From 9423fa31dfacd0e877ee02c26a0a09d99a5eee46 Mon Sep 17 00:00:00 2001
From: itscomputers <its_computers@protonmail.com>
Date: Thu, 25 Jul 2019 21:36:11 -0600
Subject: [PATCH] initial bad version of polynomial gcd

---
 numth/types/polynomial.py      | 48 +++++++++++++++++-----------------
 tests/test_types_polynomial.py | 20 +++++++-------
 2 files changed, 34 insertions(+), 34 deletions(-)

diff --git a/numth/types/polynomial.py b/numth/types/polynomial.py
index ec16772..20a29a8 100644
--- a/numth/types/polynomial.py
+++ b/numth/types/polynomial.py
@@ -257,36 +257,36 @@ def derivative(self, order=None):
 
     #-------------------------
 
-#   def mod_gcd(self, other, modulus):
-#       if self == other == Polynomial({0: 0}):
-#           raise ValueError('gcd(0, 0) is undefined')
+    def mod_gcd(self, other, modulus):
+        if self == other == Polynomial({0: 0}):
+            raise ValueError('gcd(0, 0) is undefined')
 
-#       if self.degree == other.degree == 1:
-#           s_m = self.coeffs[0] % modulus
-#           o_m = other.coeffs[0] % modulus
-#           return gcd(s_m, o_m) % modulus
+        if self.degree == other.degree == 1:
+            s_m = self.coeffs[0] % modulus
+            o_m = other.coeffs[0] % modulus
+            return gcd(s_m, o_m) % modulus
 
-#       a, b = self % modulus, other % modulus
-#       while b.degree >= 0:
-#           a, b = b, (a % b) % modulus
+        a, b = self % modulus, other % modulus
+        while b.degree >= 0:
+            a, b = b, (a % b) % modulus
 
-#       return (mod_inverse(a.leading_coeff, modulus) * a) % modulus
+        return (mod_inverse(a.leading_coeff, modulus) * a) % modulus
     
     #-------------------------
     
-#   use subresultant polynomials to compute
-#   def gcd(self, other):
-#       if self == other == polyn('0'):
-#           raise ValueError('gcd(0, 0) is undefined')
-#       
-#       if self.degree == other.degree == 1:
-#           return gcd(self.coeffs[0], other.coeffs[0])
-
-#       a, b = self.to_integer_polyn(), other.to_integer_polyn()
-#       while b.degree >= 0:
-#           a, b = b, a % b
-
-#       return a.canonical() / gcd(*a.coeffs.values())
+    use subresultant polynomials to compute
+    def gcd(self, other):
+        if self == other == polyn('0'):
+            raise ValueError('gcd(0, 0) is undefined')
+        
+        if self.degree == other.degree == 1:
+            return gcd(self.coeffs[0], other.coeffs[0])
+
+        a, b = self.to_integer_polyn(), other.to_integer_polyn()
+        while b.degree >= 0:
+            a, b = b, a % b
+
+        return a.canonical() / gcd(*a.coeffs.values())
 
 #===========================================================
 
diff --git a/tests/test_types_polynomial.py b/tests/test_types_polynomial.py
index f93edb4..a31e61f 100644
--- a/tests/test_types_polynomial.py
+++ b/tests/test_types_polynomial.py
@@ -390,16 +390,16 @@ def test_mod_eval(e1, c1, e2, c2, val, mod):
 
 #-----------------------------
 
-#   @given(*coords(4, coeff_min=1))
-#   def test_mod_gcd(e1, c1, e2, c2, e3, c3, e4, c4):
-#       modulus = choice([2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47])
-#       assume( are_distinct(e1, e2) and are_distinct(e3, e4) )
-#       p1 = make(e1, c1, e2, c2) % modulus
-#       p2 = make(e3, c3, e4, c4) % modulus
-#       d = p1.mod_gcd(p2, modulus)
-#       assert( d == p2.mod_gcd(p1, modulus) )
-#       assert( p1 % d % modulus == p2 % d % modulus == polyn('0') )
-#       assert( (p1 // d).mod_gcd(p2 // d, modulus) == polyn('1') )
+    @given(*coords(4, coeff_min=1))
+    def test_mod_gcd(e1, c1, e2, c2, e3, c3, e4, c4):
+        modulus = choice([2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47])
+        assume( are_distinct(e1, e2) and are_distinct(e3, e4) )
+        p1 = make(e1, c1, e2, c2) % modulus
+        p2 = make(e3, c3, e4, c4) % modulus
+        d = p1.mod_gcd(p2, modulus)
+        assert( d == p2.mod_gcd(p1, modulus) )
+        assert( p1 % d % modulus == p2 % d % modulus == polyn('0') )
+        assert( (p1 // d).mod_gcd(p2 // d, modulus) == polyn('1') )
 
 #=============================