Calculate poly degree on new

1 files changed, 59 insertions, 50 deletions

diff --git a/src/poly.rs b/src/poly.rs
index 60eb707..90b7b78 100644
--- a/src/poly.rs
+++ b/src/poly.rs
@@ -5,42 +5,53 @@ use iter::Iter;
 use std::ops::{Add, Sub, Mul, Div};
 
 #[derive(PartialEq, Debug, Clone)]
-pub struct Poly(pub Vec<Number>);
+pub struct Poly {
+    data: Vec<Number>,
+    degree: usize
+}
 
 impl Poly {
+    pub fn new(data: Vec<Number>) -> Poly {
+        let mut i = data.len() - 1;
+        while data[i] == 0.0 && i > 0 {
+            i -= 1;
+        }
+        Poly { data, degree : i }
+    }
+
     fn mono(degree: usize, coefficient: Number) -> Poly {
-        let mut p = vec![0.0; degree + 1];
-        p[degree] = coefficient;
-        Poly(p)
+        if coefficient != 0.0 {
+            let mut p = vec![0.0; degree + 1];
+            p[degree] = coefficient;
+            Poly::new(p)
+        } else {
+            Poly::new(vec![0.0])
+        }
     }
 
     fn degree(&self) -> usize {
-        let mut i = self.0.len() - 1;
-        while self.0[i] == 0.0 && i > 0 {
-            i -= 1;
-        }
-        i
+        self.degree
     }
 
     fn lc(&self) -> Number {
-        self.0[self.degree()]
+        self.data[self.degree()]
     }
 
     fn iter(&self) -> Iter {
-        Iter::new(self.0.clone(), self.degree())
+        Iter::new(self.data.clone(), self.degree())
     }
 
     pub fn eval(&self, n: Number) -> Number {
         let mut r = 0.0;
-        for i in 0..self.0.len() {
-            r += self.0[i] * n.powi(i as i32);
+        for i in 0..self.data.len() {
+            r += self.data[i] * n.powi(i as i32);
         }
         r
     }
 
     fn is_zero(&self) -> bool {
-        for i in 0..self.0.len() {
-            if self.0[i] != 0.0 {
+        for i in 0..self.data.len() {
+            if self.data[i] != 0.0 {
                 return false
             }
         }
@@ -52,7 +63,7 @@ impl Add for &Poly {
     type Output = Poly;
 
     fn add(self, other: Self) -> Poly {
-        Poly(self.iter().zip(other.iter()).map(|(x, y)| {x + y}).collect())
+        Poly::new(self.iter().zip(other.iter()).map(|(x, y)| {x + y}).collect())
     }
 }
 
@@ -60,7 +71,7 @@ impl Sub for &Poly {
     type Output = Poly;
 
     fn sub(self, other: Self) -> Poly {
-        Poly(self.iter().zip(other.iter()).map(|(x, y)| {x - y}).collect())
+        Poly::new(self.iter().zip(other.iter()).map(|(x, y)| {x - y}).collect())
     }
 }
 
@@ -73,12 +84,12 @@ impl Mul for &Poly {
             let mut prefix = vec![0.0; i];
             let mut suffix: Vec<Number> = self.iter()
                 .take(self.degree() + 1)
-                .map(|x| {x * other.0[i]})
+                .map(|x| {x * other.data[i]})
                 .collect();
             prefix.append(&mut suffix);
-            r.push(Poly(prefix));
+            r.push(Poly::new(prefix));
         }
-        r.iter().fold(Poly(vec![0.0]), |acc, x| &acc + x)
+        r.iter().fold(Poly::new(vec![0.0]), |acc, x| &acc + x)
     }
 }
 
@@ -86,7 +97,7 @@ impl Div for &Poly {
     type Output = (Poly, Poly);
 
     fn div(self, divisor: Self) -> (Poly, Poly) {
-        let mut q = Poly(vec![0.0]);
+        let mut q = Poly::new(vec![0.0]);
         let mut r = self.clone();
         while !r.is_zero() && r.degree() >= divisor.degree() {
             let s = Poly::mono(r.degree() - divisor.degree(), r.lc() / divisor.lc());
@@ -112,76 +123,74 @@ mod tests {
 
     #[test]
     fn div_equal() {
-        let a = Poly(vec![6.0, 7.0, 1.0]);
-        let b = Poly(vec![-6.0, -5.0, 1.0]);
-        assert_eq!(&a / &b, (Poly(vec![1.0]), Poly(vec![12.0, 12.0, 0.0])));
+        let a = Poly::new(vec![6.0, 7.0, 1.0]);
+        let b = Poly::new(vec![-6.0, -5.0, 1.0]);
+        assert_eq!(&a / &b, (Poly::new(vec![1.0]), Poly::new(vec![12.0, 12.0, 0.0])));
     }
 
