def __init__(self, ham_filename, **kwargs):
ham_opts, param_opts, misc_opts = self.set_defaults(kwargs)
# Read in the Hamiltonian integrals from file
self.sys_ham = det_ops.HAM(filename=ham_filename, **ham_opts)
ref_energy = self.sys_ham.slater_condon(self.sys_ham.ref_det,
self.sys_ham.ref_det, None,
None)
# Setup simulation parameters. See system.py for details.
self.sim_params = system.PARAMS(**param_opts)
# Setup a statistics object, which accumulates various run-time variables.
# See system.py for more details.
self.sim_stats = system.STATS(self.sim_params,
filename='fciqmc_stats',
ref_energy=ref_energy)
# Set up walker object as a dictionary.
# Label determinants by the string representation of the list of occupied orbitals
self.walkers = {repr(self.sys_ham.ref_det): self.sim_params.nwalk_init}
self.sim_stats.nw = self.sim_params.nwalk_init
e, v = np.linalg.eigh(full_h)
print('Ground state energy of full hamiltonian is {}'.format(e[0]))
# Find the reference energy from the first element of the Hamiltonian.
# Define h_sim, which is where the reference energy has been removed from the diagonal of the hamiltonian
ref_energy = full_h[0,0]
h_sim = full_h - np.eye(full_h.shape[0])*ref_energy
print('Removing reference energy from simulated hamiltonian')
# Setup simulation parameters. See system.py for details.
sim_params = system.PARAMS(totwalkers=2000, initwalkers=10, init_shift=0.0,
shift_damp=0.1, timestep=1.e-2, det_thresh=0.25, eqm_iters=250,
max_iter=15000, stats_cycle=10, seed=7)
# Setup a statistics object, which accumulates various run-time variables.
# See system.py for more details.
sim_stats = system.STATS(sim_params, filename='fciqmc_stats', ref_energy=ref_energy)
# Set up walker object as a dictionary.
# Initially, label determinants by their index in the hamiltonian array.
walkers = {0: sim_params.nwalk_init}
sim_stats.nw = sim_params.nwalk_init
for sim_stats.iter_curr in range(sim_params.max_iter):
spawned_walkers = {} # Dictionary to hold the spawned walkers of each iteration
sim_stats.nw = 0.0 # Recompute number of walkers each iteration
sim_stats.ref_weight = 0.0
sim_stats.nocc_dets = 0
# Iterate over occupied (not all) determinants (keys) in the dictionary
# Note that this is python3 format