Compare energy

gistfile1.py

from __future__ import print_function
import simtk.openmm as mm
import simtk.openmm.app as app

d = dict(base_dir="RUN2",
         state='state.xml')


with open("{base_dir}/system.xml".format(**d)) as f:
    system = mm.XmlSerializer.deserialize(f.read())

with open("{base_dir}/{state}".format(**d)) as f:
    state = mm.XmlSerializer.deserialize(f.read())

e_serial = state.getPotentialEnergy()
print("Serialized:", e_serial)

with open("{base_dir}/integrator.xml".format(**d)) as f:
    integrator = mm.XmlSerializer.deserialize(f.read())
platform = mm.Platform.getPlatformByName("Reference")
context = mm.Context(system, integrator, platform)
context.setState(state)
platform = context.getPlatform()
e_ref = context.getState(getEnergy=True).getPotentialEnergy()
print(platform.getName(), e_ref)
del context, platform, integrator

with open("{base_dir}/integrator.xml".format(**d)) as f:
    integrator = mm.XmlSerializer.deserialize(f.read())
platform = mm.Platform.getPlatformByName("OpenCL")
context = mm.Context(system, integrator, platform, {'OpenCLDeviceIndex': '0'})
dev_name = platform.getPropertyValue(context, 'OpenCLDeviceName')
context.setState(state)
platform = context.getPlatform()
e_cl0 = context.getState(getEnergy=True).getPotentialEnergy()
print(platform.getName(), dev_name,  e_cl0)
del context, platform, integrator

with open("{base_dir}/integrator.xml".format(**d)) as f:
    integrator = mm.XmlSerializer.deserialize(f.read())
platform = mm.Platform.getPlatformByName("OpenCL")
context = mm.Context(system, integrator, platform, {'OpenCLDeviceIndex': '1'})
dev_name = platform.getPropertyValue(context, 'OpenCLDeviceName')
context.setState(state)
platform = context.getPlatform()
e_cl1 = context.getState(getEnergy=True).getPotentialEnergy()
print(platform.getName(), dev_name,  e_cl1)
del context, platform, integrator

diff = e_cl0 - e_ref
print("Diff:", diff)

diff = e_cl1 - e_ref
print("Diff:", diff)