<!--
{
  "availability" : [
    "iOS: 13.0.0 -",
    "iPadOS: 13.0.0 -",
    "macCatalyst: -",
    "macOS: 10.15.0 -",
    "tvOS: 13.0.0 -",
    "visionOS: -",
    "watchOS: 6.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "Accelerate",
  "identifier" : "/documentation/Accelerate/vDSP/Biquad/apply(input:output:)",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Method",
  "symbol" : {
    "kind" : "Instance Method",
    "modules" : [
      "Accelerate"
    ],
    "preciseIdentifier" : "s:10Accelerate4vDSPO6BiquadV5apply5input6outputyqd___qd_0_zt7ElementQyd__RszAA0A6BufferRd__AA0a7MutableH0Rd_0_AIQyd_0_AJRSr0_lF"
  },
  "title" : "apply(input:output:)"
}
-->

# apply(input:output:)

Applies a single- or double-precision single-channel or multichannel biquad IIR filter, overwriting the supplied output vector.

```
mutating func apply<U, V>(input: U, output: inout V) where T == U.Element, U : AccelerateBuffer, V : AccelerateMutableBuffer, U.Element == V.Element
```

---

Copyright &copy; 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)