text: // Arguments: Doubles, Doubles, Doubles, Doubles
  #include <stan/math/prim/scal.hpp>
  
  using stan::math::var;
  using std::numeric_limits;
  using std::vector;
  
  class AgradCcdfLogExpModNormal : public AgradCcdfLogTest {
   public:
    void valid_values(vector<vector<double> >& parameters,
                      vector<double>& ccdf_log) {
      vector<double> param(4);
  
      param[0] = 0;  // y
      param[1] = 0;  // mu
      param[2] = 1;  // sigma
      param[3] = 1;  // lambda
      parameters.push_back(param);
      ccdf_log.push_back(
          std::log(1.0 - 0.2384217081348766198445));  // expected ccdf_log
  
      param[0] = 1;  // y
      param[1] = 0;  // mu
      param[2] = 1;  // sigma
      param[3] = 1;  // lambda
      parameters.push_back(param);
      ccdf_log.push_back(
          std::log(1.0 - 0.538079416212226213645));  // expected ccdf_log
    }
  
    void invalid_values(vector<size_t>& index, vector<double>& value) {
      // y
  
      // mu
      index.push_back(1U);
      value.push_back(-numeric_limits<double>::infinity());
  
      index.push_back(1U);
      value.push_back(numeric_limits<double>::infinity());
  
      // sigma
      index.push_back(2U);
      value.push_back(-numeric_limits<double>::infinity());
  
      index.push_back(2U);
      value.push_back(-1.0);
  
      index.push_back(2U);
      value.push_back(0.0);
  
      // lambda
      index.push_back(3U);
      value.push_back(-numeric_limits<double>::infinity());
  
      index.push_back(3U);
      value.push_back(-1.0);
  
      index.push_back(3U);
      value.push_back(0.0);
  
      index.push_back(3U);
      value.push_back(numeric_limits<double>::infinity());
    }
  
    bool has_lower_bound() { return false; }
  
    bool has_upper_bound() { return false; }
  
    template <typename T_y, typename T_loc, typename T_scale,
              typename T_inv_scale, typename T4, typename T5>
    typename stan::return_type<T_y, T_loc, T_scale, T_inv_scale>::type ccdf_log(
        const T_y& y, const T_loc& mu, const T_scale& sigma,
        const T_inv_scale& lambda, const T4&, const T5&) {
      return stan::math::exp_mod_normal_ccdf_log(y, mu, sigma, lambda);
    }
  
    template <typename T_y, typename T_loc, typename T_scale,
              typename T_inv_scale, typename T4, typename T5>
    typename stan::return_type<T_y, T_loc, T_scale, T_inv_scale>::type
    ccdf_log_function(const T_y& y, const T_loc& mu, const T_scale& sigma,
                      const T_inv_scale& lambda, const T4&, const T5&) {
      return log(
          1.0
          - (0.5 * (1 + erf((y - mu) / (sqrt(2.0) * sigma)))
             - exp(-lambda * (y - mu) + lambda * sigma * lambda * sigma / 2.0)
                   * 0.5
                   * (1
                      + erf(((y - mu) - sigma * lambda * sigma)
                            / (sqrt(2.0) * sigma)))));
    }
  };
  