PAC model: improve robusteness of detection of non-optimising agents part
BinaryOpNode::getPacNonOptimizingPart() is not sufficiently robust. It may fail for expressions of the form
(1-optim_share)*A*B, if the preprocessor reorders the factors.
This can be reproduced with
tests/pac/trend-component-2-mce/example_det.mod, by replacing
beta as a 2nd factor) in equation
The solution is probably to create a new method
ExprNode::decomposeMultiplicativeFactors() (similarly to
ExprNode::decomposeAdditiveTerms()), and use it for detecting the non-optimising part.