Parameters about parallelism

[Abinit]

Dear Abinit users,

I am doing calculations on big systems, so parallel calculations should be employed.

In tutorial I found several parameters related to the parallelization. If I don't care about the efficiency, I could just set autoparal=1. However, with paral_kgb=1 and autoparal=0, I could divided the number of processors on different levels, which are controled by npfft, npkpt, npspinor, npband, and bandpp. In order to set these parameters, several constrains should be considered:
1). npkpt*npfft*npband*npspinor=nproc;

2). nband should be a multiple of npband*bandpp;

3). bandpp should be either 1 or a multiple of 2.

The system is unpolarized, so npspinor could be kept 1.

Despite of these constrains, the degree of freedom of setting these parameters is still large. I wonder if there is other constrains I overlooked and if there is a usual way to set these parameters and choose proper number of processors to gain a good efficiency for the calculation.

For an example, the default number of band to be calculated is nband=497, and the maximum processors of each calculation node is 28, with total k points 32 respect to a 10*10*1 k point mesh. Could anyone please tell me how I should choose the parallel parameters: npkpt, npfft, npband, and bandpp?

Any hint for this will be welcome.

Best regards
Zhishuo Huang

[ebousquet]

Dear Zhishuo Huang
Did you see this post I made some time ago about parallel parameters:
https://forum.abinit.org/viewtopic.php?f=8&t=3837
Let me know if this not enough for you.
Best wishes,
Eric