// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2023 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.
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution.
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//   used to endorse or promote products derived from this software without
//   specific prior written permission.
//
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// Author: keir@google.com (Keir Mierle)

#ifndef CERES_INTERNAL_TEST_UTIL_H_
#define CERES_INTERNAL_TEST_UTIL_H_

#include <string>

#include "absl/log/check.h"
#include "ceres/internal/disable_warnings.h"
#include "ceres/internal/export.h"
#include "ceres/problem.h"
#include "ceres/solver.h"
#include "ceres/stringprintf.h"
#include "gtest/gtest.h"

namespace ceres {
namespace internal {

// Expects that x and y have a relative difference of no more than
// max_abs_relative_difference. If either x or y is zero, then the relative
// difference is interpreted as an absolute difference.
// If x and y have the same non-finite value (inf or nan) we treat them as being
// close. In such a case no error is thrown and true is returned.
CERES_NO_EXPORT bool ExpectClose(double x,
                                 double y,
                                 double max_abs_relative_difference);

// Expects that for all i = 1,.., n - 1
//
//   |p[i] - q[i]| / max(|p[i]|, |q[i]|) < tolerance
CERES_NO_EXPORT void ExpectArraysClose(int n,
                                       const double* p,
                                       const double* q,
                                       double tolerance);

// Expects that for all i = 1,.., n - 1
//
//   |p[i] / max_norm_p - q[i] / max_norm_q| < tolerance
//
// where max_norm_p and max_norm_q are the max norms of the arrays p
// and q respectively.
CERES_NO_EXPORT void ExpectArraysCloseUptoScale(int n,
                                                const double* p,
                                                const double* q,
                                                double tolerance);

// Construct a fully qualified path for the test file depending on the
// local build/testing environment.
CERES_NO_EXPORT std::string TestFileAbsolutePath(const std::string& filename);

CERES_NO_EXPORT std::string ToString(const Solver::Options& options);

// A templated test fixture, that is used for testing Ceres end to end
// by computing a solution to the problem for a given solver
// configuration and comparing it to a reference solver configuration.
//
// It is assumed that the SystemTestProblem has an Solver::Options
// struct that contains the reference Solver configuration.
template <typename SystemTestProblem>
class CERES_NO_EXPORT SystemTest : public ::testing::Test {
 protected:
  void SetUp() final {
    SystemTestProblem system_test_problem;
    SolveAndEvaluateFinalResiduals(
        *system_test_problem.mutable_solver_options(),
        system_test_problem.mutable_problem(),
        &expected_final_residuals_);
  }

  void RunSolverForConfigAndExpectResidualsMatch(const Solver::Options& options,
                                                 Problem* problem) {
    std::vector<double> final_residuals;
    SolveAndEvaluateFinalResiduals(options, problem, &final_residuals);

    // We compare solutions by comparing their residual vectors. We do
    // not compare parameter vectors because it is much more brittle
    // and error prone to do so, since the same problem can have
    // nearly the same residuals at two completely different positions
    // in parameter space.
    CHECK_EQ(expected_final_residuals_.size(), final_residuals.size());
    for (int i = 0; i < final_residuals.size(); ++i) {
      EXPECT_NEAR(final_residuals[i],
                  expected_final_residuals_[i],
                  SystemTestProblem::kResidualTolerance)
          << "Not close enough residual:" << i;
    }
  }

  void SolveAndEvaluateFinalResiduals(const Solver::Options& options,
                                      Problem* problem,
                                      std::vector<double>* final_residuals) {
    Solver::Summary summary;
    Solve(options, problem, &summary);
    CHECK_NE(summary.termination_type, ceres::FAILURE);
    problem->Evaluate(
        Problem::EvaluateOptions(), nullptr, final_residuals, nullptr, nullptr);
  }

  std::vector<double> expected_final_residuals_;
};

}  // namespace internal
}  // namespace ceres

#include "ceres/internal/reenable_warnings.h"

#endif  // CERES_INTERNAL_TEST_UTIL_H_