wehub-resource-sync
72 lines
1.6 KiB
Python
Executable File
72 lines
1.6 KiB
Python
Executable File
import numpy as np
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from prml.rv.rv import RandomVariable
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class Uniform(RandomVariable):
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"""
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Uniform distribution
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p(x|a, b)
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= 1 / ((b_0 - a_0) * (b_1 - a_1)) if a <= x <= b else 0
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"""
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def __init__(self, low, high):
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"""
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construct uniform distribution
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Parameters
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----------
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low : int, float, or np.ndarray
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lower boundary
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high : int, float, or np.ndarray
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higher boundary
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"""
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super().__init__()
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low = np.asarray(low)
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high = np.asarray(high)
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assert low.shape == high.shape
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assert (low <= high).all()
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self.low = low
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self.high = high
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self.value = 1 / np.prod(high - low)
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@property
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def low(self):
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return self.parameter["low"]
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@low.setter
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def low(self, low):
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self.parameter["low"] = low
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@property
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def high(self):
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return self.parameter["high"]
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@high.setter
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def high(self, high):
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self.parameter["high"] = high
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@property
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def ndim(self):
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return self.low.ndim
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@property
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def size(self):
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return self.low.size
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@property
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def shape(self):
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return self.low.shape
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@property
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def mean(self):
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return 0.5 * (self.low + self.high)
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def _pdf(self, X):
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higher = np.logical_and.reduce(X >= self.low, 1)
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lower = np.logical_and.reduce(X <= self.high, 1)
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return self.value * np.logical_and(higher, lower)
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def _draw(self, sample_size=1):
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u01 = np.random.uniform(size=(sample_size,) + self.shape)
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return u01 * (self.high - self.low) + self.low
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