# subtract(multiplication:_:result:) Calculates the single-precision element-wise difference of a vector and the product of two vectors. ``` static func subtract(multiplication: (a: T, b: U), _ vector: S, result: inout V) where S : AccelerateBuffer, T : AccelerateBuffer, U : AccelerateBuffer, V : AccelerateMutableBuffer, S.Element == Float, T.Element == Float, U.Element == Float, V.Element == Float ``` ## Parameters `multiplication` A tuple that contains the vectors `A` and `B` in `D = (A * B) - C`. `vector` The input vector `C` in `D = (A * B) - C`. `result` The output vector `D` in `D = (A * B) - C`. ## Discussion This function calculates the products of the first `N` elements of `A` and `B`, subtracts each product from the corresponding value in `C`, and writes the result to `D`. ```swift for (n = 0; n < N; ++n) D[n] = (A[n] * B[n]) - C[n]; ```  The following code shows an example of using this function: ```swift let count = 5 let a: [Float] = [ 1, 2, 3, 4, 5] let b: [Float] = [10, 20, 30, 40, 50] let c: [Float] = [ 5, 4, 3, 2, 1] let d = [Float](unsafeUninitializedCapacity: count) { buffer, initializedCount in vDSP.subtract(multiplication: (a, b), c, result: &buffer) initializedCount = count } // Prints "[5.0, 36.0, 87.0, 158.0, 249.0]". print(d) ``` --- 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)