Full horizon and cost function value from S-function

FreyJo · June 8, 2020, 2:04pm

Hi,

I am glad you like the S-function.

Did you actually edit the template?
https://github.com/acados/acados/blob/master/interfaces/acados_template/acados_template/c_templates_tera/acados_solver_sfun.in.c#L1
Or the generated Code?

I think it is a trade-off what is added as input/output to the S-function.
If all possible inputs & outputs were added, I think that the block would get hard to use and probably it would slow down Simulink.

However, please feel encouraged to extent the S-function for your needs.
For example, you can enlarge the port with x_1 to contain the full state trajectory.
For that you would have to change the size of the port here (to size N*nx).:

github.com

acados/acados/blob/a1cf26cdc27a5824114c81edc3e6410808df26a5/interfaces/acados_template/acados_template/c_templates_tera/acados_solver_sfun.in.c#L153


      
          ssSetInputPortVectorDimension(S, {{ i_input }}, {{ dims.nh }});
          {%- set i_input = i_input + 1 %}
          // uh
          ssSetInputPortVectorDimension(S, {{ i_input }}, {{ dims.nh }});
          {%- endif %}
          
          // specify dimension information for the output ports
          ssSetOutputPortVectorDimension(S, 0, {{ dims.nu }} ); // optimal input
          ssSetOutputPortVectorDimension(S, 1, 1 ); // solver status
          ssSetOutputPortVectorDimension(S, 2, 1 ); // KKT residuals
          ssSetOutputPortVectorDimension(S, 3, {{ dims.nx }} ); // first state
          ssSetOutputPortVectorDimension(S, 4, 1); // computation times
          ssSetOutputPortVectorDimension(S, 5, 1 ); // sqp iter
          
          // specify the direct feedthrough status
          // should be set to 1 for all inputs used in mdlOutputs
          {%- for i in range(end=n_inputs) %}
          ssSetInputPortDirectFeedThrough(S, {{ i }}, 1);
          {%- endfor %}
          
          // one sample time

and add a loop that extracts x for stage 1 up to N here:

github.com

acados/acados/blob/a1cf26cdc27a5824114c81edc3e6410808df26a5/interfaces/acados_template/acados_template/c_templates_tera/acados_solver_sfun.in.c#L382


      
          
              // get sqp iter
              ocp_nlp_get(nlp_config, nlp_solver, "sqp_iter", (void *) &tmp_int);
              *out_sqp_iter = (real_t) tmp_int;
          //    *out_sqp_iter = (real_t) nlp_out->sqp_iter;
          
              // get solution
              ocp_nlp_out_get(nlp_config, nlp_dims, nlp_out, 0, "u", (void *) out_u0);
          
              // get next state
              ocp_nlp_out_get(nlp_config, nlp_dims, nlp_out, 1, "x", (void *) out_x1);
          
          }
          
          static void mdlTerminate(SimStruct *S)
          {
              acados_free();
          }
          
          
          #ifdef  MATLAB_MEX_FILE

Best,
Jonathan