AMBER Archive (2002)

Subject: Re: "number of processors must be a power of two"

From: David A. Case (case_at_scripps.edu)
Date: Tue Aug 06 2002 - 11:40:33 CDT

On Tue, Aug 06, 2002, Jim wrote:
>
> number of processors must be a power of 2, and no greater than 128:

This is a message generated by sander; with the (default) BTREE option in
version 7, the number of processors indeed must be a power of 2. It has
nothing to do with your MPI implementation.

You can remove this restriction by adding "-DnoBTREE" to your MACHINEFLAGS
variable (in the MACHINE file) and re-compiling. This change might not
even cost much in performance if your MPI has a good implementation of global
gather/scatters (MPICH does not have very efficient implementations here.)

..hope this helps...dac 

-- 

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