42 lines
1.2 KiB
Python
42 lines
1.2 KiB
Python
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import numpy as np
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#def project(a, b): # projects b onto the unit cube, using a as an offset origin
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# a = np.asanyarray(a)
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# b = np.asanyarray(b)
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# d = b - a
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# if all(np.abs(d) <= 1e-8):
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# return a
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# inner = -1 / np.where(np.abs(d) > 1e-8, d, np.where(d >= 0, 1e-8, -1e-8))
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# small = np.minimum(1 - a, a - 1)
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# large = np.maximum(0 - a, a - 0)
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# rescale = np.min(np.maximum(inner * small, inner * large))
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# assert np.isfinite(rescale), rescale
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# if rescale < 1:
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# return a + (rescale - 1e-6) * d
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# else:
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# return b
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def project(p, a, eps=1e-8):
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# https://www.desmos.com/calculator/gdcu0ivk0i
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p = np.asanyarray(p)
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a = np.asanyarray(a)
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d = p - a
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if all(np.abs(d) <= eps):
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# we might still be inching out of bounds, so just to be sure:
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a[a <= 0] = 0
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a[a >= 1] = 1
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return a
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inner = 1 / np.where(np.abs(d) > eps, d, np.where(d >= 0, eps, -eps))
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small = -np.abs(p - 1) # np.minimum(1 - p, p - 1)
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large = np.abs(p) # np.maximum(0 - p, p - 0)
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rescale = np.min(np.maximum(inner * small, inner * large))
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if rescale <= 1:
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b = p - max(0, rescale - 1e-8) * d
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return b
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else:
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return a
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