// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2023 Google Inc. All rights reserved.
// http://ceres-solver.org/
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// Author: sameeragarwal@google.com (Sameer Agarwal)

#include "ceres/detect_structure.h"

#include "Eigen/Core"
#include "ceres/block_structure.h"
#include "gtest/gtest.h"

namespace ceres {
namespace internal {

TEST(DetectStructure, EverythingStatic) {
  const int expected_row_block_size = 2;
  const int expected_e_block_size = 3;
  const int expected_f_block_size = 4;

  CompressedRowBlockStructure bs;

  bs.cols.emplace_back();
  bs.cols.back().size = 3;
  bs.cols.back().position = 0;

  bs.cols.emplace_back();
  bs.cols.back().size = 4;
  bs.cols.back().position = 3;

  bs.cols.emplace_back();
  bs.cols.back().size = 4;
  bs.cols.back().position = 7;

  {
    bs.rows.emplace_back();
    CompressedRow& row = bs.rows.back();
    row.block.size = 2;
    row.block.position = 0;
    row.cells.emplace_back(0, 0);
    row.cells.emplace_back(1, 0);
  }

  {
    bs.rows.emplace_back();
    CompressedRow& row = bs.rows.back();
    row.block.size = 2;
    row.block.position = 2;
    row.cells.emplace_back(0, 0);
    row.cells.emplace_back(2, 0);
  }

  int row_block_size = 0;
  int e_block_size = 0;
  int f_block_size = 0;
  const int num_eliminate_blocks = 1;
  DetectStructure(
      bs, num_eliminate_blocks, &row_block_size, &e_block_size, &f_block_size);

  EXPECT_EQ(row_block_size, expected_row_block_size);
  EXPECT_EQ(e_block_size, expected_e_block_size);
  EXPECT_EQ(f_block_size, expected_f_block_size);
}

TEST(DetectStructure, DynamicRow) {
  const int expected_row_block_size = Eigen::Dynamic;
  const int expected_e_block_size = 3;
  const int expected_f_block_size = 4;

  CompressedRowBlockStructure bs;

  bs.cols.emplace_back();
  bs.cols.back().size = 3;
  bs.cols.back().position = 0;

  bs.cols.emplace_back();
  bs.cols.back().size = 4;
  bs.cols.back().position = 3;

  bs.cols.emplace_back();
  bs.cols.back().size = 4;
  bs.cols.back().position = 7;

  {
    bs.rows.emplace_back();
    CompressedRow& row = bs.rows.back();
    row.block.size = 2;
    row.block.position = 0;
    row.cells.emplace_back(0, 0);
    row.cells.emplace_back(1, 0);
  }

  {
    bs.rows.emplace_back();
    CompressedRow& row = bs.rows.back();
    row.block.size = 1;
    row.block.position = 2;
    row.cells.emplace_back(0, 0);
    row.cells.emplace_back(2, 0);
  }

  int row_block_size = 0;
  int e_block_size = 0;
  int f_block_size = 0;
  const int num_eliminate_blocks = 1;
  DetectStructure(
      bs, num_eliminate_blocks, &row_block_size, &e_block_size, &f_block_size);

  EXPECT_EQ(row_block_size, expected_row_block_size);
  EXPECT_EQ(e_block_size, expected_e_block_size);
  EXPECT_EQ(f_block_size, expected_f_block_size);
}

TEST(DetectStructure, DynamicFBlockDifferentRows) {
  const int expected_row_block_size = 2;
  const int expected_e_block_size = 3;
  const int expected_f_block_size = Eigen::Dynamic;

  CompressedRowBlockStructure bs;

  bs.cols.emplace_back();
  bs.cols.back().size = 3;
  bs.cols.back().position = 0;

  bs.cols.emplace_back();
  bs.cols.back().size = 4;
  bs.cols.back().position = 3;

  bs.cols.emplace_back();
  bs.cols.back().size = 3;
  bs.cols.back().position = 7;

