fixed automorphism for ring and added test

math/tests/automorphism.rs

@@ -0,0 +1,53 @@
+use itertools::izip;
+use math::poly::Poly;
+use math::ring::Ring;
+
+#[test]
+fn automorphism_u64() {
+    let n: usize = 1 << 4;
+    let nth_root: usize = n << 1;
+    let q_base: u64 = 65537u64;
+    let q_power: usize = 1usize;
+    let ring: Ring<u64> = Ring::new(n, q_base, q_power);
+
+    sub_test("test_automorphism_u64::<NTT:false>", || {
+        test_automorphism_u64::<false>(&ring, nth_root)
+    });
+    sub_test("test_automorphism_u64::<NTT:true>", || {
+        test_automorphism_u64::<true>(&ring, nth_root)
+    });
+}
+
+fn sub_test<F: FnOnce()>(name: &str, f: F) {
+    println!("Running {}", name);
+    f();
+}
+
+fn test_automorphism_u64<const NTT: bool>(ring: &Ring<u64>, nth_root: usize) {
+    let n: usize = ring.n();
+    let q: u64 = ring.modulus.q;
+
+    let mut p0: Poly<u64> = ring.new_poly();
+    let mut p1: Poly<u64> = ring.new_poly();
+
+    for i in 0..p0.n() {
+        p0.0[i] = i as u64
+    }
+
+    if NTT {
+        ring.ntt_inplace::<false>(&mut p0);
+    }
+
+    ring.automorphism::<NTT>(&p0, 2 * n - 1, nth_root, &mut p1);
+
+    if NTT {
+        ring.intt_inplace::<false>(&mut p1);
+    }
+
+    p0.0[0] = 0;
+    for i in 1..p0.n() {
+        p0.0[i] = q - (n - i) as u64
+    }
+
+    izip!(p0.0, p1.0).for_each(|(a, b)| assert_eq!(a, b));
+}