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

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

#include <limits>

#include <vector>

#include "ceres/block_random_access_sparse_matrix.h"

#include "ceres/internal/eigen.h"

#include "glog/logging.h"

#include "gtest/gtest.h"

namespace ceres {

namespace internal {

using std::make_pair;

using std::pair;

using std::set;

using std::vector;

TEST(BlockRandomAccessSparseMatrix, GetCell) {

  vector<int> blocks;

  blocks.push_back(3);

  blocks.push_back(4);

  blocks.push_back(5);

  const int num_rows = 3 + 4 + 5;

  set< pair<int, int> > block_pairs;

  int num_nonzeros = 0;

  block_pairs.insert(make_pair(0, 0));

  num_nonzeros += blocks[0] * blocks[0];

  block_pairs.insert(make_pair(1, 1));

  num_nonzeros += blocks[1] * blocks[1];

  block_pairs.insert(make_pair(1, 2));

  num_nonzeros += blocks[1] * blocks[2];

  block_pairs.insert(make_pair(0, 2));

  num_nonzeros += blocks[2] * blocks[0];

  BlockRandomAccessSparseMatrix m(blocks, block_pairs);

  EXPECT_EQ(m.num_rows(), num_rows);

  EXPECT_EQ(m.num_cols(), num_rows);

  for (set<pair<int, int> >::const_iterator it = block_pairs.begin();

       it != block_pairs.end();

       ++it) {

    const int row_block_id = it->first;

    const int col_block_id = it->second;

    int row;

    int col;

    int row_stride;

    int col_stride;

    CellInfo* cell =  m.GetCell(row_block_id, col_block_id,

                                &row, &col,

                                &row_stride, &col_stride);

    EXPECT_TRUE(cell != NULL);

    EXPECT_EQ(row, 0);

    EXPECT_EQ(col, 0);

    EXPECT_EQ(row_stride, blocks[row_block_id]);

    EXPECT_EQ(col_stride, blocks[col_block_id]);

    // Write into the block

    MatrixRef(cell->values, row_stride, col_stride).block(

        row, col, blocks[row_block_id], blocks[col_block_id]) =

        (row_block_id + 1) * (col_block_id +1) *

        Matrix::Ones(blocks[row_block_id], blocks[col_block_id]);

  }

  const TripletSparseMatrix* tsm = m.matrix();

  EXPECT_EQ(tsm->num_nonzeros(), num_nonzeros);

  EXPECT_EQ(tsm->max_num_nonzeros(), num_nonzeros);

  Matrix dense;

  tsm->ToDenseMatrix(&dense);

  double kTolerance = 1e-14;

  // (0, 0)

  EXPECT_NEAR((dense.block(0, 0, 3, 3) - Matrix::Ones(3, 3)).norm(),

              0.0,

              kTolerance);

  // (1, 1)

  EXPECT_NEAR((dense.block(3, 3, 4, 4) - 2 * 2 * Matrix::Ones(4, 4)).norm(),

              0.0,

              kTolerance);

  // (1, 2)

  EXPECT_NEAR((dense.block(3, 3 + 4, 4, 5) - 2 * 3 * Matrix::Ones(4, 5)).norm(),

              0.0,

              kTolerance);

  // (0, 2)

  EXPECT_NEAR((dense.block(0, 3 + 4, 3, 5) - 3 * 1 * Matrix::Ones(3, 5)).norm(),

              0.0,

              kTolerance);

  // There is nothing else in the matrix besides these four blocks.

  EXPECT_NEAR(dense.norm(), sqrt(9. + 16. * 16. + 36. * 20. + 9. * 15.),

              kTolerance);

  Vector x = Vector::Ones(dense.rows());

  Vector actual_y = Vector::Zero(dense.rows());

  Vector expected_y = Vector::Zero(dense.rows());

  expected_y += dense.selfadjointView<Eigen::Upper>() * x;

  m.SymmetricRightMultiply(x.data(), actual_y.data());

  EXPECT_NEAR((expected_y - actual_y).norm(), 0.0, kTolerance)

      << "actual: " << actual_y.transpose() << "\n"

      << "expected: " << expected_y.transpose()

      << "matrix: \n " << dense;

}

// IntPairToLong is private, thus this fixture is needed to access and

// test it.

class BlockRandomAccessSparseMatrixTest : public ::testing::Test {

 public:

  virtual void SetUp() {

    vector<int> blocks;

    blocks.push_back(1);

    set< pair<int, int> > block_pairs;

    block_pairs.insert(make_pair(0, 0));

    m_.reset(new BlockRandomAccessSparseMatrix(blocks, block_pairs));

  }

  void CheckIntPairToLong(int a, int b) {

    int64 value = m_->IntPairToLong(a, b);

    EXPECT_GT(value, 0) << "Overflow a = " << a << " b = " << b;

    EXPECT_GT(value, a) << "Overflow a = " << a << " b = " << b;

    EXPECT_GT(value, b) << "Overflow a = " << a << " b = " << b;

  }

  void CheckLongToIntPair() {

    uint64 max_rows =  m_->kMaxRowBlocks;

    for (int row = max_rows - 10; row < max_rows; ++row) {

      for (int col = 0; col < 10; ++col) {

        int row_computed;

        int col_computed;

        m_->LongToIntPair(m_->IntPairToLong(row, col),

                          &row_computed,

                          &col_computed);

        EXPECT_EQ(row, row_computed);

        EXPECT_EQ(col, col_computed);

      }

    }

  }

 private:

  scoped_ptr<BlockRandomAccessSparseMatrix> m_;

};

TEST_F(BlockRandomAccessSparseMatrixTest, IntPairToLongOverflow) {

  CheckIntPairToLong(std::numeric_limits<int>::max(),

                     std::numeric_limits<int>::max());

}

TEST_F(BlockRandomAccessSparseMatrixTest, LongToIntPair) {

  CheckLongToIntPair();

}

}  // namespace internal

}  // namespace ceres