### 3.1.1. Running Autodyn with IBM MPI

To establish the parallel environment IBM MPI must be installed on each machine in the cluster, following the installation instructions for IBM MPI as provided in Setting up Distributed ANSYS. Users may find it necessary to set the MPI password on each machine in their cluster. To do this they can call `mpirun` with the `-cache` argument the first time they run `mpirun`, entering their user password when prompted. This argument should be removed for subsequent parallel runs.

Note: The recommended method of running an Autodyn job using IBM MPI is by using the AUTODYNWRAPPER.exe file, which is described in Running Autodyn on Windows Platforms. The following is an alternative method of starting an Autodyn parallel job using IBM MPI. This method gives you the ability to add other IBM MPI options that are not supported by AUTODYNWRAPPER.exe.

When IBM MPI is installed using the ANSYS installer, it will install IBM MPI version 9.1.4.2. The installer will set MPI_ROOT to point to this version and will add MPI_ROOT\bin to the path environment variable.

Note:

- Please refer to the MPI documentation found in your MPI installation (C:\Program Files (x86)\IBM\Platform-MPI\doc\pcmpi.win.09.01.04.01.rn.pdf for a default installation) for the description of command options such as: -cache, -pwcheck, -pass, and so on.

- Please be aware that for the Windows 7 (and higher) OS, you must disable User Account Control (UAC) on all of the machines being used for the parallel solves. To do so:

  1. In the Windows 7 Search box on the Start menu, type `UAC` and press Enter.

  2. Move the UAC settings slider to Never notify, click OK, and then reboot the machine.

Create a file called applfile. The location of the file is C:\Users\<username>\AppData\Roaming\Ansys\v182\AUTODYN. In this file enter the following text, making the relevant changes for your parallel model and machine names, and installation path, if your installation is not in the default location:

    -e MPI_FLAGS=y0 -e ANSYS_EXD_MPI_TYPE=ibmmpi -h machine1 -np 1 "C:\Program Files\ANSYS Inc\v182\AISOL\AUTODYN\
    winx64\autodyn.exe"
    -h machine1  -np 2 "C:\Program Files\ANSYS Inc\v182\AISOL\AUTODYN\winx64\adslave.exe"
    -h machine2  -np 2 "C:\Program Files\ANSYS Inc\v182\AISOL\AUTODYN\winx64\adslave.exe"

Note: If you are using the code listing example as a template for your applfile, the first and second line (the beginning and end of the Autodyn filepath) must be joined into a single line in the file in order for it to work properly.

The above applfile will launch 1 master process, 2 slaves on machine1, and 2 additional slaves on machine2.

In order to signify to the solver that the solver is running in parallel and to cross-check this with the user settings in the model file, it is required to pass the ANSYS_EXD_MPI_TYPE environment flag to the solver. The solver also cross-checks the MPI_FLAGS environment variable.

Autodyn is then started using `mpirun`. It is important that you reference the correct version of MPI, or else the wrong mpirun command is picked up from the path environment variable. This can be done globally by permanently setting the MPI_ROOT to point to version 9.1.4.2, or by temporarily changing it through a batch script.

To start Autodyn, you could call mpirun from a command prompt, but we suggest that you create a batch file in the same application data directory as the applfile file and execute that. For example, create a blank file called autodyn_mpi.bat. In this file enter:

    set MPI_ROOT=%AWP_ROOT182%\commonfiles\MPI\Platform\9.1.4.2\winx64
    "%MPI_ROOT%\bin\mpirun.exe" -prot -e MPI_WORKDIR="C:\Program Files\ANSYS Inc\v182\AISOL\AUTODYN\winx64" -f applfile

The MPI_WORKDIR text should be modified if the user’s installation of Autodyn is not in the default location.

Once the batch file is executed, the Autodyn program starts along with the number of slaves specified in applfile. The user can now create their model or load an existing one as usual.

Release 18.2 - © ANSYS, Inc. All rights reserved.