# vDSP.ThresholdRule Constants that specify vector threshold rules. ``` enum ThresholdRule where T : BinaryFloatingPoint ``` ## Topics ### Threshold rules [`case clampToThreshold`](/documentation/Accelerate/vDSP/ThresholdRule/clampToThreshold) Returns the threshold if the input value is less than threshold; otherwise returns the input value. [`case signedConstant(T)`](/documentation/Accelerate/vDSP/ThresholdRule/signedConstant(_:)) Returns the negated constant if the input value is less than the threshold; otherwise returns the constant. [`case zeroFill`](/documentation/Accelerate/vDSP/ThresholdRule/zeroFill) Returns `0` if the input value is less than the threshold; otherwise returns the input value. --- 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)