Ising model

T It delay fps

GPU based Monte-Carlo simulation of the Ising model on the square 512×512 grid. it is the number of MC iterations per frame. The thermostat algorithm and linear congruential random number generator are used.

For low temperature you can watch formation of clusters of ordered phase from random state. For T > TC = 2.269 you will get desordered phase, for T < 0 the antiferromagnetic model. See Phase transitions on lattices.

Ising model. Modified chess-board algorithm

The old application uses chess-board algorithm directly. At first all independant grey spins are calculated in parallel then all white ones in the second pass (see Fig.1a and [1]). In CBA only 1/2 of shaders ("grey" or "white") are used in every pass.
To avoid spins processing in the chess-board order the odd columns are displaced as shown in Fig.1b (so you have to calculate neighbours with accurancy). Furthermore "grey" and "white" spins (texels) are stored in two different textures. Therefore modified chess-board algorithm is 2 timed faster than direct one.

[1] CPS 713 Monte Carlo Simulation for Statistical Physics
Paul Coddington, Northeast Parallel Architectures Center at Syracuse University,   Jan 1996

WebCL Demos     updated 17 Sep 2011