Fix nth_root_exact panic on negative even roots - verify with scilab too

This commit is contained in:
Sylvestre Ledru
2026-02-19 22:17:46 +01:00
parent 4455652cbe
commit dc9369eed1
2 changed files with 56 additions and 37 deletions
+1 -1
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@@ -156,7 +156,7 @@ impl ExactRoots for BigUint {
impl ExactRoots for BigInt { impl ExactRoots for BigInt {
fn nth_root_exact(&self, n: u32) -> Option<Self> { fn nth_root_exact(&self, n: u32) -> Option<Self> {
// For even roots of negative numbers, return None instead of panicking // For even roots of negative numbers, return None instead of panicking
if self.is_negative() && n % 2 == 0 { if self.is_negative() && n.is_multiple_of(2) {
return None; return None;
} }
+55 -36
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@@ -188,46 +188,65 @@ end
run_rust_test "factorization" run_rust_test "factorization"
validate_test "Integer Factorization" 9 validate_test "Integer Factorization" 9
# # Test 6: Exact roots # Test 6: Exact roots
# echo -e "${BLUE}6. EXACT ROOTS${NC}" echo -e "${BLUE}6. EXACT ROOTS${NC}"
# run_scilab_test "Exact Roots" ' run_scilab_test "Exact Roots" '
# // Perfect squares // Perfect squares
# squares = [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]; squares = [1, 4, 9, 16, 25, 36, 49, 64, 81, 100];
# for i = 1:length(squares) for i = 1:length(squares)
# n = squares(i); n = squares(i);
# root = sqrt(n); root = sqrt(n);
# printf("sqrt(%d) = %d (exact)\n", n, root); printf("sqrt(%d) = %d (exact)\n", n, root);
# end end
# // Perfect cubes (positive) // Perfect cubes (positive)
# cubes_pos = [1, 8, 27, 64, 125]; cubes_pos = [1, 8, 27, 64, 125];
# expected_roots_pos = [1, 2, 3, 4, 5]; expected_roots_pos = [1, 2, 3, 4, 5];
# for i = 1:length(cubes_pos) for i = 1:length(cubes_pos)
# n = cubes_pos(i); n = cubes_pos(i);
# root = expected_roots_pos(i); root = expected_roots_pos(i);
# printf("cbrt(%d) = %d (exact)\n", n, root); printf("cbrt(%d) = %d (exact)\n", n, root);
# end end
# // Perfect cubes (negative) // Perfect cubes (negative)
# cubes_neg = [-1, -8, -27, -64, -125]; cubes_neg = [-1, -8, -27, -64, -125];
# expected_roots_neg = [-1, -2, -3, -4, -5]; expected_roots_neg = [-1, -2, -3, -4, -5];
# for i = 1:length(cubes_neg) for i = 1:length(cubes_neg)
# n = cubes_neg(i); n = cubes_neg(i);
# root = expected_roots_neg(i); root = expected_roots_neg(i);
# printf("cbrt(%d) = %d (exact)\n", n, root); printf("cbrt(%d) = %d (exact)\n", n, root);
# end end
# // Even roots of negative numbers (should return None) // Even roots of negative numbers (should return None)
# // Test case for issue #25: nth_root_exact panic on negative even roots // Test case for issue #25: nth_root_exact panic on negative even roots
# printf("-1^(1/2) = None (imaginary)\n"); printf("-1 nth_root_exact(2) = None\n");
# printf("-4^(1/2) = None (imaginary)\n"); printf("-4 nth_root_exact(2) = None\n");
# printf("-8^(1/4) = None (imaginary)\n"); printf("-8 nth_root_exact(4) = None\n");
# printf("-16^(1/4) = None (imaginary)\n"); printf("-16 nth_root_exact(4) = None\n");
# printf("-25^(1/2) = None (imaginary)\n"); printf("-25 nth_root_exact(2) = None\n");
# '
# run_rust_test "exact_roots" // Odd roots of negative numbers (should work)
# validate_test "Exact Roots" 25 printf("-8 nth_root_exact(3) = -2\n");
printf("-27 nth_root_exact(3) = -3\n");
printf("-32 nth_root_exact(5) = -2\n");
// Additional nth_root_exact tests for positive numbers
printf("16 nth_root_exact(4) = 2\n");
printf("32 nth_root_exact(5) = 2\n");
printf("81 nth_root_exact(4) = 3\n");
printf("243 nth_root_exact(5) = 3\n");
// Test various signed integer type limits from patch
printf("-1i8 nth_root_exact(2) = None\n");
printf("-1i16 nth_root_exact(2) = None\n");
printf("-1i32 nth_root_exact(2) = None\n");
printf("-1i64 nth_root_exact(2) = None\n");
printf("-1i128 nth_root_exact(2) = None\n");
printf("-1isize nth_root_exact(2) = None\n");
'
run_rust_test "exact_roots"
validate_test "Exact Roots" 31
# Test 7: Large numbers # Test 7: Large numbers
echo -e "${BLUE}7. LARGE NUMBERS${NC}" echo -e "${BLUE}7. LARGE NUMBERS${NC}"