### 2.4.3. Configuring a Parallel Run

Under Run Mode, select a parallel method:

- Local Parallel Setup

- Distributed Parallel Setup

#### 2.4.3.1. Local Parallel Setup

Select a local parallel run if running a problem with two or more processors on the local machine.

Any number of partitions between 2 and 16384 can be selected. When running the job in the CFX-Solver, the computation is divided into this number of processes. For details, see Partitioner Tab. The solver enables further changes. For details, see Solver Tab.

1. Select one of the local parallel run modes (for example, `Intel MPI Local Parallel`). Which parallel run modes you can select depends on the hardware and operating system on which you are running.

2. Click Add Partition or Remove Partition to increase or decrease the number of partitions.

   Partitions may need to be configured based on partition weighting. For details, see Partitioner Tab.

#### 2.4.3.2. Distributed Parallel Setup

Select a distributed parallel option to run a problem on two or more computers.

##### 2.4.3.2.1. Overview

To configure a distributed parallel run, a file named hostinfo.ccl must exist in the <CFXROOT>/config/ CFX directory on the master node and be readable by all users of the software. This file is a database containing information about available nodes and where ANSYS CFX is installed on each of them. See hostinfo.ccl file in the Installation and Licensing Documentation (Windows) or hostinfo.ccl File in the Installation and Licensing Documentation (Linux) for more details.

Note:

- Including hosts in the hostinfo.ccl file is optional. If you want to use a host that is not present in either the hostinfo.ccl file in the <CFXROOT>/config/ directory or your own version of this file, then you can add this host to the list that is used for a particular run by using the CFX-Solver Manager as described in Selecting Parallel Hosts. However, you would have to do this each time you start a run.

- Windows users should see Setting Up IBM MPI for Windows in the Installation and Licensing Documentation for more information.

  Linux users should see ANSYS CFX Linux Parallel Setup in the Installation and Licensing Documentation for more information.

- Most distributed parallel methods have restrictions on which machines can be combined in a single distributed run. For details, see Using the Solver in Parallel in the CFX-Solver Modeling Guide.

##### 2.4.3.2.2. Selecting Parallel Hosts

You must specify a list of host machines to use for your distributed parallel run.

You can add a host from a predefined list of available hosts (which is populated by data from the hostinfo.ccl file) by clicking Insert Host .

Once you have added a host, you can configure its properties as required by clicking Create/Edit Host .

If you want to add a host that is not listed in the predefined list of available hosts, you can add a host by clicking Create/Edit Host , then entering the properties. The properties that can be set are the same as those that can be set in the hostinfo.ccl file and are described in hostinfo.ccl file in the Installation and Licensing Documentation (Windows) and hostinfo.ccl File in the Installation and Licensing Documentation (Linux). If you have a host selected when you click this icon, then the properties for that host will be displayed; however changing the Host Name causes CFX-Solver Manager to create a new entry.

Ensure that the name of the current machine is included in the list of host machines to use for your distributed parallel run.

##### 2.4.3.2.3. Configuring a Host

Each parallel host can be configured independently as follows:

1. In Parallel Environment, under Host Name, select the host to configure.

2. Click Create/Edit Host to review or change the properties for the host.

3. Click Add Partition or Remove Partition to increase or decrease the number of partitions.

   Partitions may need to be configured based on partition weighting. For details, see Partitioner Tab.

Any changes you make affect the current solver run only.

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