A new LibXC interface and new MC-DCFT code

MANIFEST.in

@@ -9,6 +9,9 @@ include pyscf/lib/*.so
 # macos dynamic libraries
 include pyscf/lib/*.dylib
 
+# include libxc_cffi
+include pyscf/dft2/libxc_cffi.*
+
 # source code
 prune pyscf/lib/build
 recursive-include pyscf/lib *.c *.h CMakeLists.txt

examples/mcdcft/01_h2_potential_curve.py

@@ -1,21 +1,20 @@
-import pyscf
-from pyscf import scf, gto, mcscf, lib
+from pyscf import scf, gto, lib, mcscf, mcdcft
 import numpy as np
-#from pyscf.fci import csf_solver
-from pyscf.mcdcft import mcdcft
 
 '''
 This input file performs a potential energy scan of H2 using cBLYP (density
 coherence functional without reparameterization).
 '''
 
+xc_preset = dict(args=dict(f=mcdcft.dcfnal.f_v1, negative_rho=True))
+
 def run(r, chkfile=None, mo_coeff=None):
-    r /= 2
-    mol = gto.M(atom=f'H  0 0 {r}; H 0 0 -{r}', basis='cc-pvtz', 
+    r *= 0.5
+    mol = gto.M(atom=f'H  0 0 {r}; H 0 0 -{r}', basis='cc-pvtz',
           symmetry=False, verbose=3, unit='angstrom')
     mf = scf.RHF(mol)
     mf.kernel()
-    mc = mcdcft.CASSCF(mf, 'BLYP', 2, 2, ot_name='cBLYP', 
+    mc = mcdcft.CASSCF(mf, 'BLYP', 2, 2, xc_preset=xc_preset,
                        grids_level=6)
     #mc.fcisolver = csf_solver(mol, smult=1)
     mc.fix_spin_(ss=0)
@@ -39,7 +38,6 @@ def scan():
         if mc and mc.converged:
             mo_coeff = mc.mo_coeff
             e_tot = mc.e_tot
-            mc.dump_mcdcft_chk(chkfile)
         else:
             print(f"Warning: bond distance {r:02.2f} not converged")
 

examples/mcdcft/02_h2_potential_curve_restart.py

@@ -1,34 +1,32 @@
-import pyscf
-from pyscf import scf, gto, mcscf, lib
+from pyscf import scf, gto, mcscf, lib, mcdcft
 import numpy as np
-#from pyscf.fci import csf_solver
-from pyscf.mcdcft import mcdcft
 
 '''
-This input file performs a potential energy scan of H2 using cBLYP-2 (density coherence functional with reparameterization). It will read the checkpoint files generated by example 01.
+This input file performs a potential energy scan of H2 using cBLYP-2 (density coherence functional
+with reparameterization). It will read the checkpoint files generated by example 01.
 '''
 
+xc_preset = dict(args=dict(f=mcdcft.dcfnal.f_v1, negative_rho=True), display_name='cBLYP-2')
+
 def run(chkfile):
     mol = lib.chkfile.load_mol(chkfile)
     mol.verbose = 3
-    mf = scf.RHF(mol)
-    mc = mcdcft.CASSCF(mf, None, 2, 2, grids_level=6)
+    mc = mcdcft.DCFT_base(mol, grids_level=6)
     mc.load_mcdcft_chk(chkfile)
-    mc.recalculate_with_xc('0.92 * B88 , 1.59 * LYP', 
-                            ot_name='cBLYP-2', dump_chk=chkfile)
+    mc.recalculate_with_xc('0.92 * B88 , 1.59 * LYP',
+                            xc_preset=xc_preset, dump_chk=chkfile)
     return mc
 
 
 def scan():
-    mo_coeff = None
     method = 'MC-DCFT'
 
     rrange = np.arange(0.5, 6.1, 0.1)
 
     for r in rrange:
         chkfile = f'{method}_{r:02.2f}.chk'
-        mc = run(chkfile)
-        
+        run(chkfile)
+
 
 if __name__ == '__main__':
     lib.num_threads(2)

examples/mcdcft/03_DC24_single_point.py

@@ -0,0 +1,14 @@
+from pyscf import scf, gto, mcdcft
+
+'''
+This input file performs a single point energy calculation of H2 with DC24.
+'''
+
+mol = gto.M(atom='H 0 0 0; H 0 0 0.74', basis='def2-tzvp',
+      symmetry=False, verbose=3, unit='angstrom')
+mf = scf.RHF(mol)
+mf.kernel()
+mc = mcdcft.CASSCF(mf, 'DC24', 2, 2, grids_level=(99, 590))
+mc.chkfile = 'H2_DC24.chk'
+mc.kernel()
+

pyproject.toml

@@ -1,2 +1,2 @@
 [build-system]
-requires = ["setuptools", "wheel", "cmake", "pyscf", "numpy"]
+requires = ["setuptools", "wheel", "cmake", "pyscf", "numpy", "cffi"]

pyscf/dft2/__init__.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python
+# Copyright 2014-2022 The PySCF Developers. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+from pyscf.dft2 import libxc