325 lines
16 KiB
Plaintext
325 lines
16 KiB
Plaintext
---
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title: CDKMRippleCarryAdder (latest version)
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description: API reference for qiskit.circuit.library.CDKMRippleCarryAdder in the latest version of qiskit
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in_page_toc_min_heading_level: 1
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python_api_type: class
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python_api_name: qiskit.circuit.library.CDKMRippleCarryAdder
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---
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# CDKMRippleCarryAdder
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<Class id="qiskit.circuit.library.CDKMRippleCarryAdder" isDedicatedPage={true} github="https://github.com/Qiskit/qiskit/tree/stable/1.2/qiskit/circuit/library/arithmetic/adders/cdkm_ripple_carry_adder.py#L20-L159" signature="qiskit.circuit.library.CDKMRippleCarryAdder(num_state_qubits, kind='full', name='CDKMRippleCarryAdder')" modifiers="class">
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Bases: `Adder`
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A ripple-carry circuit to perform in-place addition on two qubit registers.
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As an example, a ripple-carry adder circuit that performs addition on two 3-qubit sized registers with a carry-in bit (`kind="full"`) is as follows:
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```python
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┌──────┐ ┌──────┐
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cin_0: ┤2 ├─────────────────────────────────────┤2 ├
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│ │┌──────┐ ┌──────┐│ │
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a_0: ┤0 ├┤2 ├─────────────────────┤2 ├┤0 ├
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│ ││ │┌──────┐ ┌──────┐│ ││ │
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a_1: ┤ MAJ ├┤0 ├┤2 ├─────┤2 ├┤0 ├┤ UMA ├
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│ ││ ││ │ │ ││ ││ │
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a_2: ┤ ├┤ MAJ ├┤0 ├──■──┤0 ├┤ UMA ├┤ ├
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│ ││ ││ │ │ │ ││ ││ │
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b_0: ┤1 ├┤ ├┤ MAJ ├──┼──┤ UMA ├┤ ├┤1 ├
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└──────┘│ ││ │ │ │ ││ │└──────┘
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b_1: ────────┤1 ├┤ ├──┼──┤ ├┤1 ├────────
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└──────┘│ │ │ │ │└──────┘
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b_2: ────────────────┤1 ├──┼──┤1 ├────────────────
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└──────┘┌─┴─┐└──────┘
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cout_0: ────────────────────────┤ X ├────────────────────────
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└───┘
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```
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Here *MAJ* and *UMA* gates correspond to the gates introduced in \[1]. 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.
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Two different kinds of adders are supported. By setting the `kind` argument, you can also choose a half-adder, which doesn’t have a carry-in, and a fixed-sized-adder, which has neither carry-in nor carry-out, and thus acts on fixed register sizes. Unlike the full-adder, these circuits need one additional helper qubit.
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The circuit diagram for the fixed-point adder (`kind="fixed"`) on 3-qubit sized inputs is
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```python
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┌──────┐┌──────┐ ┌──────┐┌──────┐
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a_0: ┤0 ├┤2 ├────────────────┤2 ├┤0 ├
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│ ││ │┌──────┐┌──────┐│ ││ │
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a_1: ┤ ├┤0 ├┤2 ├┤2 ├┤0 ├┤ ├
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│ ││ ││ ││ ││ ││ │
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a_2: ┤ ├┤ MAJ ├┤0 ├┤0 ├┤ UMA ├┤ ├
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│ ││ ││ ││ ││ ││ │
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b_0: ┤1 MAJ ├┤ ├┤ MAJ ├┤ UMA ├┤ ├┤1 UMA ├
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│ ││ ││ ││ ││ ││ │
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b_1: ┤ ├┤1 ├┤ ├┤ ├┤1 ├┤ ├
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│ │└──────┘│ ││ │└──────┘│ │
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b_2: ┤ ├────────┤1 ├┤1 ├────────┤ ├
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│ │ └──────┘└──────┘ │ │
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help_0: ┤2 ├────────────────────────────────┤2 ├
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└──────┘ └──────┘
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```
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It has one less qubit than the full-adder since it doesn’t have the carry-out, but uses a helper qubit instead of the carry-in, so it only has one less qubit, not two.
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**References:**
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\[1] Cuccaro et al., A new quantum ripple-carry addition circuit, 2004. [arXiv:quant-ph/0410184](https://arxiv.org/pdf/quant-ph/0410184.pdf)
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\[2] Vedral et al., Quantum Networks for Elementary Arithmetic Operations, 1995. [arXiv:quant-ph/9511018](https://arxiv.org/pdf/quant-ph/9511018.pdf)
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**Parameters**
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* **num\_state\_qubits** ([*int*](https://docs.python.org/3/library/functions.html#int "(in Python v3.13)")) – The number of qubits in either input register for state $|a\rangle$ or $|b\rangle$. The two input registers must have the same number of qubits.
