---
title: BindFragmentDepths (latest version)
description: API reference for qiskit_noise_learning.experiment_builder.BindFragmentDepths in the latest version of qiskit-noise-learning
source: https://quantum.cloud.ibm.com/docs/en/api/qiskit-noise-learning/generated/experiment-builder-bind-fragment-depths
---

# qiskit\_noise\_learning.experiment\_builder.BindFragmentDepths

*class* `qiskit_noise_learning.experiment_builder.BindFragmentDepths(fragment_depths: list[int])`

[GitHub](https://github.com/Qiskit/qiskit-noise-learning/tree/stable/0.1/qiskit_noise_learning/experiment_builder/stages/bind_fragment_depths.py)

Bases: [`ExperimentBuilderStage`](/docs/api/qiskit-noise-learning/generated/experiment-builder-experiment-builder-stage "qiskit_noise_learning.experiment_builder.experiment_builder_stage.ExperimentBuilderStage")

Expand unbound instruction sequences at the given fragment depths.

Each unbound instruction sequence is replaced by a bound copy at each fragment depth. Bound sequences are kept as-is. The `randomization_multipliers` and `relations` are updated accordingly: the multiplier of an unbound sequence is propagated to all its bound expansions, and any relation pointing to an unbound sequence is fanned out to all the resulting bound sequences.

**Parameters**

**fragment\_depths** – The fragment depths at which to bind unbound sequences.

### \_\_init\_\_

`__init__(fragment_depths: list[int])`

## Methods

|                                                                                                                                                                              |                                                  |
| ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------ |
| [`__init__`](#qiskit_noise_learning.experiment_builder.BindFragmentDepths.__init__ "qiskit_noise_learning.experiment_builder.BindFragmentDepths.__init__")(fragment\_depths) |                                                  |
| `run`(experiment)                                                                                                                                                            | Validate required fields, then apply this stage. |

## Attributes

|                    |   |
| ------------------ | - |
| `populates_fields` |   |
| `required_fields`  |   |