Replace if statement with if expression in smoothTransition

[dhblum]

I was wondering if the following if statement in the function IBPSA.Utilities.Math.Functions.BaseClasses.smoothTransition could be replaced by the suggested if expression? This would allow its use in JModelica optimization for MPC. Namely, the model IBPSA.Fluid.MixingVolumes.BaseClasses.PartialMixingVolume if the parameter prescribedHeatFlowRate = true.

from:

algorithm 
 aX:= abs(x);
 y := a + aX*(b + aX*(c + aX*(d + aX*(e + aX*f))));
 if x < 0 then
    y := -y;
 end if;

to:

algorithm 
 aX:= abs(x);
 y := if x >= 0 then a + aX*(b + aX*(c + aX*(d + aX*(e + aX*f)))) else 
 -(a + aX*(b + aX*(c + aX*(d + aX*(e + aX*f)))));

I could submit a pull request.

[Mathadon]

fine by me, although this would require fewer operations in CasADi:

algorithm 
 aX:= abs(x);
 y := (if x >= 0 then 1 else -1) * (a + aX*(b + aX*(c + aX*(d + aX*(e + aX*f)))));

[dhblum]

Sounds good, that works too.