// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2022 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.
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//   this list of conditions and the following disclaimer in the documentation
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//
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#include <algorithm>

#include "benchmark/benchmark.h"
#include "ceres/eigen_vector_ops.h"
#include "ceres/parallel_for.h"

namespace ceres::internal {

const int kVectorSize = 64 * 1024 * 1024 / sizeof(double);

static void SetZero(benchmark::State& state) {
  Vector x = Vector::Random(kVectorSize);
  for (auto _ : state) {
    x.setZero();
  }
  CHECK_EQ(x.squaredNorm(), 0.);
}
BENCHMARK(SetZero);

static void SetZeroParallel(benchmark::State& state) {
  const int num_threads = state.range(0);
  ContextImpl context;
  context.EnsureMinimumThreads(num_threads);

  Vector x = Vector::Random(kVectorSize);
  for (auto _ : state) {
    ParallelSetZero(&context, num_threads, x);
  }
  CHECK_EQ(x.squaredNorm(), 0.);
}
BENCHMARK(SetZeroParallel)->Arg(1)->Arg(2)->Arg(4)->Arg(8)->Arg(16);

static void Negate(benchmark::State& state) {
  Vector x = Vector::Random(kVectorSize).normalized();
  const Vector x_init = x;

  for (auto _ : state) {
    x = -x;
  }
  CHECK((x - x_init).squaredNorm() == 0. || (x + x_init).squaredNorm() == 0);
}
BENCHMARK(Negate);

static void NegateParallel(benchmark::State& state) {
  const int num_threads = state.range(0);
  ContextImpl context;
  context.EnsureMinimumThreads(num_threads);

  Vector x = Vector::Random(kVectorSize).normalized();
  const Vector x_init = x;

  for (auto _ : state) {
    ParallelAssign(&context, num_threads, x, -x);
  }
  CHECK((x - x_init).squaredNorm() == 0. || (x + x_init).squaredNorm() == 0);
}
BENCHMARK(NegateParallel)->Arg(1)->Arg(2)->Arg(4)->Arg(8)->Arg(16);

static void Assign(benchmark::State& state) {
  Vector x = Vector::Random(kVectorSize);
  Vector y = Vector(kVectorSize);
  for (auto _ : state) {
    y.block(0, 0, kVectorSize, 1) = x.block(0, 0, kVectorSize, 1);
  }
  CHECK_EQ((y - x).squaredNorm(), 0.);
}
BENCHMARK(Assign);

static void AssignParallel(benchmark::State& state) {
  const int num_threads = state.range(0);
  ContextImpl context;
  context.EnsureMinimumThreads(num_threads);

  Vector x = Vector::Random(kVectorSize);
  Vector y = Vector(kVectorSize);

  for (auto _ : state) {
    ParallelAssign(&context, num_threads, y, x);
  }
  CHECK_EQ((y - x).squaredNorm(), 0.);
}
BENCHMARK(AssignParallel)->Arg(1)->Arg(2)->Arg(4)->Arg(8)->Arg(16);

static void D2X(benchmark::State& state) {
  const Vector x = Vector::Random(kVectorSize);
  const Vector D = Vector::Random(kVectorSize);
  Vector y = Vector::Zero(kVectorSize);
  for (auto _ : state) {
    y = D.array().square() * x.array();
  }
  CHECK_GT(y.squaredNorm(), 0.);
}
BENCHMARK(D2X);

static void D2XParallel(benchmark::State& state) {
  const int num_threads = state.range(0);
  ContextImpl context;
  context.EnsureMinimumThreads(num_threads);

  const Vector x = Vector::Random(kVectorSize);
  const Vector D = Vector::Random(kVectorSize);
  Vector y = Vector(kVectorSize);

  for (auto _ : state) {
    ParallelAssign(&context, num_threads, y, D.array().square() * x.array());
  }
  CHECK_GT(y.squaredNorm(), 0.);
}
BENCHMARK(D2XParallel)->Arg(1)->Arg(2)->Arg(4)->Arg(8)->Arg(16);

static void DivideSqrt(benchmark::State& state) {
  Vector diagonal = Vector::Random(kVectorSize).array().abs();
  const double radius = 0.5;
  for (auto _ : state) {
    diagonal = (diagonal / radius).array().sqrt();
  }
  CHECK_GT(diagonal.squaredNorm(), 0.);
}
BENCHMARK(DivideSqrt);

static void DivideSqrtParallel(benchmark::State& state) {
  const int num_threads = state.range(0);
  ContextImpl context;
  context.EnsureMinimumThreads(num_threads);

