Add examples for DFT+U

CHANGELOG

@@ -328,6 +328,7 @@ PySCF 1.7.6 (2021-03-28)
   - Auxiliary second-order Green's function perturbation theory (AGF2)
   - Smearing for molecules
   - Visscher small component correction approximation for DHF
+  - DFT+U
 * Improved
   - Threading safety in Mole temporary context
   - Basis parser to support arithmetic expressions in basis data

examples/pbc/22-dft+u.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+
+'''
+DFT+U with kpoint sampling
+'''
+
+from pyscf.pbc import gto, dft
+cell = gto.Cell()
+cell.unit = 'A'
+cell.atom = 'C 0.,  0.,  0.; C 0.8917,  0.8917,  0.8917'
+cell.a = '''0.      1.7834  1.7834
+            1.7834  0.      1.7834
+            1.7834  1.7834  0.    '''
+
+cell.basis = 'gth-dzvp'
+cell.pseudo = 'gth-pade'
+cell.verbose = 4
+cell.build()
+
+kmesh = [2, 2, 2]
+kpts = cell.make_kpts(kmesh)
+# Add U term to the 2p orbital of the second Carbon atom
+U_idx = ['1 C 2p']
+U_val = [5.0]
+mf = dft.KRKSpU(cell, kpts, U_idx=U_idx, U_val=U_val, minao_ref='gth-szv')
+print(mf.U_idx)
+print(mf.U_val)
+mf.run()
+
+# When space group symmetry in k-point samples is enabled, the symmetry adapted
+# DFT+U method will be invoked automatically.
+kpts = cell.make_kpts(
+    kmesh, wrap_around=True, space_group_symmetry=True, time_reversal_symmetry=True)
+# Add U term to 2s and 2p orbitals
+U_idx = ['2p', '2s']
+U_val = [5.0, 2.0]
+mf = dft.KUKSpU(cell, kpts, U_idx=U_idx, U_val=U_val, minao_ref='gth-szv')
+print(mf.U_idx)
+print(mf.U_val)
+mf.run()

pyscf/pbc/dft/krkspu.py

@@ -280,32 +280,3 @@ def __init__(self, cell, kpts=np.zeros((1,3)), xc='LDA,VWN',
 
     def nuc_grad_method(self):
         raise NotImplementedError
-
-if __name__ == '__main__':
-    from pyscf.pbc import gto
-    np.set_printoptions(3, linewidth=1000, suppress=True)
-    cell = gto.Cell()
-    cell.unit = 'A'
-    cell.atom = 'C 0.,  0.,  0.; C 0.8917,  0.8917,  0.8917'
-    cell.a = '''0.      1.7834  1.7834
-                1.7834  0.      1.7834
-                1.7834  1.7834  0.    '''
-
-    cell.basis = 'gth-dzvp'
-    cell.pseudo = 'gth-pade'
-    cell.verbose = 7
-    cell.build()
-    kmesh = [2, 2, 2]
-    kpts = cell.make_kpts(kmesh, wrap_around=True)
-    #U_idx = ["2p", "2s"]
-    #U_val = [5.0, 2.0]
-    U_idx = ["1 C 2p"]
-    U_val = [5.0]
-
-    mf = KRKSpU(cell, kpts, U_idx=U_idx, U_val=U_val, C_ao_lo='minao',
-                minao_ref='gth-szv')
-    mf.conv_tol = 1e-10
-    print (mf.U_idx)
-    print (mf.U_val)
-    print (mf.C_ao_lo.shape)
-    print (mf.kernel())

pyscf/pbc/dft/krkspu_ksymm.py

@@ -38,33 +38,3 @@ def __init__(self, cell, kpts=libkpts.KPoints(), xc='LDA,VWN',
                                minao_ref=minao_ref, **kwargs)
 
