refactor: clean up compute_next_accumulator (#5516)

Partially addresses AztecProtocol/barretenberg#881. Cuts down on accumulator_update_round time by 300ms! ``` -------------------------------------------------------------------------------- Benchmark Time CPU Iterations UserCounters... -------------------------------------------------------------------------------- ClientIVCBench/Full/6 22272 ms 17339 ms 1 Decider::construct_proof=1 Decider::construct_proof(t)=752.81M ECCVMComposer::compute_commitment_key=1 ECCVMComposer::compute_commitment_key(t)=3.74397M ECCVMComposer::compute_witness=1 ECCVMComposer::compute_witness(t)=131.409M ECCVMComposer::create_prover=1 ECCVMComposer::create_prover(t)=151.452M ECCVMComposer::create_proving_key=1 ECCVMComposer::create_proving_key(t)=16.0709M ECCVMProver::construct_proof=1 ECCVMProver::construct_proof(t)=1.76787G Goblin::merge=11 Goblin::merge(t)=144.332M GoblinTranslatorCircuitBuilder::constructor=1 GoblinTranslatorCircuitBuilder::constructor(t)=58.9093M GoblinTranslatorProver=1 GoblinTranslatorProver(t)=164.575M GoblinTranslatorProver::construct_proof=1 GoblinTranslatorProver::construct_proof(t)=958.34M ProtoGalaxyProver_::accumulator_update_round=10 ProtoGalaxyProver_::accumulator_update_round(t)=292.705M ProtoGalaxyProver_::combiner_quotient_round=10 ProtoGalaxyProver_::combiner_quotient_round(t)=5.96917G ProtoGalaxyProver_::perturbator_round=10 ProtoGalaxyProver_::perturbator_round(t)=1.30937G ProtoGalaxyProver_::preparation_round=10 ProtoGalaxyProver_::preparation_round(t)=4.18574G ProtogalaxyProver::fold_instances=10 ProtogalaxyProver::fold_instances(t)=11.757G ProverInstance(Circuit&)=11 ProverInstance(Circuit&)(t)=1.99482G batch_mul_with_endomorphism=30 batch_mul_with_endomorphism(t)=566.111M commit=426 commit(t)=4.0365G compute_combiner=10 compute_combiner(t)=5.96705G compute_perturbator=9 compute_perturbator(t)=1.30905G compute_univariate=48 compute_univariate(t)=1.42119G construct_circuits=6 construct_circuits(t)=4.49152G Benchmarking lock deleted. client_ivc_bench.json 100% 3992 123.3KB/s 00:00 function ms % sum construct_circuits(t) 4492 20.40% ProverInstance(Circuit&)(t) 1995 9.06% ProtogalaxyProver::fold_instances(t) 11757 53.40% Decider::construct_proof(t) 753 3.42% ECCVMComposer::create_prover(t) 151 0.69% ECCVMProver::construct_proof(t) 1768 8.03% GoblinTranslatorProver::construct_proof(t) 958 4.35% Goblin::merge(t) 144 0.66% Total time accounted for: 22018ms/22272ms = 98.86% Major contributors: function ms % sum commit(t) 4037 18.33% compute_combiner(t) 5967 27.10% compute_perturbator(t) 1309 5.95% compute_univariate(t) 1421 6.45% Breakdown of ProtogalaxyProver::fold_instances: ProtoGalaxyProver_::preparation_round(t) 4186 35.60% ProtoGalaxyProver_::perturbator_round(t) 1309 11.14% ProtoGalaxyProver_::combiner_quotient_round(t) 5969 50.77% ProtoGalaxyProver_::accumulator_update_round(t) 293 2.49% ``` Please read [contributing guidelines](CONTRIBUTING.md) and remove this line.
AztecProtocol · Apr 1, 2024 · f9be2f2 · f9be2f2
1 parent a0720ff
commit f9be2f2
Showing 1 changed file with 16 additions and 16 deletions.
diff --git a/barretenberg/cpp/src/barretenberg/protogalaxy/protogalaxy_prover.cpp b/barretenberg/cpp/src/barretenberg/protogalaxy/protogalaxy_prover.cpp
@@ -50,9 +50,8 @@ std::shared_ptr<typename ProverInstances::Instance> ProtoGalaxyProver_<ProverIns
     std::vector<FF> lagranges{ FF(1) - challenge, challenge };
 
