# pytket.placement

In order for the constraints of a {py:class}`Backend` to be solved we must first assign device qubits to device-independent (or program) qubits.
This module contains three placement methods to perform such an assignment.

For more on qubit placement (and routing in general) see the [qubit mapping and routing](https://docs.quantinuum.com/tket/user-guide/examples/circuit_compilation/mapping_example.html) tutorial and the corresponding entry in the [user manual](https://docs.quantinuum.com/tket/user-guide/manual/manual_compiler.html#placement).

```{eval-rst}
.. currentmodule:: pytket._tket.placement
```

```{eval-rst}
.. automodule:: pytket.placement
```

```{eval-rst}
.. automodule:: pytket._tket.placement
```

```{eval-rst}
.. autoclass:: pytket.placement.GraphPlacement

   .. automethod:: __init__
   .. automethod:: to_dict
```

```{eval-rst}
.. autoclass:: pytket.placement.LinePlacement

   .. automethod:: __init__
   .. automethod:: to_dict
```

```{eval-rst}
.. autoclass:: pytket.placement.NoiseAwarePlacement

   .. automethod:: __init__
   .. automethod:: to_dict
```

```{eval-rst}
.. autoclass:: pytket.placement.Placement

   .. automethod:: __init__
   .. automethod:: from_dict
   .. automethod:: get_placement_map
   .. automethod:: get_placement_maps
   .. automethod:: place
   .. automethod:: place_with_map
   .. automethod:: to_dict
```

```{eval-rst}
.. automethod:: pytket.placement.place_fully_connected
```

```{eval-rst}
.. automethod:: pytket.placement.place_with_map
```