User`s guide

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2.5. Setting up the Intel® MPI Library Environment
The Intel® MPI Library uses the Hydra process manager. To run programs compiled with the
mpiicc (or related) commands, make sure your environment is set up correctly.
1. Set up the environment variables with appropriate values and directories. For example, in the
.cshrc or .bashrc files:
 Ensure that the PATH variable includes the <installdir>/<arch>/bin directory. Use the
mpivars.[c]sh scripts included with the Intel MPI Library to set up this variable.
 (SDK only)If you are using the Intel® Composer XE packages, ensure that the
LD_LIBRARY_PATH variable contains the directories for the compiler library. To set this
variable, run the compilervars.[c]sh scripts included with the compiler.
 Set any additional environment variables that your application uses.
2. Make sure that every node can connect to any other node without a password.
3. Create a hostfile text file that lists the nodes in the cluster using one host name per line.
For example:
$ cat
> hostfile
node1
node2
...
<ctrl> -D
2.6. Selecting a Network Fabric
The Intel® MPI Library dynamically selects the most appropriate fabric for communication between
MPI processes. To select a specific fabric combination, set the I_MPI_FABRICS environment
variable.
2.6.1. I_MPI_FABRICS
Select a particular network fabric to be used for communication.
Syntax
I_MPI_FABRICS=<fabric>|<intra-node fabric>:<inter-nodes fabric>
Where
 <fabric> := {shm, dapl, tcp, tmi, ofa}
 <intra-node fabric> := {shm, dapl, tcp, tmi, ofa}
 <inter-nodes fabric> := {shm, tcp, tmi, ofa}