---
title: vDSP_fft2d_zipD
framework: accelerate
role: symbol
role_heading: Function
path: accelerate/vdsp_fft2d_zipd
---

# vDSP_fft2d_zipD

Computes a 2D forward or inverse in-place, double-precision complex FFT.

## Declaration

```occ
extern void vDSP_fft2d_zipD(FFTSetupD __Setup, const DSPDoubleSplitComplex *__C, vDSP_Stride __IC0, vDSP_Stride __IC1, vDSP_Length __Log2N0, vDSP_Length __Log2N1, FFTDirection __Direction);
```

## Parameters

- `__Setup`: The FFT setup structure for this transform. The setup’s structure Log2N must be greater than or equal to this function’s Log2N0 and Log2N1.
- `__C`: A pointer to the input-output data.
- `__IC0`: The stride between the elements in a row of C, set to 1 for best performance.
- `__IC1`: The increment, in elements, between consecutive elements in a column of A, which is also the distance between adjacent rows of A. Unless A is a submatrix, pass 0 to have the function calculate the default column stride as the row stride ( __IA0) multiplied by the column count.
- `__Log2N0`: The base 2 exponent of the number of columns to process for each row.
- `__Log2N1`: The base 2 exponent of the number of rows to process. For example, to process 64 rows of 128 columns, specify 7 for Log2N0 and 6 for Log2N1.
- `__Direction`: A flag that specifies the transform direction. Pass doc://com.apple.documentation/documentation/kernel/1645049-anonymous/kfftdirection_forward to transform from the spatial domain to the frequency domain. Pass doc://com.apple.documentation/documentation/kernel/1645049-anonymous/kfftdirection_inverse to transform from the frequency domain to the spatial domain.

## Discussion

Discussion tip: To learn how the vDSP library scales and arranges the FFT output, see Understanding data packing for Fourier transforms.

## See Also

### In-Place FFT Functions

- [vDSP_fft2d_zip](accelerate/vdsp_fft2d_zip.md)