     #[test]
     fn div_greater() {
-        let a = Poly(vec![-6.0, -5.0, 1.0]);
-        let b = Poly(vec![12.0, 12.0]);
-        assert_eq!(&a / &b, (Poly(vec![-0.5, 1.0/12.0]), Poly(vec![0.0, 0.0])));
+        let a = Poly::new(vec![-6.0, -5.0, 1.0]);
+        let b = Poly::new(vec![12.0, 12.0]);
+        assert_eq!(&a / &b, (Poly::new(vec![-0.5, 1.0/12.0]), Poly::new(vec![0.0, 0.0])));
     }
 
     #[test]
     fn div_less() {
-        let a = Poly(vec![12.0, 12.0]);
-        let b = Poly(vec![-6.0, -5.0, 1.0]);
-        assert_eq!(&a / &b, (Poly(vec![0.0]), a));
+        let a = Poly::new(vec![12.0, 12.0]);
+        let b = Poly::new(vec![-6.0, -5.0, 1.0]);
+        assert_eq!(&a / &b, (Poly::new(vec![0.0]), a));
     }
 
     #[test]
     fn mul_test() {
-        let a = Poly(vec![1.0, 2.0, 3.0]);
-        let b = Poly(vec![1.0, 2.0]);
-        assert_eq!(&a * &b, Poly(vec![1.0, 4.0, 7.0, 6.0]));
+        let a = Poly::new(vec![1.0, 2.0, 3.0]);
+        let b = Poly::new(vec![1.0, 2.0]);
+        assert_eq!(&a * &b, Poly::new(vec![1.0, 4.0, 7.0, 6.0]));
     }
 
     #[test]
     fn add_test() {
-        let a = Poly(vec![1.0]);
-        let b = Poly(vec![0.0, 0.0, 0.0, 1.0]);
-        assert_eq!(&a + &b, Poly(vec![1.0, 0.0, 0.0, 1.0]));
+        let a = Poly::new(vec![1.0]);
+        let b = Poly::new(vec![0.0, 0.0, 0.0, 1.0]);
+        assert_eq!(&a + &b, Poly::new(vec![1.0, 0.0, 0.0, 1.0]));
     }
 
     #[test]
     fn sub_test() {
-        let a = Poly(vec![1.0, 2.0, 3.0]);
-        let b = Poly(vec![1.0, 1.0, 1.0]);
-        assert_eq!(&a - &b, Poly(vec![0.0, 1.0, 2.0]));
+        let a = Poly::new(vec![1.0, 2.0, 3.0]);
+        let b = Poly::new(vec![1.0, 1.0, 1.0]);
+        assert_eq!(&a - &b, Poly::new(vec![0.0, 1.0, 2.0]));
     }
 
     #[test]
     fn poly_is_zero() {
-        let p = Poly(vec![0.0; 5]);
+        let p = Poly::new(vec![0.0; 5]);
         assert_eq!(p.is_zero(), true);
     }
 
     #[test]
     fn poly_is_not_zero() {
-        let mut p = vec![0.0; 5];
-        p[2] = 8.0;
-        assert_eq!(Poly(p).is_zero(), false);
+        let p = Poly::mono(5, 8.0);
+        assert_eq!(p.is_zero(), false);
     }
 
     #[test]
     fn degree_is_five() {
-        let mut p = vec![0.0; 6];
-        p[5] = 2.0;
-        assert_eq!(Poly(p).degree(), 5);
+        let p = Poly::mono(5, 2.0);
+        assert_eq!(p.degree(), 5);
     }
 
     #[test]
     fn degree_is_zero() {
-        let p = Poly(vec![0.0; 6]);
+        let p = Poly::new(vec![0.0; 6]);
         assert_eq!(p.degree(), 0);
     }
 
     #[test]
     fn gcd_test() {
-        let a = Poly(vec![2.0, -8.0, 8.0]);
-        let b = Poly(vec![-1.0, 4.0, -1.0]);
-        assert_eq!(gcd(&a, &b), Poly(vec![-0.0625, 0.0]));
+        let a = Poly::new(vec![2.0, -8.0, 8.0]);
+        let b = Poly::new(vec![-1.0, 4.0, -1.0]);
+        assert_eq!(gcd(&a, &b), Poly::new(vec![-0.0625, 0.0]));
     }
 }