			#!/usr/bin/env python
			# nti.py - integrate compute fep results using the trapezoidal rule

			import sys, math

			if len(sys.argv) < 3:
			print "Thermodynamic Integration with Numerical Derivative"
			print "Trapezoidal integration of compute_fep results at equally-spaced points"
			print "usage: nti.py temperature hderiv < fep.lmp"
			sys.exit()

			hderiv = float(sys.argv[2])

			line = sys.stdin.readline()
			while line.startswith("#"):
			line = sys.stdin.readline()

			tok = line.split()
			lo = float(tok[1])

			i = 0
			sum = 0.0
			for line in sys.stdin:
			tok = line.split()
			hi = float(tok[1])
			sum += (hi + lo) / (2 * hderiv)
			lo = hi
			i += 1

			print sum / i # int_0^1: divide by i == multiply by delta

lammps/tools/fep/nti.py
d58afbcc48falammm-devel

nti.py
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