*NOTE: This is still a work in progress.*

# gsl-lua: A Lua binding for the GNU Scientific Library

## Introduction

**gsl-lua** is a numerical package based on the GSL library. It exposes a simple interface to some of the GSL library routines and data types.

GSL data types are integrated by providing wrapper objects that can be naturally operated upon from Lua; in addition, some degree of natural manipulation is provided for vectors and matrices. For instance, it supports arithmetic operators on vectors and matrices, interpolating and fitting functors, numerical integration, and more. Therefore, code such as the following can be written:

-- Creates two vectors with the given elements x = gsl.Vector{1, 2, 5, 9, 15} y = gsl.Vector{5, 6, 7, 8, 10} print(x[1], x[4]) -- prints 1, 9 -- Vector operations a = x + y -- a = |6, 8, 12, 17, 25| b = x * y -- b = |5, 12, 35, 72, 150| print(gsl.Vector{3, 4}:norm()) -- prints 5 c = a['@[i] > 15'] -- c = |17, 25|; selects all elements larger than 15 d = a:map('i <= 3', '@[i]^2') -- d = |36, 64, 144|; selects first 3 elements and square them -- Fits poly3 = gsl.fit.poly(3) -- a third degree polynomial fit = gsl.lsfit({x, poly3}, y, nil, "fmulti") -- fits x and y with poly3 print(fit:coeffs(), fit:chisq()) -- |4.887, 4.180e-1, -5.387e-3| 2.52e-1

Currently, it includes support for vectors and matrices,

numerical integration, interpolation and least-squares fitting. The GSL library functions are called using the Alien. The large majority of the library is written in Lua and easy to extend.

gsl-lua has been tested with Lua 5.1.4 and LuaJIT 2.0 (beta 6).

## Installation

This module requires the following libraries to be installed in the Lua module searchpath:

Compile src/gslsupport.c as a library and place it in your library path, so that it can be found by Alien (e.g. /usr/local/lib):

```
// Unix
gcc -static -std=c99 -o gslsupport.so gslsupport.c
// on Mac OS X
gcc -undefined dynamic_lookup -dynamiclib -std=c99 -o gslsupport.dylib gslsupport.c
```

Finally, place the gsl.lua and GSLdefs2.lua in your Lua module searchpath (e.g. /usr/local/share/lua/5.1).

## License

gsl-lua is a wrapper for GSL, therefore inherits the GPL licence.