25 lines
503 B
Python
Executable File
25 lines
503 B
Python
Executable File
#!/usr/bin/env python
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# fep.py - calculate free energy from compute fep results
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import sys
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import math
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if len(sys.argv) < 2:
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print("Free Energy Perturbation")
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print("usage: fep.py temperature < out.fep")
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sys.exit()
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rt = 0.008314 / 4.184 * float(sys.argv[1]) # in kcal/mol
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v = 1.0
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sum = 0.0
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for line in sys.stdin:
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if line.startswith("#"):
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continue
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tok = line.split()
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if len(tok) == 4:
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v = float(tok[3])
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sum += math.log(float(tok[2]) / v)
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print(-rt * sum)
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