UnivariatePiecewiseLinearObjective

class UnivariatePiecewiseLinearObjective(num_state_qubits, min_state_value, max_state_value, breakpoints, slopes, offsets, f_min, f_max, c_approx, i_state=None, i_objective=None)

Bases: qiskit.aqua.utils.circuit_factory.CircuitFactory

Univariate Piecewise Linear Objective Function.

This objective function applies controlled Y-rotation to the target qubit, where the control qubits represent integer value, and rotation approximates a piecewise linear function of the amplitude f:

\[|x\rangle |0\rangle \mapsto |x\rangle (\sqrt(1 - f(x))|0\rangle + sqrt(f(x))|1\rangle )\]

Parameters

• num_state_qubits (int) – number of qubits to represent the state

• min_state_value (float) – lower bound of values to be represented by state qubits

• max_state_value (float) – upper bound of values to be represented by state qubits

• breakpoints (Union[List[float], ndarray]) – breakpoints of piecewise linear function

• slopes (Union[List[float], ndarray]) – slopes of linear segments

• offsets (Union[List[float], ndarray]) – offset of linear segments

• f_min (float) – minimal value of resulting function (required for normalization of amplitude)

• f_max (float) – maximal value of resulting function (required for normalization of amplitude)

• c_approx (float) – approximating factor (linear segments are approximated by contracting rotation around pi/4, where sin^2() is locally linear)

• i_state (Optional[List[int]]) – indices of qubits that represent the state

• i_objective (Optional[int]) – index of target qubit to apply the rotation to

Methods

build
build_controlled	Adds corresponding controlled sub-circuit to given circuit
build_controlled_inverse	Adds controlled inverse of corresponding sub-circuit to given circuit
build_controlled_inverse_power	Adds controlled, inverse, power of corresponding circuit.
build_controlled_power	Adds controlled power of corresponding circuit.
build_inverse	Adds inverse of corresponding sub-circuit to given circuit
build_inverse_power	Adds inverse power of corresponding circuit.
build_power	Adds power of corresponding circuit.
get_num_qubits	returns number of qubits
get_num_qubits_controlled	returns number of qubits controlled
required_ancillas	requires ancillas
required_ancillas_controlled	returns required ancillas controlled
value_to_estimation	value to estimation

Attributes

num_target_qubits

Returns the number of target qubits