# CentOS 7.0 - man page for spotrf (centos section 3)

```spotrf.f(3)							      LAPACK							       spotrf.f(3)

NAME
spotrf.f -

SYNOPSIS
Functions/Subroutines
subroutine spotrf (UPLO, N, A, LDA, INFO)
SPOTRF

Function/Subroutine Documentation
subroutine spotrf (characterUPLO, integerN, real, dimension( lda, * )A, integerLDA, integerINFO)
SPOTRF

Purpose:

SPOTRF 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.

Parameters:
UPLO

UPLO is CHARACTER*1
= 'U':  Upper triangle of A is stored;
= 'L':  Lower triangle of A is stored.

N

N is INTEGER
The order of the matrix A.  N >= 0.

A

A is REAL 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.

LDA

LDA is INTEGER
The leading dimension of the array A.  LDA >= max(1,N).

INFO

INFO is INTEGER
= 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
positive definite, and the factorization could not be
completed.

Author:
Univ. of Tennessee

Univ. of California Berkeley