# Giac, a free computer algebra system #

This document describes the Node port of
[Giac](http://www-fourier.ujf-grenoble.fr/~parisse/giac.html). It offers
direct use of Giac in JavaScript programs including
[Electron](https://electron.atom.io/) applications. (See the [giac-electron-example](https://github.com/kovzol/giac-electron-example)
project for a minimal example with Electron.)

## Example usage ##

```javascript
var giac = require('bindings')('giac');
console.log(giac.evaluate("expand((x+y)^3)"));
```

## Supported platforms ##

* Linux
* Mac OS X
* Windows

## Prerequisites ##

Since Giac is C++ library, you need to have a compiler toolchain on your
system installed. In addition the [GMP](https://gmplib.org) and
[MPFR](http://www.mpfr.org/) development libraries need to be present.

The compilation will be performed by
[node-gyp](https://github.com/nodejs/node-gyp). In order to install it on
your system you may have to accomplish some additional steps. In a doubt,
please consult the **node-gyp** documentation.

### Linux ###

You need a recent **gcc**. Former versions (like 4.8) may fail.

Python 2.7 is required. On some systems you may have to create a symbolic link to
the python2.7 executable (preferably as **/usr/local/bin/python**).

On a Debian based system GMP and MPFR can be installed by running `sudo apt install
libgmp-dev libmpfr-dev`.

Ubuntu 16.04 and above should work. Currently the *amd64*, *i386* and
*armhf* processors have been tested with success.

You can also compile Giac for a Raspberry Pi 3 under Raspbian Jessie. You may need at least 2 GB RAM by
[adding some swap space](https://raspberrypi.stackexchange.com/a/1605). A newer GCC will
also be required, [install GCC-6](https://solarianprogrammer.com/2016/06/24/raspberry-pi-raspbian-install-gcc-compile-cpp-14-and-cpp-17-programs/)
and then [make it default](https://askubuntu.com/a/781977/358453).

### Mac OS X ###

Install [MacPorts](https://www.macports.org/install.php) first. Then `sudo port
install gmp mpfr` will install GMP and MPFR as well.

It will be silently assumed that GMP and MPFR have been installed in /opt/local/lib.
If this is not the case, set the environment variable LIBDIR to the correct path.

Mac OS X 10.11.6 with Xcode 8.2.1, GMP 6.1.0 and MPFR 3.1.3 are known to
work correctly.

### Windows ###

At the moment only the 32 bit version works correctly. The 64 bit version may fail
for some computations.

First you need to have a working **node-gyp** installation. Please take the time
to check it by following
[Microsoft's NodeJS Guidelines](https://github.com/Microsoft/nodejs-guidelines/blob/master/windows-environment.md#compiling-native-addon-modules).

You may need Visual Studio 2013 installed, newer versions may result in strange
errors on compilation time.

It is recommended to use [MPIR](http://mpir.org/) instead of GMP. To compile the Node port of Giac the .LIB
files (that is, the static libraries) of both MPIR and MPFR will be required. You
may either compile them on your own or get the precompiled binaries. (An option
to download them is getting from [Atelier Web](http://www.atelierweb.com/mpir-and-mpfr/).
This may support only Release mode compilation.) Put the .LIB files into the current
folder, or set the LIBDIR environment variable to the correct path.

After compilation you will also need the dynamic libraries (the .DLL files). Put them
in the current folder (that is, both MPIR.DLL and MPFR.DLL) before testing/running Giac.
You may also decide to put the .DLL files in the same folder where the **giac.node**
(the artifact .DLL) file takes place.

## Compilation ##

Enter `npm install` in the current folder. Alternatively, `npm install
giac` will do the compilation by using the last stable package from the
npmjs repository. Use `npm install giac@latest` to get the latest
unstable version.

The compilation may take several minutes. To speed up the compilation
process consider entering for example
```
JOBS=4 npm install giac@latest
```
which will use 4 cores in parallel. The best value for the number of
parallel jobs is usually the number of cores you have, but
[this may depend on your system as
well](http://stackoverflow.com/questions/2499070/gnu-make-should-the-number-of-jobs-equal-the-number-of-cpu-cores-in-a-system).

### Troubleshooting ###

It may be useful to download the Node port of Giac to a local machine
and fine tune the compilation settings. This can be done as follows:
```
npm pack giac@latest
tar xzf giac*tgz
cd package
JOBS=4 npm install
npm test
```

## Testing ##

Go to your **node_modules** folder, enter `cd giac` and `npm test`. (If you are under Windows,
you need to copy the external .DLL files into this folder, or directly into the **build**
subfolder.)

To play with Giac, modify the
file **nodegiac.js** and run `npm test` again.

## Authors ##

Giac was mostly written and is continuously developed by Bernard Parisse
<bernard.parisse@univ-grenoble-alpes.fr>. The Node port was implemented
by Zoltán Kovács <zoltan@geogebra.org>.

## Acknowledgments ##

The Node port of Giac is dedicated to [Gábor Ancsin](https://www.geogebra.org/gabor), one of the most
prominent JavaScript heroes of the [GeoGebra](http://www.geogebra.org)
[Team](http://www.geogebra.org/team).
