datalog_dual_semiring.hpp

Go to the documentation of this file.

 
#pragma once
 
#include <cmath>
#include <type_traits>
 
namespace pulsatrix::datalog {
 
template <typename T>
struct DualNumber {
    T value;
    T grad;
 
    [[nodiscard]] bool operator==(const DualNumber& other) const {
        return std::fabs(static_cast<double>(value) - static_cast<double>(other.value)) < 1e-9 &&
               std::fabs(static_cast<double>(grad) - static_cast<double>(other.grad)) < 1e-9;
    }
    [[nodiscard]] bool operator!=(const DualNumber& other) const { return !(*this == other); }
};
 
template <typename T>
struct DualSemiring {
    static_assert(std::is_floating_point_v<T>, "DualSemiring<T> requires a floating-point T (double or float)");
 
    using Value = DualNumber<T>;
 
    [[nodiscard]] static constexpr Value zero() { return Value{static_cast<T>(0), static_cast<T>(0)}; }
    [[nodiscard]] static constexpr Value one() { return Value{static_cast<T>(1), static_cast<T>(0)}; }
    [[nodiscard]] static constexpr Value add(Value a, Value b) { return Value{a.value + b.value, a.grad + b.grad}; }
    [[nodiscard]] static constexpr Value mul(Value a, Value b) {
        return Value{a.value * b.value, a.grad * b.value + a.value * b.grad};
    }
};
 
}  // namespace pulsatrix::datalog