tanh.hpp

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#ifndef STAN__AGRAD__REV__FUNCTIONS__TANH_HPP
#define STAN__AGRAD__REV__FUNCTIONS__TANH_HPP

#include <cmath>
#include <stan/agrad/rev/var.hpp>
#include <stan/agrad/rev/internal/v_vari.hpp>

namespace stan {
  namespace agrad {

    namespace {
      class tanh_vari : public op_v_vari {
      public:
        tanh_vari(vari* avi) :
          op_v_vari(std::tanh(avi->val_),avi) {
        }
        void chain() {
          double cosh = std::cosh(avi_->val_);
          avi_->adj_ += adj_ / (cosh * cosh);
        }
      };
    }

    inline var tanh(const var& a) {
      return var(new tanh_vari(a.vi_));
    }

  }
}
#endif