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NAME
     dpotf2 - compute the Cholesky factorization of a  real  sym-
     metric positive definite matrix A

SYNOPSIS
     SUBROUTINE DPOTF2( UPLO, N, A, LDA, INFO )

     CHARACTER UPLO

     INTEGER INFO, LDA, N

     DOUBLE PRECISION A( LDA, * )



     #include <sunperf.h>

     void dpotf2(char uplo, int  n,  double  *da,  int  lda,  int
               *info) ;

PURPOSE
     DPOTF2 computes the Cholesky factorization of  a  real  sym-
     metric positive definite matrix A.

     The factorization has the form
        A = U' * U ,  if UPLO = 'U', or
        A = L  * L',  if UPLO = 'L',
     where U is an upper triangular matrix and L  is  lower  tri-
     angular.

     This is the unblocked  version  of  the  algorithm,  calling
     Level 2 BLAS.


ARGUMENTS
     UPLO      (input) CHARACTER*1
               Specifies whether the upper  or  lower  triangular
               part  of the symmetric matrix A is stored.  = 'U':
               Upper triangular
               = 'L':  Lower triangular

     N         (input) INTEGER
               The order of the matrix A.  N >= 0.

     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 con-
               tains 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'*U  or A = L*L'.

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

     INFO      (output) INTEGER
               = 0: successful exit
               < 0: if INFO = -k, the k-th argument had an  ille-
               gal value
               > 0: if INFO = k, the leading minor of order k  is
               not positive definite, and the factorization could
               not be completed.

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