# MCMT

`qiskit.circuit.library.MCMT(gate, num_ctrl_qubits, num_target_qubits)`

Bases: `QuantumCircuit`

The multi-controlled multi-target gate, for an arbitrary singly controlled target gate.

For example, the H gate controlled on 3 qubits and acting on 2 target qubit is represented as:

```
───■────
│
───■────
│
───■────
┌──┴───┐
┤0 ├
│ 2-H │
┤1 ├
└──────┘
```

This default implementations requires no ancilla qubits, by broadcasting the target gate to the number of target qubits and using Qiskit’s generic control routine to control the broadcasted target on the control qubits. If ancilla qubits are available, a more efficient variant using the so-called V-chain decomposition can be used. This is implemented in `MCMTVChain`

.

Create a new multi-control multi-target gate.

**Parameters**

**gate**(*Gate**| Callable[[**QuantumCircuit**,**Qubit**,**Qubit**],**circuit.Instruction**]*) – The gate to be applied controlled on the control qubits and applied to the target qubits. Can be either a Gate or a circuit method. If it is a callable, it will be casted to a Gate.**num_ctrl_qubits**(*int*(opens in a new tab)) – The number of control qubits.**num_target_qubits**(*int*(opens in a new tab)) – The number of target qubits.

**Raises**

**AttributeError**(opens in a new tab) – If the gate cannot be casted to a controlled gate.**AttributeError**(opens in a new tab) – If the number of controls or targets is 0.

## Attributes

### ancillas

Returns a list of ancilla bits in the order that the registers were added.

### calibrations

Return calibration dictionary.

The custom pulse definition of a given gate is of the form `{'gate_name': {(qubits, params): schedule}}`

### clbits

Returns a list of classical bits in the order that the registers were added.

### data

Return the circuit data (instructions and context).

**Returns**

a list-like object containing the `CircuitInstruction`

s for each instruction.

**Return type**

QuantumCircuitData

### extension_lib

`= 'include "qelib1.inc";'`

### global_phase

Return the global phase of the current circuit scope in radians.

### header

`= 'OPENQASM 2.0;'`

### instances

`= 219`

### layout

Return any associated layout information about the circuit

This attribute contains an optional `TranspileLayout`

object. This is typically set on the output from `transpile()`

or `PassManager.run()`

to retain information about the permutations caused on the input circuit by transpilation.

There are two types of permutations caused by the `transpile()`

function, an initial layout which permutes the qubits based on the selected physical qubits on the `Target`

, and a final layout which is an output permutation caused by `SwapGate`

s inserted during routing.

### 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.

### num_ancilla_qubits

Return the number of ancillas.

### num_ancillas

Return the number of ancilla qubits.

### num_clbits

Return number of classical bits.

### num_parameters

The number of parameter objects in the circuit.

### num_qubits

Return number of qubits.

### op_start_times

Return a list of operation start times.

This attribute is enabled once one of scheduling analysis passes runs on the quantum circuit.

**Returns**

List of integers representing instruction start times. The index corresponds to the index of instruction in `QuantumCircuit.data`

.

**Raises**

**AttributeError** (opens in a new tab) – When circuit is not scheduled.

### parameters

The parameters defined in the circuit.

This attribute returns the `Parameter`

objects in the circuit sorted alphabetically. Note that parameters instantiated with a `ParameterVector`

are still sorted numerically.

## Examples

The snippet below shows that insertion order of parameters does not matter.

```
>>> from qiskit.circuit import QuantumCircuit, Parameter
>>> a, b, elephant = Parameter("a"), Parameter("b"), Parameter("elephant")
>>> circuit = QuantumCircuit(1)
>>> circuit.rx(b, 0)
>>> circuit.rz(elephant, 0)
>>> circuit.ry(a, 0)
>>> circuit.parameters # sorted alphabetically!
ParameterView([Parameter(a), Parameter(b), Parameter(elephant)])
```

Bear in mind that alphabetical sorting might be unintuitive when it comes to numbers. The literal “10” comes before “2” in strict alphabetical sorting.

```
>>> from qiskit.circuit import QuantumCircuit, Parameter
>>> angles = [Parameter("angle_1"), Parameter("angle_2"), Parameter("angle_10")]
>>> circuit = QuantumCircuit(1)
>>> circuit.u(*angles, 0)
>>> circuit.draw()
┌─────────────────────────────┐
q: ┤ U(angle_1,angle_2,angle_10) ├
└─────────────────────────────┘
>>> circuit.parameters
ParameterView([Parameter(angle_1), Parameter(angle_10), Parameter(angle_2)])
```

To respect numerical sorting, a `ParameterVector`

can be used.

` `

```
>>> from qiskit.circuit import QuantumCircuit, Parameter, ParameterVector
>>> x = ParameterVector("x", 12)
>>> circuit = QuantumCircuit(1)
>>> for x_i in x:
... circuit.rx(x_i, 0)
>>> circuit.parameters
ParameterView([
ParameterVectorElement(x[0]), ParameterVectorElement(x[1]),
ParameterVectorElement(x[2]), ParameterVectorElement(x[3]),
..., ParameterVectorElement(x[11])
])
```

**Returns**

The sorted `Parameter`

objects in the circuit.

### prefix

`= 'circuit'`

### qubits

Returns a list of quantum bits in the order that the registers were added.

## Methods

### control

`control(num_ctrl_qubits=1, label=None, ctrl_state=None)`

Return the controlled version of the MCMT circuit.

### inverse

`inverse()`

Return the inverse MCMT circuit, which is itself.