mirror of https://github.com/pyodide/pyodide.git
57 lines
1.9 KiB
Python
57 lines
1.9 KiB
Python
#from: http://continuum.io/blog/numba_performance
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#setup: N = 10 ; import numpy as np ; image = np.random.rand(N, N, 3) ; state = np.zeros((N, N, 2)) ; state_next = np.empty_like(state) ; state[0, 0, 0] = state[0, 0, 1] = 1
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#run: growcut(image, state, state_next, 2)
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#pythran export growcut(float[][][], float[][][], float[][][], int)
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import math
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import numpy as np
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def window_floor(idx, radius):
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if radius > idx:
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return 0
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else:
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return idx - radius
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def window_ceil(idx, ceil, radius):
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if idx + radius > ceil:
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return ceil
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else:
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return idx + radius
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def growcut(image, state, state_next, window_radius):
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changes = 0
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sqrt_3 = math.sqrt(3.0)
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height = image.shape[0]
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width = image.shape[1]
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for j in range(width):
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for i in range(height):
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winning_colony = state[i, j, 0]
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defense_strength = state[i, j, 1]
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for jj in range(window_floor(j, window_radius),
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window_ceil(j+1, width, window_radius)):
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for ii in range(window_floor(i, window_radius),
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window_ceil(i+1, height, window_radius)):
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if (ii != i and jj != j):
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d = image[i, j, 0] - image[ii, jj, 0]
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s = d * d
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for k in range(1, 3):
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d = image[i, j, k] - image[ii, jj, k]
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s += d * d
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gval = 1.0 - math.sqrt(s)/sqrt_3
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attack_strength = gval * state[ii, jj, 1]
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if attack_strength > defense_strength:
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defense_strength = attack_strength
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winning_colony = state[ii, jj, 0]
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changes += 1
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state_next[i, j, 0] = winning_colony
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state_next[i, j, 1] = defense_strength
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return changes
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