def calculate_deriv_gto(gto1, gto2, gto3, gto4, coord):
# build integrator object
integrator = PyQInt()
# distance
diff = 0.00001
p = np.zeros(3)
p[coord] = diff
gto1_new1 = gto(gto1.c, gto1.p - 0.5 * p, gto1.alpha, gto1.l, gto1.m,
gto1.n)
gto1_new2 = gto(gto1.c, gto1.p + 0.5 * p, gto1.alpha, gto1.l, gto1.m,
gto1.n)
# build hydrogen molecule
left = integrator.repulsion_gto(gto1_new1, gto2, gto3, gto4)
right = integrator.repulsion_gto(gto1_new2, gto2, gto3, gto4)
return (right - left) / diff
def test_gto_repulsion(self):
"""
Test two-electron integrals for primitive GTOs
(ij|kl) = <gto_i gto_j | r_ij | gto_k gto_l>
"""
# construct integrator object
integrator = PyQInt()
# test GTO
gto1 = gto(0.154329, [0.0, 0.0, 0.0], 3.425251, 0, 0, 0)
gto2 = gto(0.535328, [0.0, 0.0, 0.0], 0.623914, 0, 0, 0)
gto3 = gto(0.444635, [0.0, 0.0, 0.0], 0.168855, 0, 0, 0)
repulsion = integrator.repulsion_gto(gto1, gto1, gto1, gto1)
result = 2.0883402824401855
np.testing.assert_almost_equal(repulsion, result, 4)