Add callback solver example using dyson for EWDMET

examples/ewdmet/65-callback-solver-dyson.py

@@ -0,0 +1,67 @@
+import numpy as np
+import pyscf
+import pyscf.gto
+import pyscf.scf
+import pyscf.fci
+import vayesta
+import vayesta.ewf
+from vayesta.misc.molecules import ring
+from dyson import FCI
+
+
+# User defined FCI solver - takes pyscf mf as input and returns RDMs
+# The mf argment contains the hamiltonain in the orthonormal cluster basis
+# Pyscf or other solvers may be used to solve the cluster problem and may return RDMs, CIID amplitudes or CCSD amplitudes
+def solver(mf):
+    fci_1h = FCI["1h"](mf)
+    fci_1p = FCI["1p"](mf)
+
+    # Use MBLGF
+    nmom_max = 4
+    th = fci_1h.build_gf_moments(nmom_max)
+    tp = fci_1p.build_gf_moments(nmom_max)
+
+    norb = mf.mo_coeff.shape[-1]
+    nelec = mf.mol.nelec
+    civec= fci_1h.c_ci
+    dm1, dm2 = pyscf.fci.direct_spin0.make_rdm12(civec, norb, nelec)
+    results = dict(dm1=dm1, dm2=dm2, hole_moments=th, particle_moments=tp, converged=True)
+    return results
+
+natom = 10
+mol = pyscf.gto.Mole()
+mol.atom = ring("H", natom, 1.5)
+mol.basis = "sto-3g"
+mol.output = "pyscf.out"
+mol.verbose = 5
+mol.symmetry = True
+mol.build()
+
+# Hartree-Fock
+mf = pyscf.scf.RHF(mol)
+mf.kernel()
+
+# Vayesta options
+use_sym = True
+nfrag = 1 
+bath_opts = dict(bathtype="ewdmet", order=1, max_order=1)   
+
+# Run vayesta with user defined solver
+emb = vayesta.ewf.EWF(mf, solver="CALLBACK",  energy_functional='dmet', bath_options=bath_opts, solver_options=dict(callback=solver))
+emb.qpewdmet_scmf(proj=2, maxiter=10)
+# Set up fragments
+with emb.iao_fragmentation() as f:
+    if use_sym:
+        # Add rotational symmetry
+        with f.rotational_symmetry(order=natom//nfrag, axis=[0, 0, 1]):
+            f.add_atomic_fragment(range(nfrag))
+    else:
+        # Add all atoms as separate fragments 
+        f.add_all_atomic_fragments()
+emb.kernel()
+
+print("Hartree-Fock energy          : %s"%mf.e_tot)
+print("DMET energy                  : %s"%emb.get_dmet_energy(part_cumulant=False, approx_cumulant=False))
+print("DMET energy   (part-cumulant): %s"%emb.get_dmet_energy(part_cumulant=True, approx_cumulant=False))
+print("DMET energy (approx-cumulant): %s"%emb.get_dmet_energy(part_cumulant=True, approx_cumulant=True))
+

examples/ewf/molecules/65-callback-solver.py

@@ -8,6 +8,8 @@
 from vayesta.misc.molecules import ring
 
 # User defined FCI solver - takes pyscf mf as input and returns RDMs
+# The mf argment contains the hamiltonain in the orthonormal cluster basis
+# Pyscf or other solvers may be used to solve the cluster problem and may return RDMs, CIID amplitudes or CCSD amplitudes
 def solver(mf):
     h1e = mf.get_hcore()
     h2e = mf._eri

vayesta/ewf/ewf.py

@@ -310,11 +310,17 @@ def get_e_corr(self, functional=None, **kwargs):
             self.log.warning("functional='projected' is deprecated; use functional='wf' instead.")
             functional = "wf"
         if functional == "wf":
+            # CCSD projected energy expression 
             return self.get_wf_corr_energy(**kwargs)
         if functional == "dm-t2only":
+            # Builds density matrices from projected amplitudes
             return self.get_dm_corr_energy(t_as_lambda=True, **kwargs)
         if functional == "dm":
+            # Builds density matrices from projected amplitudes
             return self.get_dm_corr_energy(**kwargs)
+        if functional == 'dmet':
+            # Uses projected denisty matrices
+            return self.get_dmet_energy(**kwargs)
         raise ValueError("Unknown energy functional: '%s'" % functional)
 
     @mpi.with_allreduce()