停止整合僵硬颂歌odeint [英] Stop integration in odeint with stiff ode

问题描述

我要解决一个僵硬颂歌与odeint。我在下面的<一个href=\"http://www.boost.org/doc/libs/1_57_0/libs/numeric/odeint/doc/html/boost_numeric_odeint/tutorial/stiff_systems.html\"相对=nofollow>这个（rosenbrock4_dense_output步进），但是，我的功能，可以迅速成长pretty所以我想停止整合如果x（t）的> XMAX。

I want to solve a stiff ode with odeint. I was following this (rosenbrock4_dense_output stepper) but, my function can grow pretty quickly so I want to stop the integration if x(t)>xMAX.

在此<一个href=\"http://stackoverflow.com/questions/14586059/bound-an-odeint-variable/14588283#14588283\">question,他们有一个解决方案，但因为我是新的C + +我不知道如何使用rosenbrock4_dense_output步进何时实现这一点。

In this question, they have a solution for it but since I'm new with c++ I don't know how to implement this when using a rosenbrock4_dense_output stepper.

我想看看如何具体写了rosenbrock4_dense_output步进。

I would like to see how to write this specifically for rosenbrock4_dense_output stepper.

推荐答案

目前，这是不容易可能的odeint。如果你可以在这里使用范围图书馆 你可以结合的for_each 和 find_if 算法

Currently, this is not easily possible with odeint. If you can use the range library here you can combine a for_each and a find_if algorithm.

否则，你需要编写自己的循环，这也并不难，应该与此类似：

Otherwise you need to write the loop yourself, which is also not that difficult and should be similar to this:

auto stepper = make_dense_output< rosenbrock4< double > >( 1.0e-12 , 1.0e-12 );
auto ode = make_pair( stiff_system() , stiff_system_jacobi() );

double t = 0.0;
double const end_time = 50.0;
double const dt = 0.01;
vector_type x( 2 , 1.0 );
const double y_min = 1.0;

stepper.initialize( x , t , dt );
cout << t << " " << x[0] << " " << x[1] << endl; // or some other output
t += dt;
while( t < end_time )
{
    if( t > stepper.current_time() )
    {
        // perform a real step
        stepper.do_step( ode );
    }
    else  
    {
        // perform a dense output step
        stepper.calc_state( t , x );
        cout << t << " " << x[0] << " " << x[1] << endl; // or some other output
        t += dt;
    }
    if( x[1] < y_min ) // or some other condition
    {
        cout << "Bound reached." << endl;
        break;
    }
}

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