     // TODO(https://github.com/AztecProtocol/barretenberg/issues/881): bad pattern
-    auto next_accumulator = std::make_shared<Instance>();
+    auto next_accumulator = std::move(instances[0]);
     next_accumulator->is_accumulator = true;
-    next_accumulator->proving_key = instances[0]->proving_key;
 
     // Compute the next target sum and send the next folding parameters to the verifier
     FF next_target_sum =
@@ -61,15 +60,19 @@ std::shared_ptr<typename ProverInstances::Instance> ProtoGalaxyProver_<ProverIns
     next_accumulator->target_sum = next_target_sum;
     next_accumulator->gate_challenges = instances.next_gate_challenges;
 
-    // Initialize prover polynomials
-    ProvingKey acc_proving_key_polys;
-    for (auto& polynomial : acc_proving_key_polys.get_all()) {
-        polynomial = typename Flavor::Polynomial(instances[0]->proving_key->circuit_size);
-    }
+    // Initialize accumulator proving key polynomials
+    auto accumulator_polys = next_accumulator->proving_key->get_all();
+    run_loop_in_parallel(Flavor::NUM_FOLDED_ENTITIES, [&](size_t start_idx, size_t end_idx) {
+        for (size_t poly_idx = start_idx; poly_idx < end_idx; poly_idx++) {
+            auto& acc_poly = accumulator_polys[poly_idx];
+            for (auto& acc_el : acc_poly) {
+                acc_el = acc_el * lagranges[0];
+            }
+        }
+    });
 
-    // Fold the prover key polynomials
-    for (size_t inst_idx = 0; inst_idx < ProverInstances::NUM; inst_idx++) {
-        auto accumulator_polys = acc_proving_key_polys.get_all();
+    // Fold the proving key polynomials
+    for (size_t inst_idx = 1; inst_idx < ProverInstances::NUM; inst_idx++) {
         auto input_polys = instances[inst_idx]->proving_key->get_all();
         run_loop_in_parallel(Flavor::NUM_FOLDED_ENTITIES, [&](size_t start_idx, size_t end_idx) {
             for (size_t poly_idx = start_idx; poly_idx < end_idx; poly_idx++) {
@@ -81,20 +84,17 @@ std::shared_ptr<typename ProverInstances::Instance> ProtoGalaxyProver_<ProverIns
             }
         });
     }
-    for (auto [next_acc_poly, acc_poly] :
-         zip_view(next_accumulator->proving_key->get_all(), acc_proving_key_polys.get_all())) {
-        next_acc_poly = std::move(acc_poly);
-    }
 
     // Fold public data ϕ from all instances to produce ϕ* and add it to the transcript. As part of the folding
     // verification, the verifier will produce ϕ* as well and check it against what was sent by the prover.
 
     // Fold the public inputs and send to the verifier
-    next_accumulator->proving_key->public_inputs = std::vector<FF>(instances[0]->proving_key->public_inputs.size(), 0);
     size_t el_idx = 0;
     for (auto& el : next_accumulator->proving_key->public_inputs) {
+        el = el * lagranges[0];
         size_t inst = 0;
-        for (auto& instance : instances) {
+        for (size_t inst_idx = 1; inst_idx < ProverInstances::NUM; inst_idx++) {
+            auto& instance = instances[inst_idx];
             // TODO(https://github.com/AztecProtocol/barretenberg/issues/830)
             if (instance->proving_key->num_public_inputs >= next_accumulator->proving_key->num_public_inputs) {
                 el += instance->proving_key->public_inputs[el_idx] * lagranges[inst];