Add CPU time output to Integrator s-Function

bmasterk · August 30, 2021, 9:36am

Hello there

You have already added the timing information of the integrator in the OCP solver. I am interested in also getting timing information about the standalone integrator (acados_sim_solver_sfunction_…), too.

Is there any way to see the CPU time for integrating the system function?

Best regards
Björn

FreyJo · August 31, 2021, 2:48pm

Hi,

I see this could be useful.

I think to implement this properly, one should first add the possibility to generate a template based integrator from a MEX acados integrator object.
Then the integrator options would be properly added to the Simulink interface.
These options are here in the template:

github.com

acados/acados/blob/348f54bb7654a7f669a28173f31264e326a1cf58/interfaces/acados_template/acados_template/c_templates_tera/acados_sim_solver.in.c#L247-L265

    
      
          {% if problem_class == "SIM" %}
              tmp_int = {{ solver_options.sim_method_num_stages }};
              sim_opts_set({{ model.name }}_sim_config, {{ model.name }}_sim_opts, "num_stages", &tmp_int);
              tmp_int = {{ solver_options.sim_method_num_steps }};
              sim_opts_set({{ model.name }}_sim_config, {{ model.name }}_sim_opts, "num_steps", &tmp_int);
          
          
    // options that are not available to AcadosOcpSolver
              //  (in OCP they will be determined by other options, like exact_hessian)
              tmp_bool = {{ solver_options.sens_forw }};
              sim_opts_set({{ model.name }}_sim_config, {{ model.name }}_sim_opts, "sens_forw", &tmp_bool);
              tmp_bool = {{ solver_options.sens_adj }};
              sim_opts_set({{ model.name }}_sim_config, {{ model.name }}_sim_opts, "sens_adj", &tmp_bool);
              tmp_bool = {{ solver_options.sens_algebraic }};
              sim_opts_set({{ model.name }}_sim_config, {{ model.name }}_sim_opts, "sens_algebraic", &tmp_bool);
              tmp_bool = {{ solver_options.sens_hess }};
              sim_opts_set({{ model.name }}_sim_config, {{ model.name }}_sim_opts, "sens_hess", &tmp_bool);
              tmp_bool = {{ solver_options.output_z }};
              sim_opts_set({{ model.name }}_sim_config, {{ model.name }}_sim_opts, "output_z", &tmp_bool);

If you use an acados integrator in your Simulink loop and think it is slow.
Adding those options and not propagating any sensitivities should accelerate that significantly.

In a second step, acados Simulink integrator options, could be added, similar to the ones of the OCP solver:

github.com

acados/acados/blob/348f54bb7654a7f669a28173f31264e326a1cf58/interfaces/acados_template/acados_template/simulink_default_opts.json

{
    "outputs": {
        "u0": 1,
        "utraj": 0,
        "xtraj": 0,
        "solver_status": 1,
        "KKT_residual": 1,
        "x1": 1,
        "CPU_time": 1,
        "CPU_time_sim": 0,
        "CPU_time_qp": 0,
        "CPU_time_lin": 0,
        "sqp_iter": 1
    },
    "inputs": {
        "lbx_0": 1,
        "ubx_0": 1,
        "parameter_traj": 1,
        "y_ref_0": 1,
        "y_ref": 1,

This file has been truncated. show original

I am not sure, if / when I will have time to implement that.
But I would encourage you to try it yourself and make a pull request.

Best,
Jonathan

bmasterk · September 2, 2021, 9:28am

Hi Jonathan,

thank you for your response

I’ll have a look and see if I can do that. So far I have seen a lot of the acados code, but not the templates yet

Best regards
Björn