Updates to examples

examples/00-ccsd.py

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+import numpy as np
+from pyscf import gto, scf
+
+from ebcc import EBCC
+
+mol = gto.Mole()
+mol.atom = "H 0 0 0; F 0 0 1.1"
+mol.basis = "cc-pvdz"
+mol.build()
+
+mf = scf.RHF(mol)
+mf.kernel()
+
+ccsd = EBCC(mf)
+ccsd.kernel()

examples/01-ebccsd.py

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+import numpy as np
+from pyscf import gto, scf
+
+from ebcc import EBCC
+
+np.random.seed(123)
+
+mol = gto.Mole()
+mol.atom = "H 0 0 0; F 0 0 1.1"
+mol.basis = "cc-pvdz"
+mol.build()
+
+mf = scf.RHF(mol)
+mf.kernel()
+
+# Define boson energies and couplings to AO density:
+nbos = 5
+nmo = mf.mo_occ.size
+g = np.random.random((nbos, nmo, nmo)) * 0.03
+omega = np.random.random((nbos,)) * 5.0
+
+#    ,-------- Fermionic ansatz
+#    | ,------ Bosonic excitation amplitudes
+#    | | ,---- Rank of fermions in coupling term
+#    | | | ,-- Rank of bosons in coupling term
+#    v v v v
+# ____ _ _ _
+# CCSD-S-1-1: One-boson amplitudes and one-boson-one-fermion coupling
+ccsd = EBCC(
+    mf,
+    ansatz="CCSD",
+    boson_excitations="S",
+    fermion_coupling_rank=1,
+    boson_coupling_rank=1,
+    omega=omega,
+    g=g,
+)
+ccsd.kernel()
+
+#    ,--------- Fermionic ansatz
+#    |  ,------ Bosonic excitation amplitudes
+#    |  | ,---- Rank of fermions in coupling term
+#    |  | | ,-- Rank of bosons in coupling term
+#    v  v v v
+# ____ __ _ _
+# CCSD-SD-1-1: Two-boson amplitudes and one-boson-one-fermion coupling
+ccsd = EBCC(
+    mf,
+    ansatz="CCSD",
+    boson_excitations="SD",
+    fermion_coupling_rank=1,
+    boson_coupling_rank=1,
+    omega=omega,
+    g=g,
+)
+ccsd.kernel()
+
+#    ,--------- Fermionic ansatz
+#    |  ,------ Bosonic excitation amplitudes
+#    |  | ,---- Rank of fermions in coupling term
+#    |  | | ,-- Rank of bosons in coupling term
+#    v  v v v
+# ____ __ _ _
+# CCSD-SD-1-2: Two-boson amplitudes and two-boson-one-fermion coupling
+ccsd = EBCC(
+    mf,
+    ansatz="CCSD",
+    boson_excitations="SD",
+    fermion_coupling_rank=1,
+    boson_coupling_rank=2,
+    omega=omega,
+    g=g,
+)
+ccsd.kernel()

examples/02-eom_uccsd.py

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+import numpy as np
+from pyscf import gto, scf
+
+from ebcc import UEBCC
+
+mol = gto.Mole()
+mol.atom = "H 0 0 0; F 0 0 1.1"
+mol.basis = "cc-pvdz"
+mol.build()
+
+mf = scf.UHF(mol)
+mf.kernel()
+
+ccsd = UEBCC(mf)
+ccsd.kernel()
+
+eom = ccsd.ip_eom()
+eom.kernel()

examples/03-cc2.py

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+import numpy as np
+from pyscf import gto, scf
+
+from ebcc import EBCC
+
+mol = gto.Mole()
+mol.atom = "H 0 0 0; F 0 0 1.1"
+mol.basis = "cc-pvdz"
+mol.build()
+
+mf = scf.RHF(mol)
+mf.kernel()
+
+ccsd = EBCC(mf, ansatz="CC2")
+ccsd.kernel()
+