zsptrf
zsptrf - compute the factorization of a complex symmetric matrix A stored in packed format using the Bunch-Kaufman diagonal pivoting method
SUBROUTINE ZSPTRF( UPLO, N, A, IPIVOT, INFO)
CHARACTER * 1 UPLO
DOUBLE COMPLEX A(*)
INTEGER N, INFO
INTEGER IPIVOT(*)
SUBROUTINE ZSPTRF_64( UPLO, N, A, IPIVOT, INFO)
CHARACTER * 1 UPLO
DOUBLE COMPLEX A(*)
INTEGER*8 N, INFO
INTEGER*8 IPIVOT(*)
SUBROUTINE SPTRF( UPLO, [N], A, IPIVOT, [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX(8), DIMENSION(:) :: A
INTEGER :: N, INFO
INTEGER, DIMENSION(:) :: IPIVOT
SUBROUTINE SPTRF_64( UPLO, [N], A, IPIVOT, [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX(8), DIMENSION(:) :: A
INTEGER(8) :: N, INFO
INTEGER(8), DIMENSION(:) :: IPIVOT
#include <sunperf.h>
void zsptrf(char uplo, int n, doublecomplex *a, int *ipivot, int *info);
void zsptrf_64(char uplo, long n, doublecomplex *a, long *ipivot, long *info);
zsptrf computes the factorization of a complex symmetric matrix A
stored in packed format using the Bunch-Kaufman diagonal pivoting
method:
A = U*D*U**T or A = L*D*L**T
where U (or L) is a product of permutation and unit upper (lower)
triangular matrices, and D is symmetric and block diagonal with
1-by-1 and 2-by-2 diagonal blocks.
-
* UPLO (input)
-
-
* N (input)
-
The order of the matrix A. N >= 0.
-
* A (input/output)
-
On entry, the upper or lower triangle of the symmetric matrix
A, packed columnwise in a linear array. The j-th column of A
is stored in the array A as follows:
if UPLO = 'U', A(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
if UPLO = 'L', A(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
On exit, the block diagonal matrix D and the multipliers used
to obtain the factor U or L, stored as a packed triangular
matrix overwriting A (see below for further details).
-
* IPIVOT (output)
-
Details of the interchanges and the block structure of D.
If IPIVOT(k) > 0, then rows and columns k and IPIVOT(k) were
interchanged and D(k,k) is a 1-by-1 diagonal block.
If UPLO = 'U' and IPIVOT(k) = IPIVOT(k-1) < 0, then rows and
columns k-1 and -IPIVOT(k) were interchanged and D(k-1:k,k-1:k)
is a 2-by-2 diagonal block. If UPLO = 'L' and IPIVOT(k) =
IPIVOT(k+1) < 0, then rows and columns k+1 and -IPIVOT(k) were
interchanged and D(k:k+1,k:k+1) is a 2-by-2 diagonal block.
-
* INFO (output)
-