chptrf
chptrf - compute the factorization of a complex Hermitian packed matrix A using the Bunch-Kaufman diagonal pivoting method
SUBROUTINE CHPTRF( UPLO, N, A, IPIVOT, INFO)
CHARACTER * 1 UPLO
COMPLEX A(*)
INTEGER N, INFO
INTEGER IPIVOT(*)
SUBROUTINE CHPTRF_64( UPLO, N, A, IPIVOT, INFO)
CHARACTER * 1 UPLO
COMPLEX A(*)
INTEGER*8 N, INFO
INTEGER*8 IPIVOT(*)
SUBROUTINE HPTRF( UPLO, [N], A, IPIVOT, [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX, DIMENSION(:) :: A
INTEGER :: N, INFO
INTEGER, DIMENSION(:) :: IPIVOT
SUBROUTINE HPTRF_64( UPLO, [N], A, IPIVOT, [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX, DIMENSION(:) :: A
INTEGER(8) :: N, INFO
INTEGER(8), DIMENSION(:) :: IPIVOT
#include <sunperf.h>
void chptrf(char uplo, int n, complex *a, int *ipivot, int *info);
void chptrf_64(char uplo, long n, complex *a, long *ipivot, long *info);
chptrf computes the factorization of a complex Hermitian packed
matrix A using the Bunch-Kaufman diagonal pivoting method:
A = U*D*U**H or A = L*D*L**H
where U (or L) is a product of permutation and unit upper (lower)
triangular matrices, and D is Hermitian and block diagonal with
1-by-1 and 2-by-2 diagonal blocks.
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* UPLO (input)
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* N (input)
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The order of the matrix A. N >= 0.
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* A (input/output)
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On entry, the upper or lower triangle of the Hermitian 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).
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* IPIVOT (output)
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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.
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* INFO (output)
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