 KRKSpU = KsymAdaptedKRKSpU
-
-if __name__ == '__main__':
-    from pyscf.pbc import gto
-    np.set_printoptions(3, linewidth=1000, suppress=True)
-    cell = gto.Cell()
-    cell.unit = 'A'
-    cell.atom = 'C 0.,  0.,  0.; C 0.8917,  0.8917,  0.8917'
-    cell.a = '''0.      1.7834  1.7834
-                1.7834  0.      1.7834
-                1.7834  1.7834  0.    '''
-
-    cell.basis = 'gth-dzvp'
-    cell.pseudo = 'gth-pade'
-    cell.verbose = 7
-    cell.build()
-    kmesh = [2, 2, 2]
-    kpts = cell.make_kpts(kmesh, wrap_around=True,
-                          space_group_symmetry=True, time_reversal_symmetry=True)
-    #U_idx = ["2p", "2s"]
-    #U_val = [5.0, 2.0]
-    U_idx = ["1 C 2p"]
-    U_val = [5.0]
-
-    mf = KRKSpU(cell, kpts, U_idx=U_idx, U_val=U_val, C_ao_lo='minao',
-                minao_ref='gth-szv')
-    mf.conv_tol = 1e-10
-    print (mf.U_idx)
-    print (mf.U_val)
-    print (mf.C_ao_lo.shape)
-    print (mf.kernel())

pyscf/pbc/dft/kukspu.py

@@ -172,30 +172,3 @@ def __init__(self, cell, kpts=np.zeros((1,3)), xc='LDA,VWN',
 
     def nuc_grad_method(self):
         raise NotImplementedError
-
-if __name__ == '__main__':
-    from pyscf.pbc import gto
-    cell = gto.Cell()
-    cell.unit = 'A'
-    cell.atom = 'C 0.,  0.,  0.; C 0.8917,  0.8917,  0.8917'
-    cell.a = '''0.      1.7834  1.7834
-                1.7834  0.      1.7834
-                1.7834  1.7834  0.    '''
-
-    cell.basis = 'gth-dzvp'
-    cell.pseudo = 'gth-pade'
-    cell.verbose = 7
-    cell.build()
-    kmesh = [2, 2, 2]
-    kpts = cell.make_kpts(kmesh, wrap_around=True)
-    #U_idx = ["2p", "2s"]
-    #U_val = [5.0, 2.0]
-    U_idx = ["1 C 2p"]
-    U_val = [5.0]
-
-    mf = KUKSpU(cell, kpts, U_idx=U_idx, U_val=U_val, minao_ref='gth-szv')
-    mf.conv_tol = 1e-10
-    print (mf.U_idx)
-    print (mf.U_val)
-    print (mf.C_ao_lo.shape)
-    print (mf.kernel())

pyscf/pbc/dft/kukspu_ksymm.py

@@ -38,33 +38,3 @@ def __init__(self, cell, kpts=libkpts.KPoints(), xc='LDA,VWN',
                                minao_ref=minao_ref, **kwargs)
 
 KUKSpU = KsymAdaptedKUKSpU
-
-if __name__ == '__main__':
-    from pyscf.pbc import gto
-    np.set_printoptions(3, linewidth=1000, suppress=True)
-    cell = gto.Cell()
-    cell.unit = 'A'
-    cell.atom = 'C 0.,  0.,  0.; C 0.8917,  0.8917,  0.8917'
-    cell.a = '''0.      1.7834  1.7834
-                1.7834  0.      1.7834
-                1.7834  1.7834  0.    '''
-
-    cell.basis = 'gth-dzvp'
-    cell.pseudo = 'gth-pade'
-    cell.verbose = 7
-    cell.build()
-    kmesh = [2, 2, 2]
-    kpts = cell.make_kpts(kmesh, wrap_around=True,
-                          space_group_symmetry=True, time_reversal_symmetry=True)
-    #U_idx = ["2p", "2s"]
-    #U_val = [5.0, 2.0]
-    U_idx = ["1 C 2p"]
-    U_val = [5.0]
-
-    mf = KUKSpU(cell, kpts, U_idx=U_idx, U_val=U_val, C_ao_lo='minao',
-                minao_ref='gth-szv')
-    mf.conv_tol = 1e-10
-    print (mf.U_idx)
-    print (mf.U_val)
-    print (mf.C_ao_lo.shape)
-    print (mf.kernel())