README.md

gravispy

Gravitational lensing simulations written in Python.

Overview

gravispy is a small python module providing methods for simulating the distortion effects of gravitational lensing using physically accurate lensing equations.

The functions of interest are generate_lens_map and apply_lensing (see below for example usage). The submodules metrics and lensing are also used to encapsulate the available metrics and lensing algorithms. As of now, only Schwarzschild spacetimes are supported.

Example

from pathlib import Path
from PIL import Image
from gravispy import metrics, lensing, generate_lens_map, apply_lensing

schwarzschild = metrics.Schwarzschild(mass=1.0)
img = Image.open(Path('blue_marble.png'))
# The lens map is generated from a separate function call in case the results
# are intended to be used more than once. `generate_lens_map` is a very time
# consuming function.
mapping = generate_lens_map(
    lensing.spherical_lens, img.size, args=(schwarzschild, 30.0, 30e4)
)

new_img = apply_lensing(img, mapping)
new_img.save(Path('example_lensing.png'))

Input

Output

Requirements

• Sympy (version >= 1.4)

• Numpy (version >= 1.15)

• RicciPy (version >= 0.2)

• SciPy (version >= 1.4)

References

• On the exact gravitational lens equation in spherically symmetric and static spacetimes
• Spacetime perspective of Schwarzschild lensing