Lucky Lensing Library

The Lucky Lensing Library is a library and a graphical user interface for computations in the context of gravitational microlensing, an astronomical phenomenon due to the "bending" of light by massive objects.

The web home of the library is http://github.com/smarnach/luckylensing.

Features:

• High performance computations of magnification patterns by reverse ray shooting for arbitrary planar lens distributions using the thin-lens approximation. It is particularly optimised for small (< 10,000) number of lenses. Multi-threading is supported.

• Convolution of magnification patterns with source profiles. Implementations for flat and Gaussian sources are provided.

• Extraction of light curves for linear uniform source paths.

• FITS input and output.

These features are accessible through an easy-to-use Python interface or through a somewhat idiosyncratic GTK+ user interface. The ray-shooting code is written in C99.

The code is a work in progress and interfaces have not yet stabilised. There is little documentation yet, mainly in the docstrings of the Python interface. The library might still be useful for experimentation with magnification patterns though.

-- Sven Marnach (sven (a) marnach.net)

Licence

All files in the distribution are licenced under the "GNU Lesser General Public License", version 3 or -- at your option -- any later version. See the file COPYING for details.

Bugs and patches

If you find any issues, notify me on the issue tracker. Or even better, write a patch and send me a pull request.

Prerequisites

The Lucky Lensing Library should work on Unix-like platforms, though it is only tested on Linux so far.

To use the Python library, you need

• gcc (tested with versions 4.3 and 4.4)

• GNU make

• Python 2.5 or higher, includig 3.x (without the GUI)

• NumPy (probably any version will do)

For FITS I/O, you need in addition

• Astropy, version 5.0 or higher

For the GUI, you need in addition

• PyGtk

• PyGtkImageView, version 1.2 or higher

• The GUI does not work on Python 3.x

The examples additionally make use of

• Pillow, probably any recent version

Most of these dependencies are included in many Linux distributions, PyGtkImageView being an exception. I might get rid of the latter if I feel like it one day.

Installation

If you have git installed, you can clone the repository by calling

git clone git://github.com/smarnach/luckylensing.git

Alternatively, you can download a tarball of the current development version.

Then, to compile the C library, run "make" in the distribution directory. If your processor supports the SSE3 instruction set, you can consider uncommenting the corresponding line in the file luckylensing/libll/Makefile -- this will speed up the ray shooting a bit.

Getting started

Have a look at examples/planet.py for a basic ray shooting example. You can run this example by typing

cd examples/
./planet.py

(i.e. you need to be in the examples directory to run it.) The example will create a sequence of images in the examples/magpats directory visualizing the different caustic topologies for different distances between planet and star.

Also check the GUI by

cd gll/
./gll.py cluster.gll

Unfortunately, there's no documentation for the GUI so far. Don't hesitate to ask questions: (sven (a) marnach.net)

Copyright 2010 Sven Marnach