Hi,

I'm trying to set up arrow with pyscf, and am getting an error when trying to run the example below:

'''
Use Cornell SHCI program as the active space solver for CASSCF
'''

from pyscf import gto, scf, mcscf, cornell_shci

b = 1.2
mol = gto.M(
atom = 'H 0 0 0; H 0 0 %f'%b,
basis = 'cc-pvdz',
verbose = 4,
symmetry = 1
)
mf = scf.RHF(mol).run()

mc = mcscf.CASCI(mf, 4, 2)
mc.fcisolver = cornell_shci.SHCI(mol)
mc.kernel()

#Error:

ERROR: mpirun -n 1 /mnt/beegfs/home/friesner/jlw2245/shci/shci

CalledProcessError Traceback (most recent call last)
~/.local/lib/python3.7/site-packages/pyscf/cornell_shci/shci.py in execute_shci(shciobj)
446 with open(output, 'w') as f:
--> 447 check_call(cmd.split(), cwd=shciobj.runtimedir, stdout=f, stderr=f)
448 except CalledProcessError as err:

/cm/local/apps/python3/lib/python3.7/subprocess.py in check_call(*popenargs, **kwargs)
362 cmd = popenargs[0]
--> 363 raise CalledProcessError(retcode, cmd)
364 return 0

CalledProcessError: Command '['mpirun', '-n', '1', '/mnt/beegfs/home/friesner/jlw2245/shci/shci']' returned non-zero exit status 139.

During handling of the above exception, another exception occurred:

TypeError Traceback (most recent call last)
in
----> 1 mc.kernel()

~/.local/lib/python3.7/site-packages/pyscf/mcscf/casci_symm.py in kernel(self, mo_coeff, ci0, verbose)
55 # Initialize/overwrite self.fcisolver.orbsym and self.fcisolver.wfnsym
56 mo_coeff = self.mo_coeff = label_symmetry_(self, mo_coeff, ci0)
---> 57 return casci.CASCI.kernel(self, mo_coeff, ci0, verbose)
58
59 def _eig(self, mat, b0, b1, orbsym=None):

~/.local/lib/python3.7/site-packages/pyscf/mcscf/casci.py in kernel(self, mo_coeff, ci0, verbose)
944
945 self.e_tot, self.e_cas, self.ci =
--> 946 kernel(self, mo_coeff, ci0=ci0, verbose=log)
947
948 if self.canonicalization:

~/.local/lib/python3.7/site-packages/pyscf/mcscf/casci.py in kernel(casci, mo_coeff, ci0, verbose, envs)
578 ci0=ci0, verbose=log,
579 max_memory=max_memory,
--> 580 ecore=energy_core)
581
582 t1 = log.timer('FCI solver', *t1)

~/.local/lib/python3.7/site-packages/pyscf/cornell_shci/shci.py in kernel(self, h1e, eri, norb, nelec, ci0, ecore, restart, **kwargs)
278 raise NotImplementedError
279
--> 280 execute_shci(self)
281 if self.verbose >= logger.DEBUG1:
282 with open(os.path.join(self.runtimedir, self.outputfile), 'r') as f:

~/.local/lib/python3.7/site-packages/pyscf/cornell_shci/shci.py in execute_shci(shciobj)
448 except CalledProcessError as err:
449 logger.error(shciobj, cmd)
--> 450 shciobj.stdout.write(check_output(['tail', '-100', output]))
451 raise err
452 return output

Is there anything more I need to do to get this working?

I was also wondering how exactly one would extract the CI coefficients and corresponding determinant structure - when using cornell_shci.SHCISCF to set up a CASSCF calculation it runs ok, but the .ci object is a float rather than an array of CI coefficients as I expected.

Thanks!
Jack

This link at the end of readme no longer works:
http://pyscf.org/pyscf/install.html#extension-modules

The current parser extracts the first value of the energy, rather than the extrapolated one (if extrapolation is performed).
To get the extrapolated energy, extrapolate.py must be run after SHCI and the parser would have to be modified, e.g.:

def read_energy(shciobj, state_id=None):
    result = get_result(shciobj)

    if state_id is None:
        state_id = '%.2e' % (min(shciobj.config['eps_vars']))

    if 'energy_total' in result:
        if 'extrapolated' in result['energy_total']:
            e= result['energy_total']['extrapolated']['value']
        else:
            e = list(list(result["energy_total"].values())[0].values())[0]["value"]
    else:
        e = result['energy_var'][state_id]
    return e