HP-MPI Version 2.2.5 for Linux Release Note

HP-MPI V2.2.5 for Linux Release Note

What’s in This Version

Each of the above arguments may be combined with an optional rank count '-np N' which, if

present, will select exactly N ranks. The ranks are selected by traversing the

list|file|env-vars of hosts in order with wraparound if the requested number of ranks exceeds

the number of hosts. If the number of desired ranks is not specified, then the

list|file|env-vars are traversed once to produce a complete list of hosts.

-hostlist <quoted-host-list> where <quoted-host-list> is one or more hosts separated

by spaces or commas and hosts can have a trailing count designated with :<N> or a trailing

count.

To launch an MPI job with 4 ranks on host n1 and 2 ranks on host n2:

-hostlist "n1 4 n2 2"

-hostlist "n1:4 n2:2"

By default, the -hostlist option will launch exactly M ranks where M is computed by

examining the contents of the option to -hostlist and totalling the number of requested

hosts and instances of ranks per host.

The default number of ranks can be overridden through the use of the -np <count> option

which will launch exactly <count> number of ranks. If necessary, the hostlist is scanned again

from the beginning to supply additional hosts.

For example, to launch 12 ranks on hosts n2 and n3:

-np 12 -hostlist "n2:4 n3:3"

The -np <count> option can also be used to restrict the number of ranks to less than the

number described in the option to -hostlist. For example:

-np 3 -hostlist "n1 n2 n3 n4"

In the above example, -np 3 restricts the job to 3 ranks from the hostlist "n1 n2 n3 n4", so 1

rank will be launched on each of n1, n2, and n3.

-hostfile <filename> is a text file with hostnames separated by spaces or new lines. Each

hostname may have an optional count field.

Assuming hfile contains

n1 2

#n2

n3 3

-np 4 -hostfile hfile

# 2 ranks on n1 and 2 ranks on n3.

-np 6 -hostfile hfile

# 2 ranks on n1, 3 ranks on n3, and one more on n2.