<!--
{
  "availability" : [
    "iOS: 14.0.0 - 18.0.0",
    "iPadOS: 14.0.0 - 18.0.0",
    "macCatalyst: 14.0.0 - 18.0.0",
    "macOS: 11.0.0 - 15.0.0",
    "tvOS: 14.0.0 - 18.0.0",
    "visionOS: 1.0.0 - 2.0.0",
    "watchOS: 7.0.0 - 11.0.0"
  ],
  "documentType" : "symbol",
  "framework" : "Accelerate",
  "identifier" : "/documentation/Accelerate/BNNSLayerParametersLSTM/sequence_descriptor",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Property",
  "symbol" : {
    "kind" : "Instance Property",
    "modules" : [
      "Accelerate"
    ],
    "preciseIdentifier" : "c:@SA@BNNSLayerParametersLSTM@FI@sequence_descriptor"
  },
  "title" : "sequence_descriptor"
}
-->

# sequence_descriptor

A 1D array of unsigned-integer elements that determines the batch size for each step.

```
var sequence_descriptor: BNNSNDArrayDescriptor
```

## Discussion

If [`seq_len`](/documentation/Accelerate/BNNSLayerParametersLSTM/seq_len) is greater than `1` and the [`data`](/documentation/Accelerate/BNNSNDArrayDescriptor/data) property of this descriptor is `nil`, BNNS uses the same [`batch_size`](/documentation/Accelerate/BNNSLayerParametersLSTM/batch_size) for the entire sequence.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)