From 468a7523a296a9792232953e9cfcb1f01eb82b40 Mon Sep 17 00:00:00 2001
From: Ethan-000 <s2026080@ed.ac.uk>
Date: Thu, 18 May 2023 16:49:53 +0100
Subject: [PATCH] add a constructor (#164)

* add a constructor

* add more comment

* fix as review

* remove clone

* remove

* no need to use new variable

* change comment

* fix clippy

* rename to from_parts

* remove n declaration
---
 halo2_proofs/src/poly/kzg/commitment.rs | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/halo2_proofs/src/poly/kzg/commitment.rs b/halo2_proofs/src/poly/kzg/commitment.rs
index a2886a016c..51f0c660d0 100644
--- a/halo2_proofs/src/poly/kzg/commitment.rs
+++ b/halo2_proofs/src/poly/kzg/commitment.rs
@@ -132,6 +132,30 @@ where
         }
     }
 
+    /// Initializes parameters for the curve through existing parameters
+    /// k, g, g_lagrange (optional), g2, s_g2
+    pub fn from_parts(
+        &self,
+        k: u32,
+        g: Vec<E::G1Affine>,
+        g_lagrange: Option<Vec<E::G1Affine>>,
+        g2: E::G2Affine,
+        s_g2: E::G2Affine,
+    ) -> Self {
+        Self {
+            k,
+            n: 1 << k,
+            g_lagrange: if let Some(g_l) = g_lagrange {
+                g_l
+            } else {
+                g_to_lagrange(g.iter().map(PrimeCurveAffine::to_curve).collect(), k)
+            },
+            g,
+            g2,
+            s_g2,
+        }
+    }
+
     /// Returns gernerator on G2
     pub fn g2(&self) -> E::G2Affine {
         self.g2