CLATSY
Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
November 2006
November 2006
Purpose
CLATSY generates a special test matrix for the complex symmetric
(indefinite) factorization. The pivot blocks of the generated matrix
will be in the following order:
2x2 pivot block, non diagonalizable
1x1 pivot block
2x2 pivot block, diagonalizable
(cycle repeats)
A row interchange is required for each non-diagonalizable 2x2 block.
(indefinite) factorization. The pivot blocks of the generated matrix
will be in the following order:
2x2 pivot block, non diagonalizable
1x1 pivot block
2x2 pivot block, diagonalizable
(cycle repeats)
A row interchange is required for each non-diagonalizable 2x2 block.
Arguments
| UPLO |
(input) CHARACTER
Specifies whether the generated matrix is to be upper or
lower triangular. = 'U': Upper triangular = 'L': Lower triangular |
| N |
(input) INTEGER
The dimension of the matrix to be generated.
|
| X |
(output) COMPLEX array, dimension (LDX,N)
The generated matrix, consisting of 3x3 and 2x2 diagonal
blocks which result in the pivot sequence given above. The matrix outside of these diagonal blocks is zero. |
| LDX |
(input) INTEGER
The leading dimension of the array X.
|
| ISEED |
(input/output) INTEGER array, dimension (4)
On entry, the seed for the random number generator. The last
of the four integers must be odd. (modified on exit) |