def testForce(self):
lj = LennardJones(epsilon=2.0, sigma=2.0)
# force in the minimum
self.assertAlmostEqual(
(lj.computeForce(2.0 * 2.0**(1.0 / 6.0), 0.0, 0.0) -
Real3D(0.0, 0.0, 0.0)).sqr(), 0)
def testProperties(self):
lj = LennardJones()
lj.epsilon = 2.0
lj.sigma = 2.0
lj.cutoff = 4.0
lj.shift = 0.0
# here we test energy computation, as testing property access
# would always work
self.assertAlmostEqual(lj.computeEnergy(2.0), 0.0)
self.assertAlmostEqual(lj.computeEnergy(2.0 * 2.0**(1.0 / 6.0)), -2.0)
def test0Create(self):
lj = LennardJones(1.0, 2.0, 3.0)
self.assertEqual(lj.epsilon, 1.0)
self.assertEqual(lj.sigma, 2.0)
self.assertEqual(lj.cutoff, 3.0)
# now read the file log.out and find "DEBUG" and "potential"
f = open(filename, "r")
s = f.read()
self.assert_(s.find("_espressopp.interaction.LennardJones") > 0)
self.assert_(s.find("DEBUG") > 0)
self.assert_(s.find("TRACE") < 0)
f.close()
def testEnergy(self):
lj = LennardJones(epsilon=2.0, sigma=2.0)
# root
self.assertAlmostEqual(lj.computeEnergy(2.0), 0.0)
self.assertAlmostEqual(lj.computeEnergy(2.0, 0.0, 0.0), 0.0)
# minimum
self.assertAlmostEqual(lj.computeEnergy(2.0 * 2.0**(1.0 / 6.0)), -2.0)
self.assertAlmostEqual(
lj.computeEnergy(0.0, 2.0 * 2.0**(1.0 / 6.0), 0.0), -2.0)
def testDefaults(self):
lj = LennardJones()
self.assertEqual(lj.epsilon, 1.0)
self.assertEqual(lj.sigma, 1.0)
self.assertEqual(lj.cutoff, infinity)
self.assertEqual(lj.shift, 0.0)
