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

From: David A. Case <>
Date: Tue 6 Aug 2002 09:40:33 -0700

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

David A. Case                     |  e-mail:
Dept. of Molecular Biology, TPC15 |  fax:          +1-858-784-8896
The Scripps Research Institute    |  phone:        +1-858-784-9768
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Received on Tue Aug 06 2002 - 09:40:33 PDT
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