From 702eab158345bfde6931cc641fc59401b88d2b98 Mon Sep 17 00:00:00 2001
From: wborgeaud <williamborgeaud@gmail.com>
Date: Thu, 12 Aug 2021 16:03:13 +0200
Subject: [PATCH] Add `wide_arithmetic`

---
 src/gadgets/arithmetic_extension.rs | 18 +++++++++----
 src/plonk/vanishing_poly.rs         | 39 +++--------------------------
 2 files changed, 16 insertions(+), 41 deletions(-)

diff --git a/src/gadgets/arithmetic_extension.rs b/src/gadgets/arithmetic_extension.rs
index 03395211..8b7c11e3 100644
--- a/src/gadgets/arithmetic_extension.rs
+++ b/src/gadgets/arithmetic_extension.rs
@@ -152,6 +152,18 @@ impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         None
     }
 
+    /// Returns `a*b + c*d + e`.
+    pub fn wide_arithmetic_extension(
+        &mut self,
+        a: ExtensionTarget<D>,
+        b: ExtensionTarget<D>,
+        c: ExtensionTarget<D>,
+        d: ExtensionTarget<D>,
+        e: ExtensionTarget<D>,
+    ) -> ExtensionTarget<D> {
+        self.inner_product_extension(F::ONE, e, vec![(a, b), (c, d)])
+    }
+
     /// Returns `sum_{(a,b) in vecs} constant * a * b`.
     pub fn inner_product_extension(
         &mut self,
@@ -230,11 +242,7 @@ impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         c: ExtensionTarget<D>,
     ) -> ExtensionTarget<D> {
         let one = self.one_extension();
-        let gate = self.num_gates();
-        let first_out =
-            ExtensionTarget::from_range(gate, ArithmeticExtensionGate::<D>::wires_first_output());
-        self.double_arithmetic_extension(F::ONE, F::ONE, one, a, b, one, c, first_out)
-            .1
+        self.wide_arithmetic_extension(one, a, one, b, c)
     }
 
     /// Add `n` `ExtensionTarget`s with `n/2` `ArithmeticExtensionGate`s.
diff --git a/src/plonk/vanishing_poly.rs b/src/plonk/vanishing_poly.rs
index 30101d3f..a0e00395 100644
--- a/src/plonk/vanishing_poly.rs
+++ b/src/plonk/vanishing_poly.rs
@@ -328,50 +328,17 @@ pub(crate) fn eval_vanishing_poly_recursively<F: Extendable<D>, const D: usize>(
                 let wire_value = vars.local_wires[j];
                 let beta_ext = builder.convert_to_ext(betas[i]);
                 let gamma_ext = builder.convert_to_ext(gammas[i]);
-                let gate = builder.num_gates();
-                let first_out = ExtensionTarget::from_range(
-                    gate,
-                    ArithmeticExtensionGate::<D>::wires_first_output(),
-                );
-                // `beta * s_ids[j] + wire_value + gamma`
-                builder
-                    .double_arithmetic_extension(
-                        F::ONE,
-                        F::ONE,
-                        beta_ext,
-                        s_ids[j],
-                        wire_value,
-                        one,
-                        first_out,
-                        gamma_ext,
-                    )
-                    .1
+                // `beta * s_id + wire_value + gamma`
+                builder.wide_arithmetic_extension(beta_ext, s_ids[j], one, wire_value, gamma_ext)
             })
             .collect::<Vec<_>>();
         let denominator_values = (0..common_data.config.num_routed_wires)
             .map(|j| {
                 let wire_value = vars.local_wires[j];
-                let s_sigma = s_sigmas[j];
                 let beta_ext = builder.convert_to_ext(betas[i]);
                 let gamma_ext = builder.convert_to_ext(gammas[i]);
-                let gate = builder.num_gates();
-                let first_out = ExtensionTarget::from_range(
-                    gate,
-                    ArithmeticExtensionGate::<D>::wires_first_output(),
-                );
                 // `beta * s_sigma + wire_value + gamma`
-                builder
-                    .double_arithmetic_extension(
-                        F::ONE,
-                        F::ONE,
-                        beta_ext,
-                        s_sigma,
-                        wire_value,
-                        one,
-                        first_out,
-                        gamma_ext,
-                    )
-                    .1
+                builder.wide_arithmetic_extension(beta_ext, s_sigmas[j], one, wire_value, gamma_ext)
             })
             .collect::<Vec<_>>();
         let quotient_values = (0..common_data.config.num_routed_wires)