forked from lijiext/lammps
31 lines
715 B
Python
31 lines
715 B
Python
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#!/usr/bin/env python
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# nti.py - integrate compute fep results using the trapezoidal rule
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import sys, math
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if len(sys.argv) < 3:
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print "Thermodynamic Integration with Numerical Derivative"
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print "Trapezoidal integration of compute_fep results at equally-spaced points"
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print "usage: nti.py temperature hderiv < fep.lmp"
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sys.exit()
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hderiv = float(sys.argv[2])
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line = sys.stdin.readline()
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while line.startswith("#"):
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line = sys.stdin.readline()
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tok = line.split()
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lo = float(tok[1])
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i = 0
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sum = 0.0
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for line in sys.stdin:
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tok = line.split()
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hi = float(tok[1])
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sum += (hi + lo) / (2 * hderiv)
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lo = hi
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i += 1
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print sum / i # int_0^1: divide by i == multiply by delta
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