[Pw_forum] error in gamma

Paolo Giannozzi giannozz at democritos.it
Thu Jun 10 13:44:20 CEST 2010

kazempoor at ph.iut.ac.ir wrote:

>      from  pzpotrf  : error #        47
>       problems computing cholesky decomposition
> This is very strange because when I set nbnd=512
 > the pw1.in and pw2.in run without any problem .

it is not strange. The diagonalization algorithm in PWscf
is expected to work for a number of bands that is much
smaller than the dimension of the basis set. It usually
works great if you calculate occupied bands and a few
unoccupied bands. The more bands you add, the more you
are likely to run into numerical trouble. The error
here occurs in a Scalapack routine (pzpotrf). Finding
out why and how is a highly nontrivial task

Paolo Giannozzi, Democritos and University of Udine, Italy

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