Data commit

Task/Jacobi-symbol/Sidef/jacobi-symbol.sidef

@@ -0,0 +1,20 @@
+func jacobi(n, k) {
+
+    assert(k > 0,    "#{k} must be positive")
+    assert(k.is_odd, "#{k} must be odd")
+
+    var t = 1
+    while (n %= k) {
+        var v = n.valuation(2)
+        t *= (-1)**v if (k%8 ~~ [3,5])
+        n >>= v
+        (n,k) = (k,n)
+        t = -t if ([n%4, k%4] == [3,3])
+    }
+
+    k==1 ? t : 0
+}
+
+for n in (0..50), k in (0..50) {
+    assert_eq(jacobi(n, 2*k + 1), kronecker(n, 2*k + 1))
+}