#ifndef STAN_MATH_PRIM_MAT_FUN_MAX_HPP
#define STAN_MATH_PRIM_MAT_FUN_MAX_HPP

#include <stan/math/prim/arr/err/check_nonzero_size.hpp>
#include <stan/math/prim/mat/fun/Eigen.hpp>
#include <algorithm>
#include <limits>
#include <stdexcept>
#include <vector>

namespace stan {
namespace math {

/**
 * Returns the maximum coefficient in the specified
 * column vector.
 * @param x Specified vector.
 * @return Maximum coefficient value in the vector.
 * @tparam Type of values being compared and returned
 * @throw std::domain_error If the size of the vector is zero.
 */
inline int max(const std::vector<int>& x) {
  check_nonzero_size("max", "int vector", x);
  int max = x[0];
  for (size_t i = 1; i < x.size(); ++i)
    if (x[i] > max)
      max = x[i];
  return max;
}

/**
 * Returns the maximum coefficient in the specified
 * column vector.
 * @param x Specified vector.
 * @return Maximum coefficient value in the vector.
 * @tparam T Type of values being compared and returned
 */
template <typename T>
inline T max(const std::vector<T>& x) {
  if (x.size() == 0)
    return -std::numeric_limits<T>::infinity();
  T max = x[0];
  for (size_t i = 1; i < x.size(); ++i)
    if (x[i] > max)
      max = x[i];
  return max;
}

/**
 * Returns the maximum coefficient in the specified
 * vector, row vector, or matrix.
 * @param m Specified vector, row vector, or matrix.
 * @return Maximum coefficient value in the vector.
 */
template <typename T, int R, int C>
inline T max(const Eigen::Matrix<T, R, C>& m) {
  if (m.size() == 0)
    return -std::numeric_limits<double>::infinity();
  return m.maxCoeff();
}

}  // namespace math
}  // namespace stan
#endif
