---
title: ApproximateCircuit (latest version)
description: API reference for qiskit.synthesis.unitary.aqc.ApproximateCircuit in the latest version of qiskit
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/qiskit.synthesis.unitary.aqc.ApproximateCircuit
---

# ApproximateCircuit

*class* `qiskit.synthesis.unitary.aqc.ApproximateCircuit(num_qubits, name=None)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.5/qiskit/synthesis/unitary/aqc/approximate.py#L21-L52)

Bases: [`QuantumCircuit`](/docs/api/qiskit/qiskit.circuit.QuantumCircuit "qiskit.circuit.quantumcircuit.QuantumCircuit"), [`ABC`](https://docs.python.org/3/library/abc.html#abc.ABC)

A base class that represents an approximate circuit.

**Parameters**

- **num\_qubits** ([*int*](https://docs.python.org/3/library/functions.html#int)) – number of qubits this circuit will span.
- **name** ([*str*](https://docs.python.org/3/library/stdtypes.html#str)) – a name of the circuit.

## Attributes

### thetas

The property is not implemented and raises a `NotImplementedError` exception.

**Returns**

a vector of parameters of this circuit.

### name

Type: [`str`](https://docs.python.org/3/library/stdtypes.html#str)

A human-readable name for the circuit.

**Example**

```python
from qiskit import QuantumCircuit

qc = QuantumCircuit(2, 2, name="my_circuit")
print(qc.name)
```

```text
my_circuit
```

## Methods

### build

*abstractmethod* `build(thetas)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.5/qiskit/synthesis/unitary/aqc/approximate.py#L43-L52)

**Constructs this circuit out of the parameters(thetas). Parameter values must be set before**

constructing the circuit.

**Parameters**

**thetas** ([*ndarray*](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.html#numpy.ndarray)) – a vector of parameters to be set in this circuit.

**Return type**

None