Here I read
If no value is provided for the number of copies to execute (i.e., neither the "-np" nor its synonyms are provided on the command line), Open MPI will automatically execute a copy of the program on each process slot (see below for description of a "process slot")
So I would expect
mpirun program
to run eight copies of the program (actually a simple hello world), since I have an Intel® Core™ i7-2630QM CPU @ 2.00GHz × 8, but it doesn't: it simply runs a single process.
If you do not specify the number of processes to be used, mpirun tries to obtain them from the (specified or) default host file. From the corresponding section of the man page you linked:
If the hostfile does not provide slots information, a default of 1 is assumed.
Since you did not modify this file (I assume), mpirun will use one slot only.
On my machine, the default host file is located in
/etc/openmpi-x86_64/openmpi-default-hostfile
この記事はインターネットから収集されたものであり、転載の際にはソースを示してください。
侵害の場合は、連絡してください[email protected]
コメントを追加