[CP2K-user] NEB - number of replicas

[tobiaskoc... at gmail.com]

Dear all,

I want to perform a nudged elastic band (NEB) calculation using cp2k.
I get the "CPASSERT failed", when I try to calculate too many replica at 
once.
Does anyone know the difference between the "Number of Images" and "Number 
of Replicas"?
Does anyone have experience, how to choose the number of processors per 
replica NPROC_REP  and the number of calculated replica  
NUMBER_OF_REPLICA   
for the best performance? 
Is there a thump rule, how many Open MP threads to use for best performance?

I tried to match the total cpu cores with nproc_rep * number_of_replica but 
the number_of_replica input seems to be ignored, instead cp2k uses the 
number of intermediate structures (replicas) as number of images.

When I use 6 replicas and 12 nproc_rep the calculation runs on the 72 core 
node.
however I set the number of replicas to 6 and provided 6 structures. CP2k 
now gives as output:

Number of Images :            6 **
 **  ##     ## ######### ##  #### ##     ##   Number of Replicas:           
1 **
 **  ##     ## ##     ## ##   ### ##     ##   Number of Procs/Rep:         
12

Why does it change the number of replicas during the run?

When I use 9 replicas and 8 nproc_rep the calculation does not run, but as 
far as I understand the input should work this way.

Best wishes 
Tobias
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