Address third round of code review feedback

- Rename test to test_normalize_near_zero_vector_normalizes_correctly
- Simplify singular value sqrt to [val, 0.0].max for uniform handling
- Preserve sign relationship in content_node divisor fallback

Author: cardmagic

lib/classifier/extensions/vector.rb

@@ -102,7 +102,7 @@ def SV_decomp(max_sweeps = 20)
     q_rotation_matrix.row_size.times do |r|
       # Guard against negative values due to floating point errors
       val = q_rotation_matrix[r, r].to_f
-      singular_values << Math.sqrt(val < -Vector::EPSILON ? 0.0 : val.abs)
+      singular_values << Math.sqrt([val, 0.0].max)
     end
 
     # Replace near-zero singular values with EPSILON to prevent division by zero

lib/classifier/lsi/content_node.rb

@@ -61,8 +61,13 @@ def raw_vector_with(word_list)
           weighted_total += val unless val.nan?
         end
 
-        # Guard against division by zero - use small epsilon if weighted_total is zero
-        divisor = weighted_total.abs < Vector::EPSILON ? -Vector::EPSILON : -weighted_total
+        # Guard against division by zero - use small epsilon if weighted_total is near zero,
+        # while preserving the sign relationship with -weighted_total.
+        divisor = if weighted_total.abs < Vector::EPSILON
+                    weighted_total.negative? ? Vector::EPSILON : -Vector::EPSILON
+                  else
+                    -weighted_total
+                  end
         vec = vec.collect { |val| Math.log(val + 1) / divisor }
       end
 

test/extensions/word_hash_test.rb

@@ -125,7 +125,7 @@ def test_normalize_zero_vector_returns_zero_vector
     assert_in_delta 0.0, normalized[2], 0.001
   end
 
-  def test_normalize_near_zero_vector_returns_unit_vector
+  def test_normalize_near_zero_vector_normalizes_correctly
     # Near-zero vectors should still normalize to unit vectors
     # Only actual zero vectors return zero
     vec = Vector[1e-15, 1e-15, 1e-15]