VBERippleCarryAdder¶
- class VBERippleCarryAdder(num_state_qubits, kind='full', name='VBERippleCarryAdder')[source]¶
Bases:
qiskit.circuit.library.arithmetic.adders.adder.Adder
The VBE ripple carry adder [1].
This circuit performs inplace addition of two equally-sized quantum registers. As an example, a classical adder circuit that performs full addition (i.e. including a carry-in bit) on two 2-qubit sized registers is as follows:
┌────────┐ ┌───────────┐┌──────┐ cin_0: ┤0 ├───────────────────────┤0 ├┤0 ├ │ │ │ ││ │ a_0: ┤1 ├───────────────────────┤1 ├┤1 ├ │ │┌────────┐ ┌──────┐│ ││ Sum │ a_1: ┤ ├┤1 ├──■──┤1 ├┤ ├┤ ├ │ ││ │ │ │ ││ ││ │ b_0: ┤2 Carry ├┤ ├──┼──┤ ├┤2 Carry_dg ├┤2 ├ │ ││ │┌─┴─┐│ ││ │└──────┘ b_1: ┤ ├┤2 Carry ├┤ X ├┤2 Sum ├┤ ├──────── │ ││ │└───┘│ ││ │ cout_0: ┤ ├┤3 ├─────┤ ├┤ ├──────── │ ││ │ │ ││ │ helper_0: ┤3 ├┤0 ├─────┤0 ├┤3 ├──────── └────────┘└────────┘ └──────┘└───────────┘
Here Carry and Sum gates correspond to the gates introduced in [1]. Carry_dg correspond to the inverse of the Carry gate. Note that in this implementation the input register qubits are ordered as all qubits from the first input register, followed by all qubits from the second input register. This is different ordering as compared to Figure 2 in [1], which leads to a different drawing of the circuit.
References:
[1] Vedral et al., Quantum Networks for Elementary Arithmetic Operations, 1995. arXiv:quant-ph/9511018
- Parameters
num_state_qubits (
int
) – The size of the register.kind (
str
) – The kind of adder, can be'full'
for a full adder,'half'
for a half adder, or'fixed'
for a fixed-sized adder. A full adder includes both carry-in and carry-out, a half only carry-out, and a fixed-sized adder neither carry-in nor carry-out.name (
str
) – The name of the circuit.
- Raises
ValueError – If
num_state_qubits
is lower than 1.
Attributes
- ancillas¶
Returns a list of ancilla bits in the order that the registers were added.
- Return type
List
[AncillaQubit
]
- calibrations¶
Return calibration dictionary.
- The custom pulse definition of a given gate is of the form
{‘gate_name’: {(qubits, params): schedule}}
- Return type
dict
- clbits¶
Returns a list of classical bits in the order that the registers were added.
- Return type
List
[Clbit
]
- data¶
Return the circuit data (instructions and context).
- Returns
a list-like object containing the tuples for the circuit’s data.
Each tuple is in the format
(instruction, qargs, cargs)
, where instruction is an Instruction (or subclass) object, qargs is a list of Qubit objects, and cargs is a list of Clbit objects.- Return type
QuantumCircuitData
- extension_lib = 'include "qelib1.inc";'¶
- global_phase¶
Return the global phase of the circuit in radians.
- Return type
Union
[ParameterExpression
,float
]
- header = 'OPENQASM 2.0;'¶
- instances = 9¶
- metadata¶
The user provided metadata associated with the circuit
The metadata for the circuit is a user provided
dict
of metadata for the circuit. It will not be used to influence the execution or operation of the circuit, but it is expected to be passed between all transforms of the circuit (ie transpilation) and that providers will associate any circuit metadata with the results it returns from execution of that circuit.- Return type
dict
- num_ancillas¶
Return the number of ancilla qubits.
- Return type
int
- num_clbits¶
Return number of classical bits.
- Return type
int
- num_parameters¶
Convenience function to get the number of parameter objects in the circuit.
- Return type
int
- num_qubits¶
Return number of qubits.
- Return type
int
- num_state_qubits¶
The number of state qubits, i.e. the number of bits in each input register.
- Return type
int
- Returns
The number of state qubits.
- parameters¶
Convenience function to get the parameters defined in the parameter table.
- Return type
ParameterView
- prefix = 'circuit'¶