Intro

This project collects examples of using MATLAB Coder to generate C code and bringing into another language. The languages shown here are C#, Java, and Python. SWIG, a software development tool that connects programs written in C and C++ with a variety of high-level programming languages, is used to perform this interfacing.

Each subdirectory contains a separate example with:

• MATLAB computational code
• A SWIG interface file
• MATLAB scripts to call codegen, invoke SWIG, and build the resultant code for each language. E.g.: doitCsharp.m, doitJava.m, doitPython.m, etc.
• Example C#, Java, and Python main functions using the generated C and SWIG code

Getting started

There are a set of beginning examples based on a simple timestwo function that are a good starting point. Follow them in numeric order to see progressively increasing complexity.

• 01-timestwo-scalar: Simple scalar input, scalar output example that multiplies the input by 2
• 02-timestwo-fixed-size: Element-wise multiplication by 2 with fixed size matrix input/output
• 03-timestwo-dynamic-size: Element-wise multiplication by 2 with variable size, dynamically allocated input/output

Recipe for using MATLAB Coder and SWIG

1. Generate code using MATLAB Coder.

2. Inspect the generated interface header foo.h to see the signature of the generated code.

3. Construct your SWIG interface file. For scalar inputs/outputs, this file will be trivial, just referencing necessary generated API headers like 01-timestwo-scalar/timestwo.i. For more complicated interfaces with variable size inputs, structs, etc. the interface file will be more complex like 03-timestwo-dynamic-size/timestwo.i. Include declarations for the emxArray types used in the generated code interface.

   In all of the non-scalar examples the SWIG carrays.i interface to wrap array data efficiently without copies. For a more idiomatic interface see other options that SWIG provides.

4. To run SWIG and compile the generated code and SWIG wrapper during the MATLAB Coder build process, construct your Coder build hook (e.g. csharphook.m). You can also compile the SWIG wrapper outside of MATLAB Coder.

5. Set that as the Coder PostCodeGenCommand: cfg = coder.config('dll'); cfg.PostCodeGenCommand = 'csharphook';

Requirements

This is tested with MATLAB R2018a on Ubuntu and Debian and requires:

• SWIG
• A Java JDK
• Mono command-line development tools
• Python development headers, libraries, and tools
• C or C++ build tools

apt install swig build-essential default-jdk mono-mcs python2.7-dev python-dev