User defined comm_group
I'd like to model a user-defined commodity group in Answer-Times.  If I'm not
wrong this option doesn't exist in the CommGroup tab. So, I can create a new
commodity called, for example, "gas-kerosene", and then A-T adds it as a CG. But how does the model know that this commodity and its corresponding comm-group are comprised of the 2 actual products, and are not just another commodity, equal to all others. Or should I be modelling the user defined commodity groups in a different way?
Thanks. Sara

I'm not sure my question was so clear, so i'll try to clarify. My ultimate goal is to define a combined share of the products in that comm_grp.
I've seen that, I could create a new comm_grp, and then define with parameter g_map which commodities are included in that group. But then, when I try to use FLO_SHAR in the process  for that combined group, it gives me the option of bounding commodities, not commodity groups.
I could create a commodity, with similar (similar, not exact) name as the comm-grp, but then i'm back to the start, how does the model know that this "commodity" is actually a kind of "combined commodity"? I'm sure I'm missing or misunderstanding something.
Thanks again. Sara
Sara, I am sorry that your question has not yet been answered.

You can actually define a commodity to be also a user-defined commodity group, but such a "Group commodity" should never be used in the topology of processes.  First, create the new commodity, and then define members for this Group commodity using COM_GMAP on the TID spread on the CommGroup Tab, with the newly created commodity selected in the top part.

After defining the member commodities for the Group commodity, you can then use the commodity on the Process tab as the constrained commodity in a FLO_SHAR parameter, and some other commodity group as the reference group.

I hope this answer helps you, although it comes so late. Embarrassed

(Note that you can also use ACTGRP as the commodity group in FLO_SHAR, for referring to the process activity).
Hi, Antti,
Thank you very much for your reply (it's better late than never, so really thank you). I understand now how it works.

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