Introduction

What is AMPL API?

AMPL API is an interface that allows developers to access the features of the AMPL interpreter from within a programming language. All model generation and solver interaction is handled directly by AMPL, which leads to great stability and speed; the library just acts as an intermediary, and the added overhead (in terms of memory and CPU usage) depends mostly on how much data is read back from AMPL, the size of the model as such is irrelevant. Functions for directly assigning data to AMPL parameters and sets are provided, which can be used instead of the normal AMPL data reading procedures. AMPL API has been written with usability in mind, and it is easy to access its functionalities from C++, Java, MATLAB, C#, Python and R.

Who can use AMPL API

The intended user of the library is the developer who needs to connect an application to optimization models and solvers, or the analyst with some experience in programming who wants to build a quick proof-of-concept application. Architecture schema of AMPLAPI below shows a possible architecture and a sequence of interaction between a decision support system relying on an existing IT framework and AMPL API.

Architecture Schema

Architecture schema of AMPLAPI

System requirements

As AMPL API uses AMPL for model generation, the AMPL executable is needed and is generally provided. The solution is then obtained through external solvers. In general, an updated R setup with Rtools are necessary and sufficient conditions for the correct execution of AMPL API. The officially supported platforms are all Windows flavours, various Linux 32/64 bits and OSX. Ports to any other platform supported by AMPL can be easily obtained.

About this manual

This document intends to guide a developer in the process of implementing an “AMPL API based” application in R. The section Class structure presents the main logic of the API, which does not change depending on which programming environment is chosen. Further sections walk the reader through the implementation of the most common applications, finally the sections R API reference and R API examples contain respectively the API reference documentation and a collection of examples.