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chdthanh
Beginner
31 Views

Number of processors

Does Intel Core 2 Duo mean 2 processors?
When I use MPI subroutine MPI_COMM_SIZE I got size=1. Does it means that there are 1 processors?Andthe reason is that I useWinXP 32-bit?
Can you please tell how to use 2 processors?
Thanks,
Thanh

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2 Replies
TimP
Black Belt
31 Views

No, MPI_COMM_SIZE doesn't tell anything about the number of processors, under either of the common definitions. Core 2 Duo is certainly capable of running 2 MPI ranks, or 2 OpenMP threads, even under XP32. Did you start your job by mpirun -np 2 or similar ?
MPI implementations, in my experience, never pick a number of ranks automatically, unlike OpenMP, where some implementation default to 1 thread, and others default to total number of cores or logicals.
Intel like to call a Core 2 Duo a single processor dual core, even though the term logical processors also is used, particularly for HT. Many MPI users consider dual core as 2 processors.
chdthanh
Beginner
31 Views

Thanks for your explanation