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

// Copyright 2015 Google Inc. All rights reserved.

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

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// Author: sameeragarwal@google.com (Sameer Agarwal)

#include <algorithm>

#include <numeric>

#include "ceres/compressed_col_sparse_matrix_utils.h"

#include "ceres/internal/port.h"

#include "ceres/triplet_sparse_matrix.h"

#include "glog/logging.h"

#include "gtest/gtest.h"

#include "Eigen/SparseCore"

namespace ceres {

namespace internal {

using std::vector;

TEST(_, BlockPermutationToScalarPermutation) {

  vector<int> blocks;

  //  Block structure

  //  0  --1-  ---2---  ---3---  4

  // [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

  blocks.push_back(1);

  blocks.push_back(2);

  blocks.push_back(3);

  blocks.push_back(3);

  blocks.push_back(1);

  // Block ordering

  // [1, 0, 2, 4, 5]

  vector<int> block_ordering;

  block_ordering.push_back(1);

  block_ordering.push_back(0);

  block_ordering.push_back(2);

  block_ordering.push_back(4);

  block_ordering.push_back(3);

  // Expected ordering

  // [1, 2, 0, 3, 4, 5, 9, 6, 7, 8]

  vector<int> expected_scalar_ordering;

  expected_scalar_ordering.push_back(1);

  expected_scalar_ordering.push_back(2);

  expected_scalar_ordering.push_back(0);

  expected_scalar_ordering.push_back(3);

  expected_scalar_ordering.push_back(4);

  expected_scalar_ordering.push_back(5);

  expected_scalar_ordering.push_back(9);

  expected_scalar_ordering.push_back(6);

  expected_scalar_ordering.push_back(7);

  expected_scalar_ordering.push_back(8);

  vector<int> scalar_ordering;

  BlockOrderingToScalarOrdering(blocks,

                                block_ordering,

                                &scalar_ordering);

  EXPECT_EQ(scalar_ordering.size(), expected_scalar_ordering.size());

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

    EXPECT_EQ(scalar_ordering[i], expected_scalar_ordering[i]);

  }

}

void FillBlock(const vector<int>& row_blocks,

               const vector<int>& col_blocks,

               const int row_block_id,

               const int col_block_id,

               vector<Eigen::Triplet<double> >* triplets) {

  const int row_offset = std::accumulate(&row_blocks[0], &row_blocks[row_block_id], 0);

  const int col_offset = std::accumulate(&col_blocks[0], &col_blocks[col_block_id], 0);

  for (int r = 0; r < row_blocks[row_block_id]; ++r) {

    for (int c = 0; c < col_blocks[col_block_id]; ++c) {

      triplets->push_back(Eigen::Triplet<double>(row_offset + r, col_offset + c, 1.0));

    }

  }

}

TEST(_, ScalarMatrixToBlockMatrix) {

  // Block sparsity.

  //

  //     [1 2 3 2]

  // [1]  x   x

  // [2]    x   x

  // [2]  x x

  // num_nonzeros = 1 + 3 + 4 + 4 + 1 + 2 = 15

  vector<int> col_blocks;

  col_blocks.push_back(1);

  col_blocks.push_back(2);

  col_blocks.push_back(3);

  col_blocks.push_back(2);

  vector<int> row_blocks;

  row_blocks.push_back(1);

  row_blocks.push_back(2);

  row_blocks.push_back(2);

  const int num_rows = std::accumulate(row_blocks.begin(), row_blocks.end(), 0.0);

  const int num_cols = std::accumulate(col_blocks.begin(), col_blocks.end(), 0.0);

  vector<Eigen::Triplet<double> > triplets;

  FillBlock(row_blocks, col_blocks, 0, 0, &triplets);

  FillBlock(row_blocks, col_blocks, 2, 0, &triplets);

  FillBlock(row_blocks, col_blocks, 1, 1, &triplets);

  FillBlock(row_blocks, col_blocks, 2, 1, &triplets);

  FillBlock(row_blocks, col_blocks, 0, 2, &triplets);

  FillBlock(row_blocks, col_blocks, 1, 3, &triplets);

