chainable.hpp

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#ifndef __STAN__AGRAD__REV__CHAINABLE_HPP__
#define __STAN__AGRAD__REV__CHAINABLE_HPP__

#include <vector>
#include <stan/agrad/rev/var_stack.hpp>

namespace stan {
  namespace agrad {

    class chainable {

    public:

      chainable() { }

      ~chainable() { 
        // handled automatically
      }

      virtual void chain() {
      }

      virtual void init_dependent() {
      }

      virtual void set_zero_adjoint() {
      }

      static inline void* operator new(size_t nbytes) {
        return memalloc_.alloc(nbytes);
      }
    };

    
    
    static void set_zero_all_adjoints() {
      for (size_t i = 0; i < var_stack_.size(); ++i)
        var_stack_[i]->set_zero_adjoint();
      for (size_t i = 0; i < var_nochain_stack_.size(); ++i)
        var_nochain_stack_[i]->set_zero_adjoint();
    }

    static void grad(chainable* vi) {
      std::vector<chainable*>::reverse_iterator it;

      vi->init_dependent(); 
      // propagate derivates for vars
      for (it = var_stack_.rbegin(); it < var_stack_.rend(); ++it)
        (*it)->chain();
    }

  }
}
#endif