wip on plaintext ring packing

math/src/ring/impl_u64/packing.rs

@@ -0,0 +1,60 @@
+use std::collections::HashMap;
+use crate::poly::Poly;
+use crate::ring::Ring;
+use crate::modulus::ONCE;
+
+
+impl Ring<u64>{
+
+    // Generates a vector storing {X^{2^0}, X^{2^1}, .., X^{2^log_n}}.
+    pub fn gen_x_pow_2<const NTT: bool, const INV: bool>(&self, log_n: usize) -> Vec<Poly<u64>>{
+        let mut x_pow: Vec<Poly<u64>> = Vec::<Poly<u64>>::with_capacity(log_n);
+
+        (0..log_n).for_each(|i|{
+            let mut idx: usize = 1<<i;
+
+            if INV{
+                idx = self.n() - idx;
+            }
+
+            x_pow.push(self.new_poly());
+
+            if i == 0{
+                x_pow[i].0[idx] = self.modulus.montgomery.one();
+                self.ntt_inplace::<false>(&mut x_pow[i]);
+            }else{
+                let (left, right) = x_pow.split_at_mut(i);
+                self.a_mul_b_montgomery_into_c::<ONCE>(&left[i-1], &left[i-1], &mut right[0]);
+            }
+        });
+
+        if INV{
+            self.a_neg_into_a::<1, ONCE>(&mut x_pow[0]);
+        }
+
+        if !NTT{
+            x_pow.iter_mut().for_each(|x| self.intt_inplace::<false>(x));
+        }
+
+        x_pow
+    }
+
+    pub fn pack<const ZEROGARBAGE: bool, const NTT: bool>(&self, polys: HashMap<Poly<u64>, usize>, log_gap: usize) -> Poly<u64>{
+        
+        let log_n = self.log_n();
+        let log_start = log_n - log_gap;
+        let log_end = log_n;
+
+        /* 
+        if !ZEROGARBAGE{
+            if gap > 0 {
+                log_end -= log_gap;
+            }
+        }
+        */
+        
+        let n_inv = self.modulus.inv(1<<(log_end - log_start));
+
+        Poly::<u64>::default()
+    }
+}