ecc_shiftable_init_relation.hpp

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// === AUDIT STATUS ===
// internal:    { status: not started, auditors: [], commit: }
// external_1:  { status: not started, auditors: [], commit: }
// external_2:  { status: not started, auditors: [], commit: }
// =====================
 
#pragma once
#include "barretenberg/relations/relation_types.hpp"
 
namespace bb {
 
template <typename FF_> class ECCVMShiftableInitRelationImpl {
  public:
    using FF = FF_;
 
    enum SubrelationIndex : size_t {
        // Load-bearing for soundness:
        //
        // Z_PERM_INIT and TRANSCRIPT_ACCUMULATOR_NOT_EMPTY_INIT were previously housed in
        // ECCVMSetRelation and ECCVMTranscriptRelation respectively; centralizing them here
        // keeps every direct `lagrange_first · col = 0` constraint in one place.
        Z_PERM_INIT = 0,
        TRANSCRIPT_ACCUMULATOR_NOT_EMPTY_INIT = 1,
        PRECOMPUTE_SELECT_INIT = 2,
        TRANSCRIPT_MUL_INIT = 3,
        TRANSCRIPT_PC_INIT = 4,
 
        // Defense-in-depth (values not currently read at lagrange_first, but pinning makes
        // the invariant explicit and robust to future relation changes):
        PRECOMPUTE_SCALAR_SUM_INIT = 5,
        PRECOMPUTE_DX_INIT = 6,
        PRECOMPUTE_DY_INIT = 7,
        PRECOMPUTE_TX_INIT = 8,
        PRECOMPUTE_TY_INIT = 9,
        MSM_TRANSITION_INIT = 10,
        MSM_ADD_INIT = 11,
        MSM_DOUBLE_INIT = 12,
        MSM_SKEW_INIT = 13,
        MSM_ACCUMULATOR_X_INIT = 14,
        MSM_ACCUMULATOR_Y_INIT = 15,
        MSM_COUNT_INIT = 16,
        MSM_ROUND_INIT = 17,
        MSM_ADD1_INIT = 18,
        MSM_PC_INIT = 19,
        TRANSCRIPT_MSM_COUNT_INIT = 20,
        NUM_SUBRELATIONS,
    };
 
    // Every subrelation is `lagrange_first · col · scaling_factor` (degree 2 in witnesses → partial length 3).
    static constexpr std::array<size_t, 21> SUBRELATION_PARTIAL_LENGTHS{ 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
                                                                         3, 3, 3, 3, 3, 3, 3, 3, 3, 3 };
    static_assert(NUM_SUBRELATIONS == SUBRELATION_PARTIAL_LENGTHS.size());
 
    // skip after lagrange_first row
    template <typename AllEntities> inline static bool skip(const AllEntities& in)
    {
        return in.lagrange_first.is_zero();
    }
 
    template <typename ContainerOverSubrelations, typename AllEntities, typename Parameters>
    static void accumulate(ContainerOverSubrelations& accumulator,
                           const AllEntities& in,
                           const Parameters& /* unused */,
                           const FF& scaling_factor);
};
 
template <typename FF> using ECCVMShiftableInitRelation = Relation<ECCVMShiftableInitRelationImpl<FF>>;
 
} // namespace bb