log_inv_logit_diff.hpp

Go to the documentation of this file.

#ifndef STAN_MATH_PRIM_FUN_LOG_INV_LOGIT_DIFF_HPP
#define STAN_MATH_PRIM_FUN_LOG_INV_LOGIT_DIFF_HPP
 
#include <stan/math/prim/meta.hpp>
#include <stan/math/prim/fun/is_inf.hpp>
#include <stan/math/prim/fun/log1m_exp.hpp>
#include <stan/math/prim/fun/log1p_exp.hpp>
#include <stan/math/prim/functor/apply_scalar_binary.hpp>
 
namespace stan {
namespace math {
 
template <typename T1, typename T2, require_all_arithmetic_t<T1, T2>* = nullptr>
inline return_type_t<T1, T2> log_inv_logit_diff(const T1& x, const T2& y) {
  if (is_inf(x) && x >= 0) {
    return -log1p_exp(y);
  }
  return x - log1p_exp(x) + log1m_exp(y - x) - log1p_exp(y);
}
 
template <typename T1, typename T2, require_any_container_t<T1, T2>* = nullptr>
inline auto log_inv_logit_diff(const T1& a, const T2& b) {
  return apply_scalar_binary(a, b, [&](const auto& c, const auto& d) {
    return log_inv_logit_diff(c, d);
  });
}
 
}  // namespace math
}  // namespace stan
 
#endif