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* **kind** ([*str*](https://docs.python.org/3/library/stdtypes.html#str "(in Python v3.13)")) – 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.
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* **name** ([*str*](https://docs.python.org/3/library/stdtypes.html#str "(in Python v3.13)")) – The name of the circuit object.
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**Raises**
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[**ValueError**](https://docs.python.org/3/library/exceptions.html#ValueError "(in Python v3.13)") – If `num_state_qubits` is lower than 1.
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## Attributes
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### ancillas
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.ancillas">
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A list of `AncillaQubit`s in the order that they were added. You should not mutate this.
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</Attribute>
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### calibrations
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.calibrations">
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Return calibration dictionary.
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The custom pulse definition of a given gate is of the form `{'gate_name': {(qubits, params): schedule}}`
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</Attribute>
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### clbits
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.clbits">
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A list of `Clbit`s in the order that they were added. You should not mutate this.
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</Attribute>
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### data
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.data">
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The circuit data (instructions and context).
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**Returns**
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a list-like object containing the [`CircuitInstruction`](qiskit.circuit.CircuitInstruction "qiskit.circuit.CircuitInstruction")s for each instruction.
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**Return type**
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QuantumCircuitData
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</Attribute>
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### global\_phase
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.global_phase">
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The global phase of the current circuit scope in radians.
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</Attribute>
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### instances
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.instances" attributeValue="191" />
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### layout
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.layout">
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Return any associated layout information about the circuit
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This attribute contains an optional [`TranspileLayout`](qiskit.transpiler.TranspileLayout "qiskit.transpiler.TranspileLayout") object. This is typically set on the output from [`transpile()`](compiler#qiskit.compiler.transpile "qiskit.compiler.transpile") or [`PassManager.run()`](qiskit.transpiler.PassManager#run "qiskit.transpiler.PassManager.run") to retain information about the permutations caused on the input circuit by transpilation.
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There are two types of permutations caused by the [`transpile()`](compiler#qiskit.compiler.transpile "qiskit.compiler.transpile") function, an initial layout which permutes the qubits based on the selected physical qubits on the [`Target`](qiskit.transpiler.Target "qiskit.transpiler.Target"), and a final layout which is an output permutation caused by [`SwapGate`](qiskit.circuit.library.SwapGate "qiskit.circuit.library.SwapGate")s inserted during routing.
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</Attribute>
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### metadata
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.metadata">
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Arbitrary user-defined metadata for the circuit.
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Qiskit will not examine the content of this mapping, but it will pass it through the transpiler and reattach it to the output, so you can track your own metadata.
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</Attribute>
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### num\_ancillas
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.num_ancillas">
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Return the number of ancilla qubits.
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</Attribute>
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### num\_captured\_vars
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.num_captured_vars">
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The number of real-time classical variables in the circuit marked as captured from an enclosing scope.
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This is the length of the `iter_captured_vars()` iterable. If this is non-zero, [`num_input_vars`](#qiskit.circuit.library.CDKMRippleCarryAdder.num_input_vars "qiskit.circuit.library.CDKMRippleCarryAdder.num_input_vars") must be zero.
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</Attribute>
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### num\_clbits
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.num_clbits">
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Return number of classical bits.
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</Attribute>
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### num\_declared\_vars
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.num_declared_vars">
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The number of real-time classical variables in the circuit that are declared by this circuit scope, excluding inputs or captures.
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This is the length of the `iter_declared_vars()` iterable.
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</Attribute>
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### num\_input\_vars
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.num_input_vars">
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The number of real-time classical variables in the circuit marked as circuit inputs.
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This is the length of the `iter_input_vars()` iterable. If this is non-zero, [`num_captured_vars`](#qiskit.circuit.library.CDKMRippleCarryAdder.num_captured_vars "qiskit.circuit.library.CDKMRippleCarryAdder.num_captured_vars") must be zero.
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</Attribute>
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### num\_parameters
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.num_parameters">
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The number of parameter objects in the circuit.
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</Attribute>
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### num\_qubits
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.num_qubits">
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Return number of qubits.
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</Attribute>
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### num\_state\_qubits
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.num_state_qubits">
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The number of state qubits, i.e. the number of bits in each input register.
