Background

HEC-WAT computations with the Flood Risk Analysis (FRA) computation option can have very long compute times. Rather than relying on a single instance of HEC-WAT, setting up and using distributed compute to leverage many virtual machines independently will shorten run times as each virtual machine can compute a portion of the total compute simultaneously.

While there are several other means to configure a distributed compute, the method outlined here and in these subpages is recommended as it is the most straight forward. The subpages will cover how the Controller and Compute Nodes need to be set up, including software installs, necessary files, and configuration settings. This was tested for WAT version 1.1 or higher.

The Controller Node and the Compute Nodes

The Distributed Compute is broken into two major pieces, the controller node and the compute nodes.  The controller node "controls" the compute nodes that are on the same port number.  The controller node sends a signal to start a compute to one of the compute nodes.  When the compute node is finished with its simulation, a signal is sent back to the controller node indicating completion and output results are saved back to the controller node for further post processing. The figure below is an example of one controller node with three compute nodes on the same port number.  

Controller Node

There is one controller node per WAT simulation and will need to be set up first. This node communicates with the distributed compute grid and assigns jobs to each compute node, presenting progress to the user, and organizing results received from the compute nodes. The user manages the controller node through the HEC-WAT interface.  Click here to set up the distributed compute plugin for the Controller.  

Compute Node

There can be many compute nodes per WAT simulation. These nodes receive jobs from the distributed compute grid, compute them, and send results back to the controller node. When the controller node sends a message to compute a WAT simulation job, the compute node starts an instance of HEC-WAT, checks to see if all of the necessary files are present in the proper locations for the project, computes the job, and reports results or failure of the compute.

You must have access to multiple computers connected to a network or virtual machine (VM).  Each Compute node also needs to have the same versions of software installed as the Controller node. This includes HEC-WAT and all software within such as HEC-HMS, HEC-ResSim, and HEC-RAS. Once you have the Controller Node set up, click here to set up the distributed compute plugin for the Compute nodes.