def compute_energy(self):
Hcore, G, Da, Db, X = self.Hcore, self.G, self.Da, self.Db, self.X
for i in range(get_maxiter()):
va = np.einsum("mnrs,ns->mr", G, Da) - np.einsum(
"mnsr,ns->mr", G, Da) + np.einsum("mnrs,ns->mr", G, Db)
vb = np.einsum("mnrs,ns->mr", G, Db) - np.einsum(
"mnsr,ns->mr", G, Db) + np.einsum("mnrs,ns->mr", G, Da)
Fa = Hcore + va
Fb = Hcore + vb
tFa = X.dot(Fa.dot(X))
tFb = X.dot(Fb.dot(X))
ea, tCa = la.eigh(tFa)
eb, tCb = la.eigh(tFb)
Ca = X.dot(tCa)
Cb = X.dot(tCb)
oCa = Ca[:, :self.Na]
oCb = Cb[:, :self.Nb]
Da = oCa.dot(oCa.T)
Db = oCb.dot(oCb.T)
E0 = self.E
E = np.trace((Hcore + 0.5 * va).dot(Da)) + np.trace(
(Hcore + 0.5 * vb).dot(Db)) + self.Vnu
dE = np.fabs(E - E0)
if dE < self.conv: break
print("UHF {:>4} {: >21.13} {: >21.13}".format(i, E, dE))
## save
self.Da, self.Db, self.E = Da, Db, E
return self.E