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**Returns**
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The number of state qubits.
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</Attribute>
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### num\_vars
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.num_vars">
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The number of real-time classical variables in the circuit.
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This is the length of the `iter_vars()` iterable.
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</Attribute>
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### op\_start\_times
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.op_start_times">
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Return a list of operation start times.
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This attribute is enabled once one of scheduling analysis passes runs on the quantum circuit.
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**Returns**
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List of integers representing instruction start times. The index corresponds to the index of instruction in `QuantumCircuit.data`.
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**Raises**
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[**AttributeError**](https://docs.python.org/3/library/exceptions.html#AttributeError "(in Python v3.13)") – When circuit is not scheduled.
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</Attribute>
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### parameters
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.parameters">
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The parameters defined in the circuit.
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This attribute returns the [`Parameter`](qiskit.circuit.Parameter "qiskit.circuit.Parameter") objects in the circuit sorted alphabetically. Note that parameters instantiated with a [`ParameterVector`](qiskit.circuit.ParameterVector "qiskit.circuit.ParameterVector") are still sorted numerically.
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**Examples**
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The snippet below shows that insertion order of parameters does not matter.
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```python
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>>> from qiskit.circuit import QuantumCircuit, Parameter
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>>> a, b, elephant = Parameter("a"), Parameter("b"), Parameter("elephant")
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>>> circuit = QuantumCircuit(1)
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>>> circuit.rx(b, 0)
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>>> circuit.rz(elephant, 0)
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>>> circuit.ry(a, 0)
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>>> circuit.parameters # sorted alphabetically!
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ParameterView([Parameter(a), Parameter(b), Parameter(elephant)])
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```
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Bear in mind that alphabetical sorting might be unintuitive when it comes to numbers. The literal “10” comes before “2” in strict alphabetical sorting.
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```python
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>>> from qiskit.circuit import QuantumCircuit, Parameter
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>>> angles = [Parameter("angle_1"), Parameter("angle_2"), Parameter("angle_10")]
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>>> circuit = QuantumCircuit(1)
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>>> circuit.u(*angles, 0)
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>>> circuit.draw()
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┌─────────────────────────────┐
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q: ┤ U(angle_1,angle_2,angle_10) ├
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└─────────────────────────────┘
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>>> circuit.parameters
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ParameterView([Parameter(angle_1), Parameter(angle_10), Parameter(angle_2)])
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```
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To respect numerical sorting, a [`ParameterVector`](qiskit.circuit.ParameterVector "qiskit.circuit.ParameterVector") can be used.
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```python
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>>> from qiskit.circuit import QuantumCircuit, Parameter, ParameterVector
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>>> x = ParameterVector("x", 12)
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>>> circuit = QuantumCircuit(1)
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>>> for x_i in x:
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... circuit.rx(x_i, 0)
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>>> circuit.parameters
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ParameterView([
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ParameterVectorElement(x[0]), ParameterVectorElement(x[1]),
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ParameterVectorElement(x[2]), ParameterVectorElement(x[3]),
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..., ParameterVectorElement(x[11])
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])
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```
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**Returns**
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The sorted [`Parameter`](qiskit.circuit.Parameter "qiskit.circuit.Parameter") objects in the circuit.
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</Attribute>
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### prefix
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.prefix" attributeValue="'circuit'" />
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### qubits
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.qubits">
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A list of `Qubit`s in the order that they were added. You should not mutate this.
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</Attribute>
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### name
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.name" attributeTypeHint="str">
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A human-readable name for the circuit.
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</Attribute>
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### qregs
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.qregs" attributeTypeHint="list[QuantumRegister]">
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A list of the `QuantumRegister`s in this circuit. You should not mutate this.
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</Attribute>
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### cregs
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.cregs" attributeTypeHint="list[ClassicalRegister]">
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A list of the `ClassicalRegister`s in this circuit. You should not mutate this.
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</Attribute>
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### duration
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.duration" attributeTypeHint="int | float | None">
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The total duration of the circuit, set by a scheduling transpiler pass. Its unit is specified by [`unit`](#qiskit.circuit.library.CDKMRippleCarryAdder.unit "qiskit.circuit.library.CDKMRippleCarryAdder.unit").
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</Attribute>
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### unit
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<Attribute id="qiskit.circuit.library.CDKMRippleCarryAdder.unit">
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The unit that [`duration`](#qiskit.circuit.library.CDKMRippleCarryAdder.duration "qiskit.circuit.library.CDKMRippleCarryAdder.duration") is specified in.
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</Attribute>
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</Class>
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