lambert_w.hpp

#ifndef STAN_MATH_REV_FUN_LAMBERT_W_HPP
#define STAN_MATH_REV_FUN_LAMBERT_W_HPP

#include <stan/math/rev/core.hpp>
#include <stan/math/rev/meta.hpp>
#include <stan/math/prim/meta.hpp>
#include <stan/math/prim/fun/lambert_w.hpp>

namespace stan {
namespace math {

namespace internal {
  class lambertw0_vari : public op_v_vari {
   public:
    explicit lambertw0_vari(vari* avi) : op_v_vari(lambert_w0(avi->val_), avi) {}
    void chain() {
      avi_->adj_ += adj_  + boost::math::lambert_w0_prime(avi_->val_) ;
    }
  };
}  // namespace internal


inline var lambert_w0(const var& a) { return var(new internal::lambertw0_vari(a.vi_)); }


}  // namespace math
}  // namespace stan

#endif