<!--
{
  "availability" : [
    "iOS: 16.0.0 -",
    "iPadOS: 16.0.0 -",
    "macCatalyst: 16.0.0 -",
    "macOS: 13.0.0 -",
    "tvOS: 16.0.0 -",
    "visionOS: 1.0.0 -",
    "watchOS: 9.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "Accelerate",
  "identifier" : "/documentation/Accelerate/vDSP_biquadm_SetTargetsDoubleD",
  "metadataVersion" : "0.1.0",
  "role" : "Function",
  "symbol" : {
    "kind" : "Function",
    "modules" : [
      "Accelerate"
    ],
    "preciseIdentifier" : "c:@F@vDSP_biquadm_SetTargetsDoubleD"
  },
  "title" : "vDSP_biquadm_SetTargetsDoubleD"
}
-->

# vDSP_biquadm_SetTargetsDoubleD

Sets the double-precision coefficient target values of the specified double-precision, multichannel biquadratic filter setup object.

```
extern void vDSP_biquadm_SetTargetsDoubleD(vDSP_biquadm_SetupD __setup, const double *__targets, double __interp_rate, double __interp_threshold, vDSP_Length __start_sec, vDSP_Length __start_chn, vDSP_Length __nsec, vDSP_Length __nchn);
```

## Parameters

`__setup`

The biquadratic filter setup object that the function updates.

`__targets`

The array of coefficient target values.

`__interp_rate`

The rate constant that determines the size of increments that each call to [`vDSP_biquadmD`](/documentation/Accelerate/vDSP_biquadmD) applies to the coefficient values. The rate must be in the range `0` to `1`; otherwise, the function’s behavior is undefined.

`__interp_threshold`

The threshold constant that determines how close a coefficient’s value must be to the target value before incrementation stops. The threshold must be greater than zero; otherwise, the function’s behavior is undefined.

`__start_sec`

The first section in each channel that the function updates.

`__start_chn`

The first channel that the function updates.

`__nsec`

The number of sections in each channel that the function updates.

`__nchn`

The number of channels that the function updates.

## Discussion

This function sets target values for the biquadratic filter’s coefficients. Each subsequent call to [`vDSP_biquadmD`](/documentation/Accelerate/vDSP_biquadmD) increments the coefficients until the difference between their values and their corresponding target is less than a specified threshold.

The size of the increment for each selected coefficient is a function of the `__interp_rate` constant and the difference between the target value and the initial value.

This function doesn’t allocate any additional memory.

The `__targets` array must only contain the new target values, and you must specify these with the same structure as the original coefficients. For more information, see [`vDSP_biquadm_CreateSetupD`](/documentation/Accelerate/vDSP_biquadm_CreateSetupD).

---

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)