What is the configuration of your system? Is it a single desktop or cluster of a set of PC?

did you use all the processors?

Dear Setiadi ,

The most important parameter to speed up your calculation is to use the whole available cores on PC, Memory is not that important. it is also depend upon your crystal structure type ( large number of atoms cost more time of calculation). try to convert your crystal to primitive cell specially in cubic structure and I think tetragonal too, and (make P1) for other crystal systems. please check out the attached figure.

To reduce a memory maybe you should divide your calculation to more than one calculation as in case of band structure, phonon, non-linear response for optical properties calculations, for example for phonon calculation you can divide it to 2 calculations, one for wave function of ground state and other one for phonon(dynamical matrix). And to give your calculation more speed you can use parallelism over k-point or over band in your calculation by using more one processor.

I'm happy to help, but it's difficult to say how to speed up your CASTEP calculation without knowing more about it. How many plane-waves, bands and k-points are you using? What kind of calculation are you performing? Are you using a PC or a cluster? 100 GB is a quite a lot of RAM, do you have that in your computer or is it paging to disk?

If you're willing to post CASTEP input files (param and cell files), or send them to me privately, then I can profile the calculations and find out exactly where they are spending the time.

All the best,

Phil Hasnip

(CASTEP developer)

Thank you everyone for answering my question.

M. A. Hadi, I use single computer to calculate all of my work.

Dibya P Rai yes I tried to use all of the processor, but it took about two months to complete a single calculation.

Dear Mohammed M. Obeid, I tried to increase the usage of the processor. The problem is, not only this still took months to calculate, but it also fail by the end of the calculation with the report saying "the memory insufficient". As for the crystalline type, I do use P1 to calculate a catalyst. So I'm not sure where I did go wrong.

Raouia Ben Sadok, I didn't do the phono calculation. In my case I only want to calculate geometry optimization and see the total energy. I think the problem with my calculation is the size of the cell and the number of atoms. I'm yet to find a trick to speed things up.

Hi Philip James Hasnip, I will send you a private message to describe my calculation soon. Thank you so much for your help.

Simply, the speed of calculation can be increased by using high performance computing system (Parallel computing). However, the speed of calculation depends on the number of cores you are using for running the code. In Material Studio, you can increase the cores for calculation by following the below guidelines. A good combination of RAM and the number of cores makes a calculation so fast. However, it depends upon many others factors such as the number of K-points used, Cutoff energy etc.

file:///C:/Program%20Files/Accelrys/Materials%20Studio%207.0/share/doc/MaterialsStudio.htm#modules/castep/dlgcastepcalcjob.htm

Handi Setiadi Dear, I think you are using the wrong tool for the problem.

Nowadays unfortunately sensible calculations can be performed only on HPC.

Local computer can be used for many applications, and small system.

How big is the system you are considering? I think you are using the wrong tool and spending months on a single machine rather thatn few days on a large HPC.

Cheers,

F.

Dear Mohammed M. Obeid ,

I am using material studio in my work station laptop, i have 8 cores processor and 16 GB RAM in it. during starting my calculations, i select 6 of 8 cores, but when i check performance of my system, only 5-10 % of my system is in use.

how to increase this use?