Merge remote-tracking branch 'origin/dev' into dev

src/filters_and_windows/flat_top.rs

@@ -0,0 +1,18 @@
+/// Creates a flat top filter of size n
+/// 
+/// 
+/// uses matlab constants, these constants will change the filter.
+/// i - Offset add offset maybe other var to take in?
+pub fn flat_top_window<const N: usize>(offset:usize) -> [f32; N] {
+    const A_0: f32 =0.21557895;
+    const A_1: f32 =0.41663158;
+    const A_2: f32 =0.277263158;
+    const A_3: f32 =0.083578947;
+    const A_4: f32 =0.006947368;
+    let mut filter: [f32;N] = [0.0; N];
+    for i in 0..N{
+      let n = (i as f32) - (offset as f32);
+       filter[i] = A_0 - A_1 * f32::cos(((2 as f32 * std::f32::consts::PI * n as f32)/N as f32)) + A_2 * f32::cos(((4 as f32 * std::f32::consts::PI * n as f32)/N as f32)) - A_3 * f32::cos(((6 as f32 * std::f32::consts::PI * n as f32)/N as f32)) + A_4 * f32::cos(((8 as f32 * std::f32::consts::PI * n as f32)/N as f32));
+    }
+   filter
+}

src/filters_and_windows/mod.rs

@@ -4,3 +4,4 @@ pub mod gaussian_window;
 pub mod hamming;
 pub mod triangle;
 pub mod sin;
+pub mod flat_top;

tests/flat_top.rs

@@ -0,0 +1,35 @@
+// Test Flat Top Window
+
+use superdsp::filters_and_windows::flat_top;
+
+const N_SHORT: usize = 16;
+
+#[test]
+pub fn flat_top_window_short(){
+    let expected = [
+        -0.00042,
+        -0.00527,
+        -0.02687,
+        -0.0627,
+        -0.05474,
+        0.10175,
+        0.44414,
+        0.82854,
+        1.0,
+        0.82854,
+        0.44414,
+        0.10175,
+        -0.05474,
+        -0.0627,
+        -0.02687,
+        -0.00527,
+    ];
+
+    let window = flat_top::flat_top_window::<N_SHORT>(0);
+    assert_eq!(window.len(), N_SHORT);
+
+    // make sure the window is correct to 4 decimal places (floating point error)
+    for i in 0..N_SHORT {
+        assert!((window[i] - expected[i]).abs() < 0.0001);
+    }
+}