mirror of https://github.com/pyodide/pyodide.git
55 lines
1.4 KiB
Python
55 lines
1.4 KiB
Python
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#from https://github.com/sklam/numba-example-wavephysics
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#setup: N=100
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#run: wave(N)
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import numpy as np
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from math import ceil
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def physics(masspoints, dt, plunk, which):
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ppos = masspoints[1]
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cpos = masspoints[0]
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N = cpos.shape[0]
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# apply hooke's law
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HOOKE_K = 2100000.
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DAMPING = 0.0001
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MASS = .01
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force = np.zeros((N, 2))
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for i in range(1, N):
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dx, dy = cpos[i] - cpos[i - 1]
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dist = np.sqrt(dx**2 + dy**2)
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assert dist != 0
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fmag = -HOOKE_K * dist
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cosine = dx / dist
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sine = dy / dist
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fvec = np.array([fmag * cosine, fmag * sine])
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force[i - 1] -= fvec
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force[i] += fvec
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force[0] = force[-1] = 0, 0
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force[which][1] += plunk
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accel = force / MASS
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# verlet integration
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npos = (2 - DAMPING) * cpos - (1 - DAMPING) * ppos + accel * (dt**2)
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masspoints[1] = cpos
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masspoints[0] = npos
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#pythran export wave(int)
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def wave(PARTICLE_COUNT):
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SUBDIVISION = 300
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FRAMERATE = 60
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count = PARTICLE_COUNT
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width, height = 1200, 400
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masspoints = np.empty((2, count, 2), np.float64)
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initpos = np.zeros(count, np.float64)
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for i in range(1, count):
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initpos[i] = initpos[i - 1] + float(width) / count
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masspoints[:, :, 0] = initpos
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masspoints[:, :, 1] = height / 2
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f = 15
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plunk_pos = count // 2
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physics( masspoints, 1./ (SUBDIVISION * FRAMERATE), f, plunk_pos)
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return masspoints[0, count // 2]
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