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  "framework" : "Accelerate",
  "identifier" : "/documentation/Accelerate/BNNS/applyInTopK(k:input:testIndices:output:axis:batchSize:filterParameters:)",
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  "title" : "applyInTopK(k:input:testIndices:output:axis:batchSize:filterParameters:)"
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# applyInTopK(k:input:testIndices:output:axis:batchSize:filterParameters:)

Applies an in-top-k filter directly to an input.

```
static func applyInTopK(k: Int, input: BNNSNDArrayDescriptor, testIndices: BNNSNDArrayDescriptor, output: BNNSNDArrayDescriptor, axis: Int, batchSize: Int, filterParameters: BNNSFilterParameters? = nil) throws
```

## Parameters

`k`

The number of entries the operation finds.

`input`

The descriptor of the input.

`testIndices`

The descriptor of the test indices.

`output`

The descriptor of the output.

`axis`

The axis along which the operation finds top-k entries.

`batchSize`

The number of input-output pairs to process.

`filterParameters`

The filter runtime parameters.

## Discussion

> Important:
> The input data type must be `float`, the test indices data type must be `int32`, and the output data type must be `BNNSDataTypeBoolean`.

## See Also

[`func BNNSDirectApplyInTopK(Int, Int, Int, UnsafePointer<BNNSNDArrayDescriptor>, Int, UnsafePointer<BNNSNDArrayDescriptor>, Int, UnsafeMutablePointer<BNNSNDArrayDescriptor>, Int, UnsafePointer<BNNSFilterParameters>?) -> Int32`](/documentation/Accelerate/BNNSDirectApplyInTopK(_:_:_:_:_:_:_:_:_:_:))

Applies an in-top-k filter directly to an input.


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