[CP2K-user] [CP2K:21010] Excessive amount of geometry points calculated in parallel VIBRATIONAL_ANALYSIS run

[Konstantin Tokarev]

Hello,

To make an efficient use of all available CPU cores I'd like to calculate 
many geometry points in parallel. If I understand properly this is a 
default behavior of cp2k when MPI-enabled build is started with mpirun. 
However, I've made a simple test with H2O molecule and discovered that for 
8 parallel processes it makes 40 SCF calculations instead of 19 which are 
performed by cp2k.ssmp. And if I use just two processes it calculates 22 
points.

I wonder if this is a bug or an expected behavior, and how would cp2k 
behave if I run vibrational analysis for a very large system on, say, 192 
CPUs? For now it seems to me like cp2k going to do a lot of unnecessary 
calculations, and it might be a better idea to stick with ssmp version and 
just do all points sequentially with OpenMP parallelism.

My input file for H2O is attached. This is a full command that I used to 
run cp2k:

numactl -N 0 --localalloc mpirun --use-hwthread-cpus --bind-to none 
--display-map -np 8 /home/enine/src/git/cp2k/exe/local/cp2k.popt -i 
H2O_b3lyp_freq.inp -o H2O_b3lyp_freq.out

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