From 6391912bc4fdb9bb67c829c588249ecc8405f595 Mon Sep 17 00:00:00 2001
From: Alivecow <mail@ta-lotz.de>
Date: Fri, 22 Nov 2024 15:47:59 +0100
Subject: [PATCH] feat: Add and improve poly monic function with testcases

Make a polynomial monic by dividing all field elements with the leading
element
---
 src/utils/poly.rs | 45 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

diff --git a/src/utils/poly.rs b/src/utils/poly.rs
index bb05366..e624361 100644
--- a/src/utils/poly.rs
+++ b/src/utils/poly.rs
@@ -219,6 +219,22 @@ impl Polynomial {
             *fieldelement = fieldelement.clone() / divident.clone();
         }
 
+        while !self.polynomial.is_empty()
+            && self
+                .polynomial
+                .last()
+                .unwrap()
+                .as_ref()
+                .iter()
+                .all(|&x| x == 0)
+        {
+            self.polynomial.pop();
+        }
+
+        if self.is_empty() {
+            self = Polynomial::new(vec![FieldElement::new(vec![0; 16])]);
+        }
+
         self
     }
 }
@@ -1047,7 +1063,6 @@ mod tests {
         let result = element1.pow_mod(10000000, modulus);
 
         assert!(!result.is_zero())
-        //assert_eq!(BASE64_STANDARD.encode(product), "MoAAAAAAAAAAAAAAAAAAAA==");
     }
 
     #[test]
@@ -1069,6 +1084,32 @@ mod tests {
         let result = element1.monic();
 
         assert_eq!(json!(result.to_c_array()), expected);
-        //assert_eq!(BASE64_STANDARD.encode(product), "MoAAAAAAAAAAAAAAAAAAAA==");
+    }
+
+    #[test]
+    fn test_poly_monic_poly_zero() {
+        let json1 = json!(["AAAAAAAAAAAAAAAAAAAAAA=="]);
+        let expected = json!(["AAAAAAAAAAAAAAAAAAAAAA=="]);
+        let element1: Polynomial = Polynomial::from_c_array(&json1);
+
+        let result = element1.monic();
+
+        assert_eq!(json!(result.to_c_array()), expected);
+    }
+
+    #[test]
+    fn test_poly_monic_poly_multiple_zero() {
+        let json1 = json!([
+            "AAAAAAAAAAAAAAAAAAAAAA==",
+            "AAAAAAAAAAAAAAAAAAAAAA==",
+            "AAAAAAAAAAAAAAAAAAAAAA==",
+            "AAAAAAAAAAAAAAAAAAAAAA=="
+        ]);
+        let expected = json!(["AAAAAAAAAAAAAAAAAAAAAA=="]);
+        let element1: Polynomial = Polynomial::from_c_array(&json1);
+
+        let result = element1.monic();
+
+        assert_eq!(json!(result.to_c_array()), expected);
     }
 }