VMC file format: virtual machine configuration for distributed parallel optimization

File format to specify a virtual machine configuration for distributed parallel optimization

A virtual machine configuration (VMC) file is an XML file that specifies the communication protocol between a master and the workers, as well as the configuration of each worker (one entry per worker) in a distributed parallel optimization application. CPLEX accepts VMC files to specify a virtual machine configuration for distributed parallel optimization.

DTD and XSD for VMC files

To assist you in creating such a file yourself, your installation of the product includes a document type definition (DTD) <Install_dir>/cplex/include/ilcplex/vmc.dtd and an XML schema declaration (XSD) <Install_dir>/cplex/include/ilcplex/vmc.xsd.

Environment variables in VMC files

CPLEX expands an environment variable cited in a VMC file at the time that CPLEX reads the VMC file. Reference to an environment variable must be of the form:


$(name)

In particular, CPLEX does not recognize $name nor ${name}. CPLEX interprets the character sequence $$ as a single $. This convention means that you can produce verbatim $( by writing $$(.

Sample VMC files

For samples of this file format in use, see these topics in the CPLEX User's Manual:

Generating a VMC file in the Interactive Optimizer

During a session of the Interactive Optimizer, you can generate a configuration file for virtual machines used as master and workers, based on the transport protocol that you are using. For example, if you have created a cluster of master and workers in the Message Passing Interface (MPI) transport protocol, then from a session of the Interactive Optimizer, you can let CPLEX generate a VMC file from that MPI environment, like this:


set distmip config mpi