Phi.hpp

Go to the documentation of this file.

#ifndef STAN_MATH_REV_FUN_PHI_HPP
#define STAN_MATH_REV_FUN_PHI_HPP
 
#include <stan/math/rev/meta.hpp>
#include <stan/math/rev/core.hpp>
#include <stan/math/prim/fun/Phi.hpp>
#include <cmath>
 
namespace stan {
namespace math {
 
inline var Phi(const var& a) {
  return make_callback_var(Phi(a.val()), [a](auto& vi) mutable {
    a.adj() += vi.adj() * INV_SQRT_TWO_PI * std::exp(-0.5 * a.val() * a.val());
  });
}
 
template <typename T, require_var_matrix_t<T>* = nullptr>
inline auto Phi(const T& a) {
  return make_callback_var(Phi(a.val()), [a](auto& vi) mutable {
    a.adj().array() += vi.adj().array() * INV_SQRT_TWO_PI
                       * (-0.5 * a.val().array().square()).exp();
  });
}
 
}  // namespace math
}  // namespace stan
#endif