From 4ce243b22d06272652a09ea73859f1f812acf070 Mon Sep 17 00:00:00 2001
From: Neo <neotheprogramist@proton.me>
Date: Wed, 10 Jan 2024 12:02:48 +0100
Subject: [PATCH] domains impl

---
 src/common/consts.cairo |  2 ++
 src/domains.cairo       | 47 +++++++++++++++++++++++++++++++++++++++++
 src/lib.cairo           |  1 +
 src/stark.cairo         |  4 ++--
 4 files changed, 52 insertions(+), 2 deletions(-)
 create mode 100644 src/domains.cairo

diff --git a/src/common/consts.cairo b/src/common/consts.cairo
index 56ffa41ea..45399a7ea 100644
--- a/src/common/consts.cairo
+++ b/src/common/consts.cairo
@@ -1,5 +1,7 @@
 const STARK_PRIME: u256 =
     3618502788666131213697322783095070105623107215331596699973092056135872020481;
+const STARK_PRIME_MINUS_ONE: felt252 =
+    3618502788666131213697322783095070105623107215331596699973092056135872020480;
 const STARK_PRIME_MINUS_TWO: felt252 =
     3618502788666131213697322783095070105623107215331596699973092056135872020479;
 
diff --git a/src/domains.cairo b/src/domains.cairo
new file mode 100644
index 000000000..26247ed40
--- /dev/null
+++ b/src/domains.cairo
@@ -0,0 +1,47 @@
+use core::traits::Div;
+use cairo_verifier::{
+    common::{consts::{FIELD_GENERATOR, STARK_PRIME_MINUS_ONE}, math::{pow, mul_inverse}},
+    stark::StarkConfig,
+};
+
+// Information about the domains that are used in the stark proof.
+#[derive(Drop)]
+struct StarkDomains {
+    // Log2 of the evaluation domain size.
+    log_eval_domain_size: felt252,
+    // The evaluation domain size.
+    eval_domain_size: felt252,
+    // The generator of the evaluation domain (a primitive root of unity of order eval_domain_size).
+    eval_generator: felt252,
+    // Log2 of the trace domain size.
+    log_trace_domain_size: felt252,
+    // The trace domain size.
+    trace_domain_size: felt252,
+    // The generator of the trace domain (a primitive root of unity of order trace_domain_size).
+    trace_generator: felt252,
+}
+
+#[generate_trait]
+impl StarkDomainsImpl of StarkDomainsTrait {
+    fn new(stark_config: @StarkConfig) -> StarkDomains {
+        // Compute stark_domains.
+        let log_eval_domain_size = *stark_config.log_trace_domain_size + *stark_config.log_n_cosets;
+        let eval_domain_size = pow(2, log_eval_domain_size);
+        let eval_generator = pow(
+            FIELD_GENERATOR, STARK_PRIME_MINUS_ONE * mul_inverse(eval_domain_size)
+        );
+        let trace_domain_size = pow(2, *stark_config.log_trace_domain_size);
+        let trace_generator = pow(
+            FIELD_GENERATOR, STARK_PRIME_MINUS_ONE * mul_inverse(trace_domain_size)
+        );
+
+        StarkDomains {
+            log_eval_domain_size,
+            eval_domain_size,
+            eval_generator,
+            log_trace_domain_size: *stark_config.log_trace_domain_size,
+            trace_domain_size,
+            trace_generator,
+        }
+    }
+}
diff --git a/src/lib.cairo b/src/lib.cairo
index 101a3d8a5..f3ee6f613 100644
--- a/src/lib.cairo
+++ b/src/lib.cairo
@@ -2,6 +2,7 @@ mod air;
 mod channel;
 mod common;
 mod deserialization;
+mod domains;
 mod fri;
 mod oods;
 mod proof_of_work;
diff --git a/src/stark.cairo b/src/stark.cairo
index a65ad411d..61fd55aa2 100644
--- a/src/stark.cairo
+++ b/src/stark.cairo
@@ -7,7 +7,7 @@ use cairo_verifier::{
         config::{TracesConfig}, public_input::PublicInput,
         traces::{TracesUnsentCommitment, TracesDecommitment, TracesWitness}
     },
-    fri::{fri_config::FriConfig, fri::{FriUnsentCommitment, FriWitness}},
+    domains::StarkDomainsImpl, fri::{fri_config::FriConfig, fri::{FriUnsentCommitment, FriWitness}},
     table_commitment::{TableCommitmentConfig, TableCommitmentWitness, TableDecommitment},
     proof_of_work::{config::ProofOfWorkConfig, proof_of_work::ProofOfWorkUnsentCommitment},
 };
@@ -33,10 +33,10 @@ struct StarkProof {
 impl StarkProofImpl of StarkProofTrait {
     fn verify(self: @StarkProof) {
         self.config.validate(SECURITY_BITS);
+        let stark_domains = StarkDomainsImpl::new(self.config);
     }
 }
 
-
 #[derive(Drop, Copy)]
 struct StarkConfig {
     traces: TracesConfig,