# sum(_:) Returns the double-precision vector sum. ``` static func sum(_ vector: U) -> Double where U : AccelerateBuffer, U.Element == Double ``` ## Parameters `vector` The vector to sum. ## Discussion This function calculates and returns the sum of the elements of a supplied vector. The following is an example of using [`sum(_:)`](/documentation/Accelerate/vDSP/sum(_:)-8hq9): ```swift let a: [Double] = [-1.5, 2.25, 3.6, 0.2, -0.1, -4.3] let sum = vDSP.sum(a) // Prints "sum 0.1500" print(String(format: "sum %.4f", sum)) ``` --- 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)