trunc.hpp

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#ifndef STAN__AGRAD__REV__FUNCTIONS__TRUNC_HPP
#define STAN__AGRAD__REV__FUNCTIONS__TRUNC_HPP

#include <math.h>
#include <stan/agrad/rev/var.hpp>
#include <stan/agrad/rev/internal/v_vari.hpp>
#include <boost/math/special_functions/fpclassify.hpp>

namespace stan {
  namespace agrad {

    namespace {
      class trunc_vari : public op_v_vari {
      public:
        trunc_vari(vari* avi) :
          op_v_vari(::trunc(avi->val_),avi) {
        }
        void chain() {
          if (unlikely(boost::math::isnan(avi_->val_)))
            avi_->adj_ = std::numeric_limits<double>::quiet_NaN();
        }
      };
    }

    inline var trunc(const stan::agrad::var& a) {
      return var(new trunc_vari(a.vi_));
    }

  }
}
#endif