# Fractional part extraction Truncate the elements of a vector to a fraction. ## Topics ### Single-Vector Fractional Part Extraction The functions in this group remove the whole-number part of each element in a vector, leaving the fractional part in the output vector. [`static func trunc(U) -> [Double]`](/documentation/Accelerate/vDSP/trunc(_:)-80rfo) Returns a double-precision array containing each element in the supplied vector truncated to a fraction. [`static func trunc(U) -> [Float]`](/documentation/Accelerate/vDSP/trunc(_:)-1npgt) Returns a single-precision array containing each element in the supplied vector truncated to a fraction. [`static func trunc(U, result: inout V)`](/documentation/Accelerate/vDSP/trunc(_:result:)-4t63c) Calculates each element in the supplied double-precision vector truncated to a fraction. [`static func trunc(U, result: inout V)`](/documentation/Accelerate/vDSP/trunc(_:result:)-fabn) Calculates each element in the supplied single-precision vector truncated to a fraction. [`extern void vDSP_vfrac(const float *__A, vDSP_Stride __IA, float *__C, vDSP_Stride __IC, vDSP_Length __N);`](/documentation/Accelerate/vDSP_vfrac) Truncates the elements of a single-precision vector to fractions. [`extern void vDSP_vfracD(const double *__A, vDSP_Stride __IA, double *__C, vDSP_Stride __IC, vDSP_Length __N);`](/documentation/Accelerate/vDSP_vfracD) Truncates the elements of a double-precision vector to fractions. --- 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)