dpotrf(3P) Sun Performance Library dpotrf(3P)NAMEdpotrf - compute the Cholesky factorization of a real symmetric posi‐
tive definite matrix A
SYNOPSIS
SUBROUTINE DPOTRF(UPLO, N, A, LDA, INFO)
CHARACTER * 1 UPLO
INTEGER N, LDA, INFO
DOUBLE PRECISION A(LDA,*)
SUBROUTINE DPOTRF_64(UPLO, N, A, LDA, INFO)
CHARACTER * 1 UPLO
INTEGER*8 N, LDA, INFO
DOUBLE PRECISION A(LDA,*)
F95 INTERFACE
SUBROUTINE POTRF(UPLO, [N], A, [LDA], [INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER :: N, LDA, INFO
REAL(8), DIMENSION(:,:) :: A
SUBROUTINE POTRF_64(UPLO, [N], A, [LDA], [INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER(8) :: N, LDA, INFO
REAL(8), DIMENSION(:,:) :: A
C INTERFACE
#include <sunperf.h>
void dpotrf(char uplo, int n, double *a, int lda, int *info);
void dpotrf_64(char uplo, long n, double *a, long lda, long *info);
PURPOSEdpotrf computes the Cholesky factorization of a real symmetric positive
definite matrix A.
The factorization has the form
A = U**T * U, if UPLO = 'U', or
A = L * L**T, if UPLO = 'L',
where U is an upper triangular matrix and L is lower triangular.
This is the block version of the algorithm, calling Level 3 BLAS.
ARGUMENTS
UPLO (input)
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.
N (input) The order of the matrix A. N >= 0.
A (input/output)
On entry, the symmetric matrix A. If UPLO = 'U', the leading
N-by-N upper triangular part of A contains the upper triangu‐
lar part of the matrix A, and the strictly lower triangular
part of A is not referenced. If UPLO = 'L', the leading N-
by-N lower triangular part of A contains the lower triangular
part of the matrix A, and the strictly upper triangular part
of A is not referenced.
On exit, if INFO = 0, the factor U or L from the Cholesky
factorization A = U**T*U or A = L*L**T.
LDA (input)
The leading dimension of the array A. LDA >= max(1,N).
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: if INFO = i, the leading minor of order i is not posi‐
tive definite, and the factorization could not be completed.
6 Mar 2009 dpotrf(3P)
