// Ceres Solver - A fast non-linear least squares minimizer

// Copyright 2015 Google Inc. All rights reserved.

// http://ceres-solver.org/

//

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// modification, are permitted provided that the following conditions are met:

//

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//   this list of conditions and the following disclaimer.

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// Author: richie.stebbing@gmail.com (Richard Stebbing)

#include <cstring>

#include "ceres/dynamic_compressed_row_sparse_matrix.h"

namespace ceres {

namespace internal {

DynamicCompressedRowSparseMatrix::DynamicCompressedRowSparseMatrix(

  int num_rows,

  int num_cols,

  int initial_max_num_nonzeros)

    : CompressedRowSparseMatrix(num_rows,

                                num_cols,

                                initial_max_num_nonzeros) {

    dynamic_cols_.resize(num_rows);

    dynamic_values_.resize(num_rows);

  }

void DynamicCompressedRowSparseMatrix::InsertEntry(int row,

                                                   int col,

                                                   const double& value) {

  CHECK_GE(row, 0);

  CHECK_LT(row, num_rows());

  CHECK_GE(col, 0);

  CHECK_LT(col, num_cols());

  dynamic_cols_[row].push_back(col);

  dynamic_values_[row].push_back(value);

}

void DynamicCompressedRowSparseMatrix::ClearRows(int row_start,

                                                 int num_rows) {

  for (int r = 0; r < num_rows; ++r) {

    const int i = row_start + r;

    CHECK_GE(i, 0);

    CHECK_LT(i, this->num_rows());

    dynamic_cols_[i].resize(0);

    dynamic_values_[i].resize(0);

  }

}

void DynamicCompressedRowSparseMatrix::Finalize(int num_additional_elements) {

  // `num_additional_elements` is provided as an argument so that additional

  // storage can be reserved when it is known by the finalizer.

  CHECK_GE(num_additional_elements, 0);

  // Count the number of non-zeros and resize `cols_` and `values_`.

  int num_jacobian_nonzeros = 0;

  for (int i = 0; i < dynamic_cols_.size(); ++i) {

    num_jacobian_nonzeros += dynamic_cols_[i].size();

  }

  SetMaxNumNonZeros(num_jacobian_nonzeros + num_additional_elements);

  // Flatten `dynamic_cols_` into `cols_` and `dynamic_values_`

  // into `values_`.

  int index_into_values_and_cols = 0;

  for (int i = 0; i < num_rows(); ++i) {

    mutable_rows()[i] = index_into_values_and_cols;

    const int num_nonzero_columns = dynamic_cols_[i].size();

    if (num_nonzero_columns > 0) {

      memcpy(mutable_cols() + index_into_values_and_cols,

             &dynamic_cols_[i][0],

             dynamic_cols_[i].size() * sizeof(dynamic_cols_[0][0]));

      memcpy(mutable_values() + index_into_values_and_cols,

             &dynamic_values_[i][0],

             dynamic_values_[i].size() * sizeof(dynamic_values_[0][0]));

      index_into_values_and_cols += dynamic_cols_[i].size();

    }

  }

  mutable_rows()[num_rows()] = index_into_values_and_cols;

  CHECK_EQ(index_into_values_and_cols, num_jacobian_nonzeros)

    << "Ceres bug: final index into values_ and cols_ should be equal to "

    << "the number of jacobian nonzeros. Please contact the developers!";

}

}  // namespace internal

}  // namespace ceres