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/lib.rs        |  1 +
 src/num_traits.rs | 24 +++++++++++++++++++++
 src/sinusoid.rs   | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+)
 create mode 100644 src/sinusoid.rs

(limited to 'src')

diff --git a/src/lib.rs b/src/lib.rs
index 818890f..70b7829 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,2 +1,3 @@
 pub mod complex;
 pub mod num_traits;
+pub mod sinusoid;
diff --git a/src/num_traits.rs b/src/num_traits.rs
index 1e04cce..b6a2ac8 100644
--- a/src/num_traits.rs
+++ b/src/num_traits.rs
@@ -1,3 +1,5 @@
+use std;
+
 pub trait Trig {
     fn sin(self) -> Self;
     fn cos(self) -> Self;
@@ -82,3 +84,25 @@ impl_int_pow!(u8);
 impl_int_pow!(u16);
 impl_int_pow!(u32);
 impl_int_pow!(u64);
+
+
+pub trait Float {
+    fn recip(self) -> Self;
+    fn PI() -> Self;
+}
+
+macro_rules! impl_float {
+    ($t: ty, $pi: expr) => {
+        impl Float for $t {
+            fn recip(self) -> Self {
+                self.recip()
+            }
+            fn PI() -> Self {
+                $pi
+            }
+        }
+    }
+}
+
+impl_float!(f32, std::f32::consts::PI);
+impl_float!(f64, std::f64::consts::PI);
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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