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42 lines
1.1 KiB
Python
42 lines
1.1 KiB
Python
import numpy as np
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from Link import Link
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class RubberBand:
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# class attributes
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k_B = 1
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def __init__(self, N, a=1., T=1.):
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"""
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RubberBand is a class that can simulate a rubber band with N
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incompressible links of length a.
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Parameters:
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N (int) The number of links.
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a (float) The fixed length of links.
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T (float) Temperature of the system.
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"""
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self.N = N
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self.a = a
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self.T = T
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self.links = self.__sample_links()
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def w(self, f, l):
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beta = (self.k_B*self.T)**(-1)
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return np.exp(beta*f*l)
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@property
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def length(self):
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return self.a * np.sum([l.direction for l in self.links])
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def __sample_links(self):
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"""
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Sample N Link objects with a random direction.
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"""
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samples = np.random.random_sample((self.N,))
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directions = np.ones(samples.shape)
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directions[samples < 0.5] = -1.
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directions = directions.astype(int)
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return [Link(d) for d in directions] |