Hi Anita, You are right, the constraint error is an obsolute error on the constraint. It is equal to |f(x_opt) - s| = |f(T(u_opt)) - s| where f is your code, T the inverse iso-probabilistic transformation that maps the standard space into the physical space, u_opt the design point (so in the standard space) and x_opt = T(u_opt) its image in the physical space.
Are you 100% sure that you compute f at the correct point in your verification? If you compare f(u_opt) with s, it is wrong (and I suspect that you did it ;-)). Otherwise there is a bug and we need more input from your side in order to catch it. Cheers Régis ________________________________ De : Anita Laera <[email protected]> À : [email protected] Envoyé le : Mardi 14 mars 2017 15h25 Objet : [ot-users] constraint error FORM Hi all, I have a simple question regarding the constraint error of a FORM analysis, the constraint error is defined as |f(u_n) - s| , i.e. the absolute difference between the result and the threshold. In my case, the result in the design point is 845.307471892986 and the threshold is 850 (in the physical space). I would expect the constraint error to be about 4.69, but the value obtained with the method getConstraintError() is 4.59. Why? If I calculate the difference between the result and the threshold for each performed evaluation, I never find 4.59. Could it be different because it is calculated in the standard space u? How could I verify the value? Thank you for your time! _______________________________________________ OpenTURNS users mailing list [email protected] http://openturns.org/mailman/listinfo/users _______________________________________________ OpenTURNS users mailing list [email protected] http://openturns.org/mailman/listinfo/users
