Fft

Destructor

A destructor is present on this object, but not explicitly documented in the source.

Members

Functions

fft

void fft(T[] re, T[] im)

Calculates discrete fourier transform. re should contain the real part of the data and im the imaginary part of the data. The method operates in place - the result is saved back to re and im. Both arrays must be properly aligned - to obtain a properly aligned array you can use allocate.

ifft

void ifft(T[] re, T[] im)

Calculates inverse discrete fourier transform scaled by n. The arguments have the same role as they do in fft.

initialize

void initialize(size_t n)

The Fft constructor. The parameter is the size of data sets that fft and ifft will operate on. I will refer to this number as n in the rest of the documentation for this class.Tables used in fft and ifft are calculated in the constructor.

Static functions

alignment

size_t alignment(size_t n)

Returns requited alignment for use with fft, ifft and scale methods.

allocate

T[] allocate(size_t n)

Allocates an array that is aligned properly for use with fft, ifft and scale methods.

deallocate

void deallocate(T[] arr)

Deallocates an array allocated with allocate.

scale

void scale(T[] data, T k)

Scales an array data by factor k. The array must be properly aligned. To obtain a properly aligned array, use allocate.

1 import std.stdio, std.conv, std.exception;
2 import pfft.pfft;
3 
4 void main(string[] args)
5 {
6     auto n = to!int(args[1]);
7     enforce((n & (n-1)) == 0, "N must be a power of two.");
8 
9     alias Fft!float F;
10 
11     F f;
12     f.initialize(n);
13 
14     auto re = F.allocate(n);
15     auto im = F.allocate(n);
16 
17     foreach(i, _; re)
18         readf("%s %s\n", &re[i], &im[i]);
19 
20     f.fft(re, im);
21 
22     foreach(i, _; re)
23         writefln("%s\t%s", re[i], im[i]);
24 }

• Fft
• Rfft