var.hpp

Go to the documentation of this file.

#pragma once
 
// \brief Var type for reverse-mode automatic differentiation using Wirtinger calculus.
 
#include "async.hpp"
#include "reverse_value.hpp"
#include "scheduler.hpp"
#include <cmath>
 
namespace uni20::async
{
 
template <typename T> class Var {
  public:
    using value_type = T;
 
    Var() = default;
    Var(Var&&) = default;
    Var& operator=(Var&&) = default;
 
    Var(Var const&) = delete;
    Var& operator=(Var const&) = delete;
 
    Var(Var& other) : value(other.value) { other.grad += grad.input(); }
 
    Var(Async<T> const& other) : value(other) {}
 
    Var& operator=(Var& other)
    {
      grad = ReverseValue<T>{};
      other.grad += grad.input();
      value = other.value;
      return *this;
    }
 
    template <typename U>
      requires std::convertible_to<U, T>
    Var(U&& val) : value(std::forward<U>(val))
    {}
 
    Async<T>& backprop() & { return this->grad.backprop(); }
 
    Async<T> const& backprop() const& { return this->grad.backprop(); }
 
    Async<T> backprop() && { return std::move(this->grad).backprop(); }
 
    Async<T> value;
    ReverseValue<T> grad;
};
 
} // namespace uni20::async