit, the seed is updated.

*WORK*WORK is COMPLEX*16 array, dimension (2*N)

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

**Author**Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **101** of file **zlagsy.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page zlagsy(3) is an alias of zlagsy.f(3).

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK