Polyglot Programming

TornadoVM can be used with the GraalVM Truffle Polyglot API to invoke Task-Graphs from guest programming languages such as Python, R, etc.. This guide will describe how to execute TornadoVM programs through code written in Python, JavaScript, and R.

1. Prerequisites

A) Configuration of the JAVA_HOME Variable

To enable polyglot support, the JAVA_HOME variable must be set to the GraalVM path. Instructions on how to install TornadoVM with GraalVM can be found here: Installation for GraalVM 22.3.2 on Linux and OSx.

B) GraalVM Polyglot Dependencies

As detailed in the GraalVM Reference Manuals, the following dependencies must be downloaded for each of the programming languages supported:

  • Python

$JAVA_HOME/bin/gu install python

  • JavaScript

$JAVA_HOME/bin/install js

  • R

$JAVA_HOME/bin/gu install r

2. Executing a TornadoVM program through Graal’s Polyglot API

In the following example, we will iterate over the necessary steps to invoke a TornadoVM computation from Python, JavaScript and R programs, using the MyCompute class from the TornadoVM examples module. However, users can create their own Java classes with the code to be accelerated following the TornadoVM API guidelines Core Programming.

  • Step 1:

    Create a variable that is of the Java class type.

    Python

    myclass = java.type('uk.ac.manchester.tornado.examples.polyglot.MyCompute')

    JavaScript

    var myclass = Java.type('uk.ac.manchester.tornado.examples.polyglot.MyCompute')

    R

    myclass <- java.type('uk.ac.manchester.tornado.examples.polyglot.MyCompute')
  • Step 2:

    Use this variable to invoke the Java function that contains the Task-Graph. In this example, the function is named compute().

    Python

    myclass.compute()

    JavaScript

    myclass.compute()

    R

    myclass$compute()
  • Step 3:

    Execute the R/JavaScript/Python program through TornadoVM. The polyglot program can be executed using the tornado command, followed by the --truffle option and the language of the program.

    E.g.,

    $ tornado --truffle r|python|js <path/to/polyglot/program>

All of the existing TornadoVM options (e.g., --printKernel, etc.) can be used as always.

3. Testing

The tornado-assembly/scr/example/polyglotTruffle directory contains three examples, one for each of the supported languages. These examples can be executed using the polyglotTests.sh script.

$ ./scripts/polyglotTests.sh