Add GroupMap::composition for debugging

Author: sebastiencs

groupmap/src/lib.rs

@@ -26,6 +26,8 @@ pub trait GroupMap<F> {
     fn setup() -> Self;
     fn to_group(&self, u: F) -> (F, F);
     fn batch_to_group_x(&self, ts: Vec<F>) -> Vec<[F; 3]>;
+    /// For debug only
+    fn composition(&self) -> Vec<F>;
 }
 
 #[derive(Clone, Copy)]
@@ -127,6 +129,25 @@ fn get_xy<G: SWModelParameters>(
 }
 
 impl<G: SWModelParameters> GroupMap<G::BaseField> for BWParameters<G> {
+    /// For debug only
+    fn composition(&self) -> Vec<G::BaseField> {
+        let Self {
+            u,
+            fu,
+            sqrt_neg_three_u_squared_minus_u_over_2,
+            sqrt_neg_three_u_squared,
+            inv_three_u_squared,
+        } = self;
+
+        vec![
+            *u,
+            *fu,
+            *sqrt_neg_three_u_squared_minus_u_over_2,
+            *sqrt_neg_three_u_squared,
+            *inv_three_u_squared,
+        ]
+    }
+
     fn setup() -> Self {
         assert!(G::COEFF_A.is_zero());