  {
    bs.rows.emplace_back();
    CompressedRow& row = bs.rows.back();
    row.block.size = 2;
    row.block.position = 0;
    row.cells.emplace_back(0, 0);
    row.cells.emplace_back(1, 0);
  }

  {
    bs.rows.emplace_back();
    CompressedRow& row = bs.rows.back();
    row.block.size = 2;
    row.block.position = 2;
    row.cells.emplace_back(0, 0);
    row.cells.emplace_back(2, 0);
  }

  int row_block_size = 0;
  int e_block_size = 0;
  int f_block_size = 0;
  const int num_eliminate_blocks = 1;
  DetectStructure(
      bs, num_eliminate_blocks, &row_block_size, &e_block_size, &f_block_size);

  EXPECT_EQ(row_block_size, expected_row_block_size);
  EXPECT_EQ(e_block_size, expected_e_block_size);
  EXPECT_EQ(f_block_size, expected_f_block_size);
}

TEST(DetectStructure, DynamicEBlock) {
  const int expected_row_block_size = 2;
  const int expected_e_block_size = Eigen::Dynamic;
  const int expected_f_block_size = 3;

  CompressedRowBlockStructure bs;

  bs.cols.emplace_back();
  bs.cols.back().size = 3;
  bs.cols.back().position = 0;

  bs.cols.emplace_back();
  bs.cols.back().size = 4;
  bs.cols.back().position = 3;

  bs.cols.emplace_back();
  bs.cols.back().size = 3;
  bs.cols.back().position = 7;

  {
    bs.rows.emplace_back();
    CompressedRow& row = bs.rows.back();
    row.block.size = 2;
    row.block.position = 0;
    row.cells.emplace_back(0, 0);
    row.cells.emplace_back(2, 0);
  }

  {
    bs.rows.emplace_back();
    CompressedRow& row = bs.rows.back();
    row.block.size = 2;
    row.block.position = 2;
    row.cells.emplace_back(1, 0);
    row.cells.emplace_back(2, 0);
  }

  int row_block_size = 0;
  int e_block_size = 0;
  int f_block_size = 0;
  const int num_eliminate_blocks = 2;
  DetectStructure(
      bs, num_eliminate_blocks, &row_block_size, &e_block_size, &f_block_size);

  EXPECT_EQ(row_block_size, expected_row_block_size);
  EXPECT_EQ(e_block_size, expected_e_block_size);
  EXPECT_EQ(f_block_size, expected_f_block_size);
}

TEST(DetectStructure, DynamicFBlockSameRow) {
  const int expected_row_block_size = 2;
  const int expected_e_block_size = 3;
  const int expected_f_block_size = Eigen::Dynamic;

  CompressedRowBlockStructure bs;

  bs.cols.emplace_back();
  bs.cols.back().size = 3;
  bs.cols.back().position = 0;

  bs.cols.emplace_back();
  bs.cols.back().size = 4;
  bs.cols.back().position = 3;

  bs.cols.emplace_back();
  bs.cols.back().size = 3;
  bs.cols.back().position = 7;

  {
    bs.rows.emplace_back();
    CompressedRow& row = bs.rows.back();
    row.block.size = 2;
    row.block.position = 0;
    row.cells.emplace_back(0, 0);
    row.cells.emplace_back(1, 0);
    row.cells.emplace_back(2, 0);
  }

  int row_block_size = 0;
  int e_block_size = 0;
  int f_block_size = 0;
  const int num_eliminate_blocks = 1;
  DetectStructure(
      bs, num_eliminate_blocks, &row_block_size, &e_block_size, &f_block_size);

  EXPECT_EQ(row_block_size, expected_row_block_size);
  EXPECT_EQ(e_block_size, expected_e_block_size);
  EXPECT_EQ(f_block_size, expected_f_block_size);
}

}  // namespace internal
}  // namespace ceres