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

// Copyright 2015 Google Inc. All rights reserved.

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

//

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are met:

//

// * Redistributions of source code must retain the above copyright notice,

//   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.

// * Neither the name of Google Inc. nor the names of its contributors may be

//   used to endorse or promote products derived from this software without

//   specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

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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 "ceres/file.h"

#include "ceres/stringprintf.h"

#include "ceres/types.h"

#include "gflags/gflags.h"

#include "glog/logging.h"

#include "gtest/gtest.h"

DECLARE_string(test_srcdir);

// 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) {

  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(FLAGS_test_srcdir + CERES_TEST_SRCDIR_SUFFIX,

                  filename);

}

SolverConfig ThreadedSolverConfig(

    LinearSolverType linear_solver_type,

    SparseLinearAlgebraLibraryType sparse_linear_algebra_library_type,

    bool use_automatic_ordering,

    PreconditionerType preconditioner_type) {

  const int kNumThreads = 4;

  return SolverConfig(linear_solver_type,

                      sparse_linear_algebra_library_type,

                      use_automatic_ordering,

                      preconditioner_type,

                      kNumThreads);

}

}  // namespace internal

}  // namespace ceres