[Pw_forum] memory problem

[Paolo Giannozzi]

Prasenjit Ghosh wrote:

>      per-process dynamical memory:   507.1 Mb
>      per-process dynamical memory:  1867.8 Mb

what happens in the middle?

 > Oct 31 13:49:45 2008 13128 4 7.02 handleTSRegisterTerm(): TS reports
 > task <0> pid <30753> on host<node0833> killed or core dumped
 > [...] Can any one please let me know why the job is getting killed?

of course, nobody can

> Is it due to some memory problem?

good guess

> For the same job why does the memory requirement go on increasing?

during a single scf step, the amount of required memory can increase,
but each scf step should take more or less always the same maximum 
memory. It is impossible to say more without at least a complete
output. It might be a memory leak, which might come from a bug either
in the code or in the compiler or libraries.

> Also, can you please let me know how the code calculates the memory  
> requirement? 

with an appropriate (?) system library call. Calculating memory usage
in modern operating systems is a nontrivial task, so you have to hope
that what you get is a meaningful approximation to occupied dynamical
matrix (the static memory, i.e. the code itself including static arrays,
is typically small and can be estimated using "size pw.x" for instance)

Paolo
-- 
Paolo Giannozzi, Democritos and University of Udine, Italy