qiskit.chemistry.components.variational_forms.CHC
class CHC(num_qubits=None, reps=1, ladder=False, excitations=None, entanglement='full', initial_state=None)
This trial wavefunction is the Compact Heuristic for Chemistry.
The trial wavefunction is as defined in Ollitrault Pauline J., Chemical science 11 (2020): 6842-6855. It aims at approximating the UCC Ansatz for a lower CNOT count.
It is not particle number conserving and the accuracy of the approximation decreases with the number of excitations.
Parameters
- num_qubits (
Optional[int]) – number of qubits - reps (
int) – number of replica of basic module - ladder (
bool) – use ladder of CNOTs between to indices in the entangling block - excitations (
Optional[List[List[int]]]) – indices corresponding to the excitations to include in the circuit - entanglement (
Union[str,List[int]]) – physical connections between the qubits - initial_state (
Union[QuantumCircuit,InitialState,None]) – an initial state to prepend to the variational form
__init__
__init__(num_qubits=None, reps=1, ladder=False, excitations=None, entanglement='full', initial_state=None)
Parameters
- num_qubits (
Optional[int]) – number of qubits - reps (
int) – number of replica of basic module - ladder (
bool) – use ladder of CNOTs between to indices in the entangling block - excitations (
Optional[List[List[int]]]) – indices corresponding to the excitations to include in the circuit - entanglement (
Union[str,List[int]]) – physical connections between the qubits - initial_state (
Union[QuantumCircuit,InitialState,None]) – an initial state to prepend to the variational form
Methods
__init__([num_qubits, reps, ladder, …]) | type num_qubitsOptional[int] |
construct_circuit(parameters[, q]) | Construct the variational form, given its parameters. |
get_entangler_map(map_type, num_qubits[, offset]) | returns entangler map |
validate_entangler_map(entangler_map, num_qubits) | validate entangler map |
Attributes
num_parameters | Number of parameters of the variational form. |
num_qubits | Number of qubits of the variational form. |
parameter_bounds | Parameter bounds. |
preferred_init_points | Return preferred init points. |
setting | |
support_parameterized_circuit | Whether or not the sub-class support parameterized circuit. |
construct_circuit
construct_circuit(parameters, q=None)
Construct the variational form, given its parameters.
Parameters
- parameters (
Union[ndarray,List[Parameter],ParameterVector]) – circuit parameters - q (
Optional[QuantumRegister]) – Quantum Register for the circuit.
Returns
a quantum circuit with given parameters
Return type
Raises
- ValueError – the number of parameters is incorrect.
- ValueError – if num_qubits has not been set and is still None
- ValueError – only supports single and double excitations at the moment.
get_entangler_map
static get_entangler_map(map_type, num_qubits, offset=0)
returns entangler map
num_parameters
Number of parameters of the variational form.
Returns
An integer indicating the number of parameters.
Return type
int
num_qubits
Number of qubits of the variational form.
Returns
An integer indicating the number of qubits.
Return type
int
parameter_bounds
Parameter bounds.
Returns
A list of pairs indicating the bounds, as (lower, upper). None indicates an unbounded parameter in the corresponding direction. If None is returned, problem is fully unbounded.
Return type
list
preferred_init_points
Return preferred init points.
If an initial state is provided then the variational form may provide back this set of parameters which when used on the variational form should result in the overall state being that defined by the initial state
setting
support_parameterized_circuit
Whether or not the sub-class support parameterized circuit.
Returns
indicate the sub-class support parameterized circuit
Return type
boolean
validate_entangler_map
static validate_entangler_map(entangler_map, num_qubits)
validate entangler map