# vDSP_vsorti Performs an in-place sort of the indices into a single-precision vector. ``` extern void vDSP_vsorti(const float *__C, vDSP_Length *__I, vDSP_Length *__Temporary, vDSP_Length __N, int __Order); ``` ## Parameters `__C` The input vector that defines the source values. `__I` The input vector that defines the indices. On input, the values `0 ..< n`. On output, the sorted indices. `__Temporary` A temporary vector that this function doesn’t use. Pass `nil`. `__N` The number of elements in the vector. `__Order` A value that specifies the sort order. Pass `1` to specify ascending order, or `-1` for descending order. ## Discussion The following code sorts the indices into an array in ascending order, followed by decending order: ```swift let values: [Float] = [4.0, 8.0, 3.0, 0.0, 7.0, 5.0, 9.0, 2.0, 6.0, 1.0] let n = vDSP_Length(values.count) var indices = ( 0 ..< n ).map { $0 } vDSP_vsorti(values, &indices, nil, n, 1) // Prints "[0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0]". print(indices.map { values[Int($0)] }) vDSP_vsorti(values, &indices, nil, n, -1) // Prints "[9.0, 8.0, 7.0, 6.0, 5.0, 4.0, 3.0, 2.0, 1.0, 0.0]". print(indices.map { values[Int($0)] }) ``` Note that this function doesn’t provide a stable sort. So, if the function compares two elements as equal, it may place them in any order within the sorted array. --- Copyright © 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)