The octave-forge package is the result of The GNU Octave Repositry project,
which is intended to be a central location for custom scripts, functions and
extensions for GNU Octave. contains the source for all the functions plus
build and install scripts.

This is interval.

 The interval package for real-valued interval arithmetic allows to evaluate
 functions over subsets of their domain. All results are verified, because
 interval computations automatically keep track of any errors. These
 concepts can be used to handle uncertainties, estimate arithmetic errors
 and produce reliable results. Also it can be applied to computer-assisted
 proofs, constraint programming, and verified computing. The implementation
 is based on interval boundaries represented by binary64 numbers and is
 conforming to IEEE Std 1788-2015, IEEE standard for interval arithmetic.

WWW: http://octave.sourceforge.net/