// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2023 Google Inc. All rights reserved.
// http://ceres-solver.org/
//
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//
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// Author: keir@google.com (Keir Mierle)
//
// Utility functions useful for testing.

#include "ceres/test_util.h"

#include <algorithm>
#include <cmath>

#include "absl/log/check.h"
#include "absl/log/log.h"
#include "ceres/file.h"
#include "ceres/internal/port.h"
#include "ceres/stringprintf.h"
#include "ceres/types.h"
#include "gtest/gtest.h"

// This macro is used to inject additional path information specific
// to the build system.

#ifndef CERES_TEST_SRCDIR_SUFFIX
#define CERES_TEST_SRCDIR_SUFFIX ""
#endif

namespace ceres {
namespace internal {

bool ExpectClose(double x, double y, double max_abs_relative_difference) {
  if (std::isinf(x) && std::isinf(y)) {
    EXPECT_EQ(std::signbit(x), std::signbit(y));
    return true;
  }

  if (std::isnan(x) && std::isnan(y)) {
    return true;
  }

  double absolute_difference = fabs(x - y);
  double relative_difference = absolute_difference / std::max(fabs(x), fabs(y));
  if (x == 0 || y == 0) {
    // If x or y is exactly zero, then relative difference doesn't have any
    // meaning. Take the absolute difference instead.
    relative_difference = absolute_difference;
  }
  if (relative_difference > max_abs_relative_difference) {
    VLOG(1) << StringPrintf("x=%17g y=%17g abs=%17g rel=%17g",
                            x,
                            y,
                            absolute_difference,
                            relative_difference);
  }

  EXPECT_NEAR(relative_difference, 0.0, max_abs_relative_difference);
  return relative_difference <= max_abs_relative_difference;
}

void ExpectArraysCloseUptoScale(int n,
                                const double* p,
                                const double* q,
                                double tol) {
  CHECK_GT(n, 0);
  CHECK(p);
  CHECK(q);

  double p_max = 0;
  double q_max = 0;
  int p_i = 0;
  int q_i = 0;

  for (int i = 0; i < n; ++i) {
    if (std::abs(p[i]) > p_max) {
      p_max = std::abs(p[i]);
      p_i = i;
    }
    if (std::abs(q[i]) > q_max) {
      q_max = std::abs(q[i]);
      q_i = i;
    }
  }

  // If both arrays are all zeros, they are equal up to scale, but
  // for testing purposes, that's more likely to be an error than
  // a desired result.
  CHECK_NE(p_max, 0.0);
  CHECK_NE(q_max, 0.0);

  for (int i = 0; i < n; ++i) {
    double p_norm = p[i] / p[p_i];
    double q_norm = q[i] / q[q_i];

    EXPECT_NEAR(p_norm, q_norm, tol) << "i=" << i;
  }
}

void ExpectArraysClose(int n, const double* p, const double* q, double tol) {
  CHECK_GT(n, 0);
  CHECK(p);
  CHECK(q);

  for (int i = 0; i < n; ++i) {
    EXPECT_TRUE(ExpectClose(p[i], q[i], tol)) << "p[" << i << "]" << p[i] << " "
                                              << "q[" << i << "]" << q[i] << " "
                                              << "tol: " << tol;
  }
}

std::string TestFileAbsolutePath(const std::string& filename) {
  return JoinPath(::testing::SrcDir() + CERES_TEST_SRCDIR_SUFFIX, filename);
}

std::string ToString(const Solver::Options& options) {
  return StringPrintf("(%s, %s, %s, %s, %d)",
                      LinearSolverTypeToString(options.linear_solver_type),
                      SparseLinearAlgebraLibraryTypeToString(
                          options.sparse_linear_algebra_library_type),
                      options.linear_solver_ordering ? "USER" : "AUTOMATIC",
                      PreconditionerTypeToString(options.preconditioner_type),
                      options.num_threads);
}

}  // namespace internal
}  // namespace ceres