fabs.hpp

Go to the documentation of this file.

#ifndef __STAN__AGRAD__REV__FABS_HPP__
#define __STAN__AGRAD__REV__FABS_HPP__

#include <stan/agrad/rev/var.hpp>
#include <stan/agrad/rev/vari.hpp>
#include <stan/agrad/rev/operator_unary_negative.hpp>

namespace stan {
  namespace agrad {
    
    inline var fabs(const var& a) {
      // cut-and-paste from abs()
      if (a.val() > 0.0)
        return a;
      if (a.val() < 0.0)
        return var(new neg_vari(a.vi_));
      // FIXME:  is this right?  breaks connection to a
      return var(new vari(0.0));
    }

  }
}
#endif