// Ceres Solver - A fast non-linear least squares minimizer
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// http://ceres-solver.org/
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// Author: sameeragarwal@google.com (Sameer Agarwal)

#include "ceres/block_random_access_dense_matrix.h"

#include <utility>
#include <vector>

#include "ceres/internal/eigen.h"
#include "ceres/parallel_vector_ops.h"

namespace ceres::internal {

BlockRandomAccessDenseMatrix::BlockRandomAccessDenseMatrix(
    std::vector<Block> blocks, ContextImpl* context, int num_threads)
    : blocks_(std::move(blocks)), context_(context), num_threads_(num_threads) {
  const int num_blocks = blocks_.size();
  num_rows_ = NumScalarEntries(blocks_);
  values_ = std::make_unique<double[]>(num_rows_ * num_rows_);
  cell_infos_ = std::make_unique<CellInfo[]>(num_blocks * num_blocks);
  for (int i = 0; i < num_blocks * num_blocks; ++i) {
    cell_infos_[i].values = values_.get();
  }

  SetZero();
}

CellInfo* BlockRandomAccessDenseMatrix::GetCell(const int row_block_id,
                                                const int col_block_id,
                                                int* row,
                                                int* col,
                                                int* row_stride,
                                                int* col_stride) {
  *row = blocks_[row_block_id].position;
  *col = blocks_[col_block_id].position;
  *row_stride = num_rows_;
  *col_stride = num_rows_;
  return &cell_infos_[row_block_id * blocks_.size() + col_block_id];
}

// Assume that the user does not hold any locks on any cell blocks
// when they are calling SetZero.
void BlockRandomAccessDenseMatrix::SetZero() {
  ParallelSetZero(context_, num_threads_, values_.get(), num_rows_ * num_rows_);
}

}  // namespace ceres::internal