How to check results in toolbox cfpde

[prudhomm]

In toolbox cfpdes, is there an export that would allow me to test/check a value?

For example, I have a calculation of a magnetic field B, I would like to compare it with the analytical value on a particular domain and that feelpp tells me in output if this test is conclusive or not (if the difference does not exceed a given error).

[prudhomm]

you can do this by adding a Checkers section in the json.
You have an example here https://github.com/feelpp/feelpp/blob/develop/toolboxes/coefficientformpdes/heat/thermo2d/thermo2d_alternative.json#L187-L196.

First you have to calculate an error between B and the exact solution in the Measures section of type Statistics or Norm and then in the Checkers section, you give the name of the calculated measure (in the example it's Statistics_dT_dt_v1_integrate) and in value you put the expected value (so 0 for you) and finally the tolerance that you grant yourself.

"Checkers":
 {
     "Measures":
      {
            "Statistics_dT_dt_v1_integrate":
              {
                   "value":"postprocess_cfpdes_measures_Statistics_dT_dt_v2_integrate:postprocess_cfpdes_measures_Statistics_dT_dt_v2_integrate",
                        "tolerance":1e-5
              }
     }
 }

Note that currently automated convergence check is not possible, you have to do it yourself by running the convergence steps