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[Václav Šmilauer <eu@xxxxxxxx>]

> can I use the MatchMaker to get the harm average of alphas parameter? 
> I am not sure to understand how it works.
> Cheers, Chiara
Hi, yes you can... You will turn (if we speak about 
Ip2_2xCohFrictMat_CohFrictPhys) alphaKr, alphaKts into MatchMaker 
objects, which will by default return constant value (so that older code 
behaves the same), something like (see also 
Ip2_FrictMat_FrictMat_FrictPhys):

((shared_ptr<MatchMaker>,alphaKr,new MatchMaker(2.0),,"docs"))

where the "new MatchMaker(2.0)" will construct new object always 
returning 2.0 [note: I will be adding this ctor, since you gave me the 
idea, now, so you will need to update]. In the code then, you will get 
the value as (*alphaKr)(mat1->id,mat2->id,mat1->alphaKr,mat2->alphaKr) 
(alphaKr is a pointer, so once needs the *). To use harmonic average 
between mat1->alphaKr and mat2->alphaKr (of which value are ignored the 
MatchMaker returns a const value), you do in the python script

  
Ip2_2xCohFrictMat_CohFrictPhys(...,alphaKr=MatchMaker(fallback='harmAvg'),...)

and that's it. One can still set the constant with

  Ip2_2xCohFrictMat_CohFrictPhys(...,alphaKr=2.0)

There is one margin case that you must handle in the c++ code, and that 
is if the shared_ptr<MatchMaker> is NULL pointer (is someone says in 
python alphaKr=None), then throw exception or something similar.

Cheers, v.