Read in CISD wave functions

[lkwagner]

Currently there is not a way to read in CISD wave functions. Here is an example piece of code we'd like to be able to execute:

import numpy
from pyscf.pbc import gto, dft
from pyscf.pbc.dft import multigrid
import pyscf.pbc
import pyscf.pbc.ci

cell = gto.M(
    verbose = 4,
    a = numpy.eye(3)*3.5668,
    atom = '''C     0.      0.      0.    
              C     0.8917  0.8917  0.8917
              C     1.7834  1.7834  0.    
              C     2.6751  2.6751  0.8917
              C     1.7834  0.      1.7834
              C     2.6751  0.8917  2.6751
              C     0.      1.7834  1.7834
              C     0.8917  2.6751  2.6751''',
    #basis = 'sto3g',
    #basis = 'ccpvdz',
    basis = 'gth-szv',
    pseudo = 'gth-pade',
    max_memory=6000,
    #ecp='ccecp',
    #basis='ccecpccpvdz'
)
cell.exp_to_discard=0.2
cell.build()

mf = dft.RKS(cell)
mf.xc = 'lda,vwn'
mf = multigrid.multigrid(mf)
mf.chkfile = "graphene_multigrid.chk"
mf.kernel()


mf_hf = pyscf.pbc.scf.RHF(cell)
mf_hf.__dict__.update(mf.__dict__)


myci = pyscf.pbc.ci.CISD(mf_hf)
myci.nroots=10
myci.run()
print(dir(myci))
print(myci.ci)

[lkwagner]

Not a priority at this time.