---
title: GroupGatesIntoBoxes (latest version)
description: API reference for samplomatic.transpiler.passes.GroupGatesIntoBoxes in the latest version of samplomatic
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/samplomatic/auto/transpiler-passes-group-gates-into-boxes
---

# GroupGatesIntoBoxes

*class* `samplomatic.transpiler.passes.GroupGatesIntoBoxes(*args, **kwargs)`

[GitHub](https://github.com/Qiskit/samplomatic/tree/main/samplomatic/transpiler/passes/group_gates_into_boxes.py#L47-L146)

Bases: [`TransformationPass`](/docs/api/qiskit/qiskit.transpiler.TransformationPass)

Collect the two-qubit gates in a circuit inside left-dressed boxes.

This pass collects all 2-qubit gates in the input circuit into left-dressed boxes. To assign the gates to these boxes, it uses a greedy collection strategy. By default (`strategy="asap"`) it places each gate in the earliest possible box. When `strategy="alap"` it places each gate in the latest possible box.

> **Note**
>
> Barriers and boxes that are present in the input circuit act as delimiters. This means that when the pass encounters one of these delimiters acting on a subset of qubits, it immediately terminates the collection for those qubits and flushes the collected gates into a left-dressed box. The delimiters themselves remain present in the output circuit, but are placed outside of any boxes.

> **Note**
>
> Measurements and resets also act as delimiters.

> **Note**
>
> The circuits returned by this pass may not be buildable. To make them buildable, one can either use [`AddTerminalRightDressedBoxes`](/docs/api/samplomatic/auto/transpiler-passes-add-terminal-right-dressed-boxes "samplomatic.transpiler.passes.AddTerminalRightDressedBoxes") to add right-dressed “collector” boxes.

**Methods Summary**

|                                                                                                                              |                                                              |
| ---------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------ |
| [`run`](#samplomatic.transpiler.passes.GroupGatesIntoBoxes.run "samplomatic.transpiler.passes.GroupGatesIntoBoxes.run")(dag) | Collect the operations in the dag inside left-dressed boxes. |

**Methods Documentation**

### run

`run(dag: DAGCircuit) → DAGCircuit`

[GitHub](https://github.com/Qiskit/samplomatic/tree/main/samplomatic/transpiler/passes/group_gates_into_boxes.py#L80-L93)

Collect the operations in the dag inside left-dressed boxes.

**The collection strategy undertakes the following steps:**

- Loop through the DAG’s op nodes in topological order (ASAP) or reverse topological order (ALAP).
- Group together two-qubit gate nodes that need to be placed in the same box.
- Whenever a node can be placed in more than one group, place it in the earliest possible group (ASAP) or the latest possible group (ALAP).
- When looping is complete, replace each group with a box.