Debug solveCongruence()

Author: WrathfulSpatula

FindAFactor/_find_a_factor.cpp

@@ -855,26 +855,24 @@ struct Factorizer {
   BigInteger solveCongruence(const std::vector<size_t>& solutionVec)
   {
     // Compute x and y
-    BigInteger x = 1;
+    BigInteger y = 1U;
     for (size_t idx : solutionVec) {
-      x *= smoothNumberKeys[idx];
+      y *= smoothNumberKeys[idx];
     }
     // If we square the result, it shouldn't ruin the fact
     // that the residue is a perfect square.
-    const BigInteger y = sqrt((x * x) % this->toFactor);
+    const BigInteger x = sqrt((y * y) % this->toFactor);
 
     // Check congruence of squares
     BigInteger factor = gcd(this->toFactor, x + y);
-    if ((factor != 1U) && (factor != this->toFactor)) {
+    if ((factor > 1U) && (factor < this->toFactor)) {
       return factor;
     }
 
-    if (x != y) {
-      // Try x - y as well
-      factor = gcd(this->toFactor, x - y);
-      if ((factor != 1U) && (factor != this->toFactor)) {
-        return factor;
-      }
+    // Try x - y as well
+    factor = gcd(this->toFactor, x - y);
+    if ((factor > 1U) && (factor < this->toFactor)) {
+      return factor;
     }
 
     // Failed to find a factor
@@ -987,7 +985,7 @@ struct Factorizer {
     GaussianEliminationResult result = gaussianElimination();
     for (size_t i = 0U; i < result.solutionColumns.size(); ++i) {
       const BigInteger factor = solveCongruence(findDependentRows(result, i));
-      if ((factor != 1U) && (factor != toFactor)) {
+      if ((factor > 1U) && (factor < toFactor)) {
         return factor;
       }
     }

pyproject.toml

@@ -8,7 +8,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "FindAFactor"
-version = "5.1.0"
+version = "5.1.1"
 requires-python = ">=3.8"
 description = "Find any nontrivial factor of a number"
 readme = {file = "README.txt", content-type = "text/markdown"}

setup.py

@@ -40,7 +40,7 @@ def build_extension(self, ext):
 
 setup(
     name='FindAFactor',
-    version='5.1.0',
+    version='5.1.1',
     author='Dan Strano',
     author_email='stranoj@gmail.com',
     description='Find any nontrivial factor of a number',