partially_evaluated_multivariates.hpp

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// === AUDIT STATUS ===
// internal:    { status: Complete, auditors: [Sergei], commit: }
// external_1:  { status: not started, auditors: [], commit: }
// external_2:  { status: not started, auditors: [], commit: }
// =====================
#pragma once
 
#include "barretenberg/common/zip_view.hpp"
#include "barretenberg/polynomials/polynomial.hpp"
 
namespace bb {
 
template <typename AllEntitiesBase, typename ProverPolynomialsType, typename Polynomial>
class PartiallyEvaluatedMultivariatesBase : public AllEntitiesBase {
  public:
    // One-past the last relation-active row at this round; the sumcheck prover skips rows beyond it. Halved each round
    // to track the trace folding (here and in SumcheckProver::partially_evaluate). Populated only by flavors with a
    // static row-skip manifest; 0 means scan every row.
    size_t row_skip_active_prefix_end = 0;
 
    PartiallyEvaluatedMultivariatesBase(const ProverPolynomialsType& full_polynomials, size_t circuit_size)
    {
        for (auto [poly, full_poly] : zip_view(this->get_all(), full_polynomials.get_all())) {
            // After the initial sumcheck round, the new size is CEIL(size/2).
            size_t desired_size = (full_poly.end_index() / 2) + (full_poly.end_index() % 2);
            // partially_evaluate writes to [0, desired_size) before any read; backing memory can be left uninitialized.
            poly = Polynomial(desired_size, circuit_size / 2, 0, Polynomial::DontZeroMemory::FLAG);
        }
        if constexpr (requires { full_polynomials.row_skip_active_prefix_end; }) {
            row_skip_active_prefix_end =
                (full_polynomials.row_skip_active_prefix_end / 2) + (full_polynomials.row_skip_active_prefix_end % 2);
        }
    }
};
 
} // namespace bb