Helios

Helios is a python library implemented in C for layouting and visualizing complex networks.

Layout

Helios implements a force layout algorithm based on the FR algorithm [1].

Install

Requires python headers and a C11 compatible compiler, such as gcc or clang.

To install it, simply run:

pip install helios

or clone this repository and install it from master by running:

pip install git+git://github.com/heliosnet/helios-core.git

Usage

Currently only the FR layout interface is implemented.

Example initialization with a small network.

import numpy as np
import helios

positions = np.random.random((4, 3))

edges = np.array([
  [0,1],
  [2,3]
],dtype=np.uint64)

# positions is required to be an contiguous float32 numpy array
positions = np.ascontiguousarray(positions,dtype=np.float32)

# edges is required to be an contiguous uint64 numpy array
edges = np.ascontiguousarray(edges,dtype=np.uint64)

# speeds is required to be an contiguous uint64 numpy array
speeds = np.zeros(positions.shape,dtype=np.float32)

layout = helios.FRLayout(edges,positions,speeds)

Two APIS are available to iterate the layouts, synchronized and aynchronous.

Example of the synchronized API:

print("Initial positions:")
print(layout.positions)
layout.iterate(iterations=100)
print("Final positions:")
print(layout.positions)

Example using the aynchronous API:

print("Initial positions:")
print(layout.positions)
if(layout.running()): #False
  print("It is running...")
else:
  print("Not running...")
layout.start()
time.sleep(1)
print("Current positions:")
print(layout.positions)
time.sleep(1)
print("Current positions:")
print(layout.positions)
if(layout.running()): #True
  print("It is running...")
else:
  print("Not running...")
layout.stop()
print("Final positions:")
print(layout.positions)

You can restart the layout once it stopped. Subsequent calls to the start method have no effect if the layout is running.

References

[1] Fruchterman, T. M. J., & Reingold, E. M. (1991). Graph Drawing by Force-Directed Placement. Software: Practice and Experience, 21(11).