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.TH DPOTRF l "15 June 2000" "LAPACK version 3.0" ")"
.SH NAME
DPOTRF - compute the Cholesky factorization of a real symmetric positive definite matrix A
.SH SYNOPSIS
.TP 19
SUBROUTINE DPOTRF(
UPLO, N, A, LDA, INFO )
.TP 19
.ti +4
CHARACTER
UPLO
.TP 19
.ti +4
INTEGER
INFO, LDA, N
.TP 19
.ti +4
DOUBLE
PRECISION A( LDA, * )
.SH PURPOSE
DPOTRF computes the Cholesky factorization of a real symmetric positive definite matrix A.
The factorization has the form
.br
A = U**T * U, if UPLO = 'U', or
.br
A = L * L**T, if UPLO = 'L',
.br
where U is an upper triangular matrix and L is lower triangular.
This is the block version of the algorithm, calling Level 3 BLAS.
.SH ARGUMENTS
.TP 8
UPLO (input) CHARACTER*1
= 'U': Upper triangle of A is stored;
.br
= 'L': Lower triangle of A is stored.
.TP 8
N (input) INTEGER
The order of the matrix A. N >= 0.
.TP 8
A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
On entry, the symmetric matrix A. If UPLO = 'U', the leading
N-by-N upper triangular part of A contains the upper
triangular 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.
.TP 8
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1,N).
.TP 8
INFO (output) INTEGER
= 0: successful exit
.br
< 0: if INFO = -i, the i-th argument had an illegal value
.br
> 0: if INFO = i, the leading minor of order i is not
positive definite, and the factorization could not be
completed.
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