---
title: "BNNSNearestNeighborsGetInfo(_:_:_:_:)"
framework: accelerate
role: symbol
role_heading: Function
path: "accelerate/bnnsnearestneighborsgetinfo(_:_:_:_:)"
---

# BNNSNearestNeighborsGetInfo(_:_:_:_:)

Calculates the sorted indices and Euclidean distances of the k-nearest neighbors to a specified sample data point.

## Declaration

```swift
func BNNSNearestNeighborsGetInfo(_ knn: BNNSNearestNeighbors?, _ sample_number: Int32, _ indices: UnsafeMutablePointer<Int32>?, _ distances: UnsafeMutableRawPointer?) -> Int32
```

## Parameters

- `knn`: The k-nearest neighbors object.
- `sample_number`: The index of the sample data point of which the function computes the k-nearest neighbors.
- `indices`: On return, the sorted indices of the k-nearest neighbors to the sample data point.
- `distances`: On return, the sorted distances of the k-nearest neighbors to the sample data point.

## Return Value

Return Value 0 when the operation is successful; otherwise, a nonzero value.

## Discussion

Discussion The following code generates eight 2D data points and loads them into a k-nearest neighbors object with a single call to the BNNSNearestNeighborsLoad(_:_:_:) function. The code then computes the four nearest neighbors, based on Euclidean distance, to the sample data point at index 7 of the samples data. let samples: [Float] = [     1, 2,   // 0     7, 2,   // 1     3, 4,   // 2     8, 4,   // 3     3, 7,   // 4     7, 7,   // 5     2, 8,   // 6     2, 5    // 7 ]

let maximumSampleCount: UInt32 = 8 let dimensionCount: UInt32 = 2 let nearestNeighborCount: UInt32 = 4

let knn = BNNSCreateNearestNeighbors(     maximumSampleCount,     dimensionCount,     nearestNeighborCount,     BNNSDataType.float,     nil)

defer {     BNNSDestroyNearestNeighbors(knn) }

BNNSNearestNeighborsLoad(     knn,     UInt32(samples.count) / dimensionCount,     samples)

var indices = [Int32](repeating: 0,                       count: Int(nearestNeighborCount)) var distances = [Float](repeating: 0,                         count: Int(nearestNeighborCount))

let sampleDataPointIndex = 7 BNNSNearestNeighborsGetInfo(     knn,     Int32(sampleDataPointIndex),     &indices,     &distances) On return, the indices array contains the values [7, 2, 4, 6] and the distances array contains the values [0.0, 1.4142135, 2.236068, 3.0].

## See Also

### K-nearest neighbors calculation

- [BNNS.NearestNeighbors](accelerate/bnns/nearestneighbors.md)
- [BNNSNearestNeighbors](accelerate/bnnsnearestneighbors.md)
- [BNNSCreateNearestNeighbors(_:_:_:_:_:)](accelerate/bnnscreatenearestneighbors(_:_:_:_:_:).md)
- [BNNSNearestNeighborsLoad(_:_:_:)](accelerate/bnnsnearestneighborsload(_:_:_:).md)
- [BNNSDestroyNearestNeighbors(_:)](accelerate/bnnsdestroynearestneighbors(_:).md)