From 885618f96ab1079ee49553f46804d2a4460e41b3 Mon Sep 17 00:00:00 2001
From: Justin Worthe <justin.worthe@gmail.com>
Date: Sat, 3 Dec 2016 21:56:26 +0200
Subject: Started adding sinusoids

---
 src/sinusoid.rs | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 src/sinusoid.rs

(limited to 'src/sinusoid.rs')

diff --git a/src/sinusoid.rs b/src/sinusoid.rs
new file mode 100644
index 0000000..6ee5019
--- /dev/null
+++ b/src/sinusoid.rs
@@ -0,0 +1,63 @@
+use std;
+use std::ops::{Add, Sub, Mul, Div, Neg};
+use ::num_traits::{Trig, Pow, Float};
+
+// generic number type, but realistically it's only useful for
+// floats. Maybe also complex<float>
+
+pub struct Sinusoid<T> {
+    amplitude: T,
+    frequency: T,
+    phase: T
+}
+
+impl<T> Sinusoid<T> {
+    pub fn new(amplitude:T, frequency: T, phase: T) -> Sinusoid<T> {
+        Sinusoid {
+            amplitude: amplitude,
+            frequency: frequency,
+            phase: phase
+        }
+    }
+}
+impl<T> Sinusoid<T> where T: Float + Copy {
+    pub fn period(&self) -> T {
+        self.frequency.recip()
+    }
+}
+impl<T> Sinusoid<T> where T: Float + Add<Output=T> + Mul<Output=T> + From<u8> + Trig + Copy + std::fmt::Display {
+    pub fn radial_frequency(&self) -> T {
+        (T::from(2))*T::PI()*self.frequency
+    }
+    pub fn sample(&self, t: T) -> T {
+        (self.radial_frequency()*t + self.phase).cos() * self.amplitude
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::f32;
+
+    #[test]
+    fn period() {
+        let sinusoid = Sinusoid::new(1.0 as f32, 0.5, 0.0);
+        assert!((sinusoid.period()-2.0) < f32::EPSILON);
+    }
+    #[test]
+    fn radial_f() {
+        let sinusoid = Sinusoid::new(1.0 as f32, 1.0, 0.0);
+        assert!((sinusoid.radial_frequency()-2.0*f32::consts::PI) < f32::EPSILON);
+    }
+
+    #[test]
+    fn sample() {
+        let sinusoid = Sinusoid::new(1.0 as f32, 1.0, -f32::consts::PI/2.0); //AKA sin
+
+        assert!((sinusoid.sample(0.0)-0.0) < f32::EPSILON);
+        assert!((sinusoid.sample(0.25)-1.0) < f32::EPSILON);
+        assert!((sinusoid.sample(0.5)-0.0) < f32::EPSILON);
+        assert!((sinusoid.sample(0.75)+1.0) < f32::EPSILON);
+        assert!((sinusoid.sample(1.0)-0.0) < f32::EPSILON);
+    }
+}
-- 
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