How-to: understand ponio::time_iterator#

After create a ponio::solver_range with ponio::make_solver_range() as:

24    auto sol_range = ponio::make_solver_range( f, ponio::runge_kutta::rk_33(), y0, { 0., 2.0 }, dt );

you want to create a ponio::time_iterator to loop over the solver_range

25    auto it_sol    = sol_range.begin();
26
27    while ( it_sol->time < 2.0 )
28    {
29        obs( it_sol->time, it_sol->state, it_sol->time_step );
30        ++it_sol;
31    }

The it_sol object has the following structure

@startjson #highlight ** / "type" { "type": "time_iterator", "sol": "<math>(t^n, u^n, Delta t^n)</math>", "meth": { "type": "method", "is_embedded": false, "alg": { "type": "explicit_runge_kutta", "butcher": { "type": "butcher_tableau", "A": [ "<math>[ [0, 0, 0], [1/2, 0, 0], [-1, 2, 0] ]</math>" ], "b": [ "<math>[ 1/6, 2/3, 1/6 ]</math>" ], "c": [ "<math>[ 0, 1/2, 1 ]</math>" ] }, "info": { "type": "iteration_info", "error": 0.0, "success": true, "is_step": false, "number_of_stages": 3, "number_of_eval": 3, "tolerance": 1e-5 } }, "kis": [ "<math>k_1</math>", "<math>k_2</math>", "<math>k_3</math>" ] }, "pb": "<math>f : (t,u) |-> f(t,u)</math>", "t_span": [ 0.0, 2.0 ], "it_next_time": 2.0, "dt_reference": 0.01 } @endjson

Summarize of time_iterator class#

See also

The full example can be found in how_to_solver_range.cpp.

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