[Pw_forum] what is the meaning of the error " error in DGETRF"

[y.k. zhou]

On 12/15/05, 针叶 朱 <coldwind1978 at yahoo.com.cn> wrote:
> Dear All users:
>  i am new users, when i relax supperlattice "BaTiO3/SrTiO3", the error
> appeared:  from invmat : error #         2
>                 error in DGETRF
> ,please tell me why?
>

Hi,  dgetrf is a LAPACK subroutine for
LU factorization of a general matrix using
partial pivoting with row interchanges.

The output value of info for
SUBROUTINE DGETRF( M, N, A, LDA, IPIV, INFO )
is commented (in the source code) as:

*  INFO    (output) INTEGER
*          = 0:  successful exit
*          < 0:  if INFO = -i, the i-th argument had an illegal value
*          > 0:  if INFO = i, U(i,i) is exactly zero. The factorization
*                has been completed, but the factor U is exactly
*                singular, and division by zero will occur if it is used
*                to solve a system of equations.

regards,

-ykz