def calculate_ground_state(hamiltonian,
initial_wf=None,
min_lanczos_iterations=3,
too_many_iterations=1000,
precision=0.000001):
"""Calculates the ground state energy and wavefunction.
Parameters
----------
hamiltonian : a CompositeOperator
The hamiltonian you want to diagonalize.
initial_wf : a Wavefunction, optional
The wavefunction that will be used as seed. If None, a random one
if used.
min_lanczos_iterations : an int, optional.
The number of iterations before starting the diagonalizations.
too_many_iterations : a int, optional.
The maximum number of iterations allowed.
precision : a double, optional.
The accepted precision to which the ground state energy is
considered not improving.
Returns
-------
gs_energy : a double.
The ground state energy.
gs_wf : a Wavefunction.
The ground state wavefunction (normalized.)
"""
if initial_wf is None:
initial_wf = Wavefunction(hamiltonian.left_dim, hamiltonian.right_dim)
initial_wf.randomize()
gs_energy, d, e, saved_lanczos_vectors = (calculate_ground_state_energy(
hamiltonian, initial_wf, min_lanczos_iterations, too_many_iterations,
precision))
gs_wf = calculate_ground_state_wf(d, e, saved_lanczos_vectors)
return gs_energy, gs_wf
def calculate_ground_state(hamiltonian, initial_wf = None,
min_lanczos_iterations = 3,
too_many_iterations = 1000,
precision = 0.000001):
"""Calculates the ground state energy and wavefunction.
Parameters
----------
hamiltonian : a CompositeOperator
The hamiltonian you want to diagonalize.
initial_wf : a Wavefunction, optional
The wavefunction that will be used as seed. If None, a random one
if used.
min_lanczos_iterations : an int, optional.
The number of iterations before starting the diagonalizations.
too_many_iterations : a int, optional.
The maximum number of iterations allowed.
precision : a double, optional.
The accepted precision to which the ground state energy is
considered not improving.
Returns
-------
gs_energy : a double.
The ground state energy.
gs_wf : a Wavefunction.
The ground state wavefunction (normalized.)
"""
if initial_wf is None:
initial_wf = Wavefunction(hamiltonian.left_dim,
hamiltonian.right_dim)
initial_wf.randomize()
gs_energy, d, e, saved_lanczos_vectors = (
calculate_ground_state_energy(hamiltonian, initial_wf, min_lanczos_iterations,
too_many_iterations, precision) )
gs_wf = calculate_ground_state_wf(d, e, saved_lanczos_vectors)
return gs_energy, gs_wf
