Hello everybody

At the moment I am trying to program a code for operating room scheduling .. I have one problem that one of my constraints requires to code the expression ( such as) but I do not know how to do it on OPL Cplex optimizer .. When I run the program the following message appears

[ decision variable (or expression) Fd is not authorized ]

Please look at the attached files for the Cplex code and the mathematical expression of the constraint

Bearing in mind that Fd(i) is a decision variable and dur(i) and d are parameters

It is urgent for me and thank you in advance for your kind help