Introduction

What Ria does

The Ria library solves constraint problems over the reals. It is not limited to linear constraints. So it can be used to solve general problems like:

[eclipse 2]: ria:(ln(X) >= sin(X)).

X = X{0.36787944117144233 .. Infinity}
yes.

The Ria library has two different algorithms built in. The default one is arc-consistency and is quite cheap, the other provides a stronger consistency but is slower.

Both algorithms work on the same data representation. That is real numbers in a closed range between (and including) two floats. The library will reduce this range if possible. It never gets as far as reducing a variable to a single float.

Usage

Load the library by using

:- lib(ria).

History

This work was triggered by the work of Slava Zilberfaine from the Novosibirsk Institute of Informatics Systems on an interface between ECLiPSe and Unicalc. A subset of this functionality was later provided as lib(ria), which does not share any code with Unicalc.