Created
June 2, 2020 15:42
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taichi-grey-scott
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import taichi as ti | |
import numpy as np | |
import math | |
import time | |
ti.init(arch=ti.cpu) | |
screen_res = (512, 512) | |
# grey-scott paramters | |
d_a = 1 | |
d_b = 0.25 | |
mu_a = 0.0367 | |
mu_b = 0.0633 | |
# feed and kill volume | |
v_a = ti.var(ti.f32, shape=screen_res) | |
v_b = ti.var(ti.f32, shape=screen_res) | |
v_da = ti.var(ti.f32, shape=screen_res) | |
v_db = ti.var(ti.f32, shape=screen_res) | |
@ti.func | |
def saturate(x): | |
return ti.max(0, ti.min(1.0, x)) | |
@ti.func | |
def laplacian(i,j): | |
v_da[i,j] = v_a[i-1,j-1] * 0.05 + v_a[i-1,j]*0.2 + v_a[i-1,j+1]*0.05 +\ | |
v_a[i ,j-1] * 0.2 + v_a[i ,j]*-1 + v_a[i ,j+1]*0.2 +\ | |
v_a[i+1,j-1] * 0.05 + v_a[i+1,j]*0.2 + v_a[i+1,j+1]*0.05 | |
v_db[i,j] = v_b[i-1,j-1] * 0.05 + v_b[i-1,j]*0.2 + v_b[i-1,j+1]*0.05 +\ | |
v_b[i ,j-1] * 0.2 + v_b[i ,j]*-1 + v_b[i ,j+1]*0.2 +\ | |
v_b[i+1,j-1] * 0.05 + v_b[i+1,j]*0.2 + v_b[i+1,j+1]*0.05 | |
return | |
@ti.func | |
def react_diffuse(i,j): | |
v_a[i,j] += v_da[i,j]*d_a - v_a[i,j]*v_b[i,j]*v_b[i,j] + mu_a*(1-v_a[i,j]) | |
v_b[i,j] += v_db[i,j]*d_b + v_a[i,j]*v_b[i,j]*v_b[i,j] - (mu_a+mu_b)*v_b[i,j] | |
v_a[i,j] = saturate(v_a[i,j]) | |
v_b[i,j] = saturate(v_b[i,j]) | |
@ti.kernel | |
def init(): | |
for i, j in v_a: | |
v_a[i,j] = ti.random() | |
v_b[i,j] = ti.random() | |
@ti.kernel | |
def update(): | |
for i, j in ti.ndrange((1, screen_res[0] - 1), (1, screen_res[1] - 1)): | |
laplacian(i,j) | |
react_diffuse(i,j) | |
init() | |
gui = ti.GUI('Grey Scot Diffusion Reaction', screen_res) | |
while not gui.get_event(ti.GUI.ESCAPE): | |
# 5 substep | |
for i in range(0,5): | |
update() | |
image = v_a.to_numpy()*255 | |
gui.set_image(image.astype(np.uint8)) | |
gui.show() |
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