ODEStateObserver.hpp

 
 
#pragma once
 
#include "AstGlobal.h"
#include "AstUtil/TypeTraits.hpp"
 
AST_NAMESPACE_BEGIN
 
class ODEIntegrator;
 
enum EODEAction
{
    eContinue = 0,
    eStop = 1,
};
 
class AST_MATH_API ODEStateObserver
{
public:
    virtual ~ODEStateObserver() = default;
 
    virtual EODEAction onStateUpdate(double* y, double& x, ODEIntegrator* integrator) = 0;
 
};
 
 
class ODEStateObserverGenericHelper
{
public:
    // 版本1: 支持 func_(y, x, integrator)
    template<typename F>
    static A_ALWAYS_INLINE auto call_func(F& func, double* y, double& x, ODEIntegrator* integrator) 
        -> typename std::enable_if<is_callable<F, double*, double&, ODEIntegrator*>::value, decltype(std::declval<F>()(y, x, integrator))>::type
    {
        return func(y, x, integrator);
    }
    
    // 版本2: 支持 func_(y, x)
    template<typename F>
    static A_ALWAYS_INLINE auto call_func(F& func, double* y, double& x, ODEIntegrator* integrator) 
        -> typename std::enable_if<is_callable<F, double*, double&>::value, decltype(std::declval<F>()(y, x))>::type
    {
        return func(y, x);
    }
    
    // 版本3: 支持 func_(y)
    template<typename F>
    static A_ALWAYS_INLINE auto call_func(F& func, double* y, double& x, ODEIntegrator* integrator) 
        -> typename std::enable_if<is_callable<F, double*>::value, decltype(std::declval<F>()(y))>::type
    {
        return func(y);
    }
};
 
template<typename Func>
class ODEStateObserverGeneric: public ODEStateObserver
{
public:
    using Self = ODEStateObserverGeneric<Func>;
    using FuncType = Func;
    explicit ODEStateObserverGeneric(Func func) 
        : func_(std::move(func)) 
    {}
    
    EODEAction onStateUpdate(double* y, double& x, ODEIntegrator* integrator) override {
        return this->operator()(y, x, integrator);
    }
    
private:
    Func func_;
private:
    // 处理不同的返回类型
    template<typename F = FuncType>
    A_ALWAYS_INLINE
    typename std::enable_if<!std::is_void<decltype(
        ODEStateObserverGenericHelper::call_func
        (std::declval<F&>(), std::declval<double*>(), std::declval<double&>(), std::declval<ODEIntegrator*>()))>::value, EODEAction>::type
    operator()(double* y, double& x, ODEIntegrator* integrator) {
        return ODEStateObserverGenericHelper::call_func(func_, y, x, integrator);
    }
 
    template<typename F = FuncType>
    A_ALWAYS_INLINE
    typename std::enable_if<std::is_void<decltype(
        ODEStateObserverGenericHelper::call_func
        (std::declval<F&>(), std::declval<double*>(), std::declval<double&>(), std::declval<ODEIntegrator*>()))>::value, EODEAction>::type
    operator()(double* y, double& x, ODEIntegrator* integrator) {
        ODEStateObserverGenericHelper::call_func(func_, y, x, integrator);
        return EODEAction::eContinue;
    }
};
 
AST_NAMESPACE_END