Working FFTs

src/fft/radix2.rs

@@ -1,19 +1,20 @@
 // Cooley-Tukey algorithm
 
 use crate::complex::Complex32;
-use crate::fft::DFT;
+use crate::fft::{DFT, FFTDirection};
 use std::f32::consts::PI;
 
 pub struct Radix2FFT {
     output_buffer: Box<[Complex32]>,
     input_buffer: Box<[Complex32]>,
+    direction: FFTDirection,
     size: usize,
     length: usize,
 }
 
 impl DFT for Radix2FFT {
     // Size as power of two
-    fn create(size: usize) -> Self {
+    fn create(size: usize, direction: FFTDirection) -> Self {
         if !is_power_of_two(size) {
             panic!("Tried to create a Radix2 FFT with a non power of two size.");
         }
@@ -22,6 +23,7 @@ impl DFT for Radix2FFT {
             output_buffer: vec![Complex32::zero(); size].into_boxed_slice(),
             input_buffer: vec![Complex32::zero(); size].into_boxed_slice(),
             size: size.ilog2() as usize,
+            direction,
             length: size,
         }
     }
@@ -41,7 +43,7 @@ impl DFT for Radix2FFT {
                     // Compute current polynomial at each unit root
                     let a = self.output_buffer[s + i];
                     let b = self.output_buffer[s + i + mid_point];
-                    let angle = -2. * PI * (i as f32) / (pol_length as f32);
+                    let angle = -2. * self.direction.sign() * PI * (i as f32) / (pol_length as f32);
                     let phasor = Complex32::cexp(angle);
                     self.output_buffer[i + s] = a + phasor * b;
                     self.output_buffer[i + s + mid_point] = a - phasor * b;