  Eigen::SparseMatrix<double> sparse_matrix(num_rows, num_cols);

  sparse_matrix.setFromTriplets(triplets.begin(), triplets.end());

  vector<int> expected_compressed_block_rows;

  expected_compressed_block_rows.push_back(0);

  expected_compressed_block_rows.push_back(2);

  expected_compressed_block_rows.push_back(1);

  expected_compressed_block_rows.push_back(2);

  expected_compressed_block_rows.push_back(0);

  expected_compressed_block_rows.push_back(1);

  vector<int> expected_compressed_block_cols;

  expected_compressed_block_cols.push_back(0);

  expected_compressed_block_cols.push_back(2);

  expected_compressed_block_cols.push_back(4);

  expected_compressed_block_cols.push_back(5);

  expected_compressed_block_cols.push_back(6);

  vector<int> compressed_block_rows;

  vector<int> compressed_block_cols;

  CompressedColumnScalarMatrixToBlockMatrix(

      sparse_matrix.innerIndexPtr(),

      sparse_matrix.outerIndexPtr(),

      row_blocks,

      col_blocks,

      &compressed_block_rows,

      &compressed_block_cols);

  EXPECT_EQ(compressed_block_rows, expected_compressed_block_rows);

  EXPECT_EQ(compressed_block_cols, expected_compressed_block_cols);

}

class SolveUpperTriangularTest : public ::testing::Test {

 protected:

  void SetUp() {

    cols.resize(5);

    rows.resize(7);

    values.resize(7);

    cols[0] = 0;

    rows[0] = 0;

    values[0] = 0.50754;

    cols[1] = 1;

    rows[1] = 1;

    values[1] = 0.80483;

    cols[2] = 2;

    rows[2] = 1;

    values[2] = 0.14120;

    rows[3] = 2;

    values[3] = 0.3;

    cols[3] = 4;

    rows[4] = 0;

    values[4] = 0.77696;

    rows[5] = 1;

    values[5] = 0.41860;

    rows[6] = 3;

    values[6] = 0.88979;

    cols[4] = 7;

  }

  vector<int> cols;

  vector<int> rows;

  vector<double> values;

};

TEST_F(SolveUpperTriangularTest, SolveInPlace) {

  double rhs_and_solution[] = {1.0, 1.0, 2.0, 2.0};

  const double expected[] = { -1.4706, -1.0962, 6.6667, 2.2477};

  SolveUpperTriangularInPlace<int>(cols.size() - 1,

                                   &rows[0],

                                   &cols[0],

                                   &values[0],

                                   rhs_and_solution);

  for (int i = 0; i < 4; ++i) {

    EXPECT_NEAR(rhs_and_solution[i], expected[i], 1e-4) << i;

  }

}

TEST_F(SolveUpperTriangularTest, TransposeSolveInPlace) {

  double rhs_and_solution[] = {1.0, 1.0, 2.0, 2.0};

  double expected[] = {1.970288,  1.242498,  6.081864, -0.057255};

  SolveUpperTriangularTransposeInPlace<int>(cols.size() - 1,

                                            &rows[0],

                                            &cols[0],

                                            &values[0],

                                            rhs_and_solution);

  for (int i = 0; i < 4; ++i) {

    EXPECT_NEAR(rhs_and_solution[i], expected[i], 1e-4) << i;

  }

}

TEST_F(SolveUpperTriangularTest, RTRSolveWithSparseRHS) {

  double solution[4];

  double expected[] = { 6.8420e+00,   1.0057e+00,  -1.4907e-16,  -1.9335e+00,

                        1.0057e+00,   2.2275e+00,  -1.9493e+00,  -6.5693e-01,

                        -1.4907e-16,  -1.9493e+00,   1.1111e+01,   9.7381e-17,

                        -1.9335e+00,  -6.5693e-01,   9.7381e-17,   1.2631e+00 };

  for (int i = 0; i < 4; ++i) {

    SolveRTRWithSparseRHS<int>(cols.size() - 1,

                               &rows[0],

                               &cols[0],

                               &values[0],

                               i,

                               solution);

    for (int j = 0; j < 4; ++j) {

      EXPECT_NEAR(solution[j], expected[4 * i + j], 1e-3) << i;

    }

  }

}

}  // namespace internal

}  // namespace ceres