---
title: Out-of-Place Functions for 1D Complex FFT
framework: accelerate
role: collectionGroup
role_heading: API Collection
path: accelerate/out-of-place-functions-for-1d-complex-fft
---

# Out-of-Place Functions for 1D Complex FFT

Perform fast Fourier transforms out of place on 1D complex data.

## Overview

Overview The functions in this group use the following operation for a complex-to-complex transform: N = 1 << Log2N;

scale = 0 < Direction ? 1 : 1./N;

// Define a complex vector, h: for (j = 0; j < N; ++j)     h[j] = A->realp[j*IA] + i * A->imagp[j*IA];

// Perform Discrete Fourier Transform. for (k = 0; k < N; ++k)     H[k] = scale * sum(h[j] * e**(-Direction*2*pi*i*j*k/N), 0 <= j < N);

// Store result. for (k = 0; k < N; ++k) {     C->realp[k*IC] = Re(H[k]);     C->imagp[k*IC] = Im(H[k]); }

The temporary buffer versions perform the same operation but use a temporary buffer for improved performance.

## See Also

### Functions for 1D Complex FFT

- [In-Place Functions for 1D Complex FFT](accelerate/in-place-functions-for-1d-complex-fft.md)