  Vector diagonal = Vector::Random(kVectorSize).array().abs();
  const double radius = 0.5;
  for (auto _ : state) {
    ParallelAssign(
        &context, num_threads, diagonal, (diagonal / radius).cwiseSqrt());
  }
  CHECK_GT(diagonal.squaredNorm(), 0.);
}
BENCHMARK(DivideSqrtParallel)->Arg(1)->Arg(2)->Arg(4)->Arg(8)->Arg(16);

static void Clamp(benchmark::State& state) {
  Vector diagonal = Vector::Random(kVectorSize);
  const double min = -0.5;
  const double max = 0.5;
  for (auto _ : state) {
    for (int i = 0; i < kVectorSize; ++i) {
      diagonal[i] = std::min(std::max(diagonal[i], min), max);
    }
  }
  CHECK_LE(diagonal.maxCoeff(), 0.5);
  CHECK_GE(diagonal.minCoeff(), -0.5);
}
BENCHMARK(Clamp);

static void ClampParallel(benchmark::State& state) {
  const int num_threads = state.range(0);
  ContextImpl context;
  context.EnsureMinimumThreads(num_threads);

  Vector diagonal = Vector::Random(kVectorSize);
  const double min = -0.5;
  const double max = 0.5;
  for (auto _ : state) {
    ParallelAssign(
        &context, num_threads, diagonal, diagonal.array().max(min).min(max));
  }
  CHECK_LE(diagonal.maxCoeff(), 0.5);
  CHECK_GE(diagonal.minCoeff(), -0.5);
}
BENCHMARK(ClampParallel)->Arg(1)->Arg(2)->Arg(4)->Arg(8)->Arg(16);

static void Norm(benchmark::State& state) {
  const Vector x = Vector::Random(kVectorSize);

  double total = 0.;
  for (auto _ : state) {
    total += x.norm();
  }
  CHECK_GT(total, 0.);
}
BENCHMARK(Norm);

static void NormParallel(benchmark::State& state) {
  const int num_threads = state.range(0);
  ContextImpl context;
  context.EnsureMinimumThreads(num_threads);

  const Vector x = Vector::Random(kVectorSize);

  double total = 0.;
  for (auto _ : state) {
    total += Norm(x, &context, num_threads);
  }
  CHECK_GT(total, 0.);
}
BENCHMARK(NormParallel)->Arg(1)->Arg(2)->Arg(4)->Arg(8)->Arg(16);

static void Dot(benchmark::State& state) {
  const Vector x = Vector::Random(kVectorSize);
  const Vector y = Vector::Random(kVectorSize);

  double total = 0.;
  for (auto _ : state) {
    total += x.dot(y);
  }
  CHECK_NE(total, 0.);
}
BENCHMARK(Dot);

static void DotParallel(benchmark::State& state) {
  const int num_threads = state.range(0);
  ContextImpl context;
  context.EnsureMinimumThreads(num_threads);

  const Vector x = Vector::Random(kVectorSize);
  const Vector y = Vector::Random(kVectorSize);

  double total = 0.;
  for (auto _ : state) {
    total += Dot(x, y, &context, num_threads);
  }
  CHECK_NE(total, 0.);
}
BENCHMARK(DotParallel)->Arg(1)->Arg(2)->Arg(4)->Arg(8)->Arg(16);

static void Axpby(benchmark::State& state) {
  const Vector x = Vector::Random(kVectorSize);
  const Vector y = Vector::Random(kVectorSize);
  Vector z = Vector::Zero(kVectorSize);
  const double a = 3.1415;
  const double b = 1.2345;

  for (auto _ : state) {
    z = a * x + b * y;
  }
  CHECK_GT(z.squaredNorm(), 0.);
}
BENCHMARK(Axpby);

static void AxpbyParallel(benchmark::State& state) {
  const int num_threads = state.range(0);
  ContextImpl context;
  context.EnsureMinimumThreads(num_threads);

  const Vector x = Vector::Random(kVectorSize);
  const Vector y = Vector::Random(kVectorSize);
  Vector z = Vector::Zero(kVectorSize);
  const double a = 3.1415;
  const double b = 1.2345;

  for (auto _ : state) {
    Axpby(a, x, b, y, z, &context, num_threads);
  }
  CHECK_GT(z.squaredNorm(), 0.);
}
BENCHMARK(AxpbyParallel)->Arg(1)->Arg(2)->Arg(4)->Arg(8)->Arg(16);

}  // namespace ceres::internal

BENCHMARK_MAIN();