Re-running a DICE

[ankostis]

We are opening this issue for public discussion on when it is allowed to re-run a DICE, and how.
The two reasons for doing that are:

1. to extend the Interpolation Family to Higher/Lower vehicles, and
2. to correct WLTP data (corrupted or mistaken) or NEDC's CO2 declared-values.

(please reply below if you see is another reason)

In general we suggest to avoid re-dicing, because on every dice,
the sampling decision must be respected (possibly re-testing the vehicle in WLTP/NEDC),
and consequently, the verification-factors must be updated.

So far CLIMA has approved a single re-certification, based on reason no-1.
That was a clear case involving a new physical WLTP test.
For that, JRC implemented the --recertify feature of CO2MPAS in v1.7.3post0,
which preserves the link between both runs, but only the last one is considered "ofrficial".
Of course, re-dicing after the vehicle has been put in circulation would complicate things.

We have also forward requests regarding no-2 to CLIMA
(errors in the inputs, with or without performing new physical WLTP-tests),
and we will explain here the general outcome (criteria, rules applied).

[ankostis]

As a general note, there is no universal answer for re-dicing,
every case is different.
In order to understand every such case we need
the following information:

1. Which is the Interpolation Family ID involved;
   What was the CO2MPAS deviation and the random number from the DICE?
2. Did the vehicle actually undergo a physical NEDC test?
   Do you still have the vehicle available?
3. What was the "problem" requiring a fix?
4. Would a possible fix affect the CO2MPAS deviation? (Up or down??)
5. What do you want to change?
   • the declared values?
   • wltp series?
   • road-loads?
   • something else?

You should be aware that a possible fix still needs to be DICEd.
So in principle, the vehicle has to be available for a physical test before re-dicing.

And since it is CLIMA that decides, we suggest to always send an e-mail to CLIMA
with the above questions answered, and JRC in CC.