Float constraints

When modeled in OPL, they are restricted to be linear or piecewise linear. OPL has efficient algorithms for solving linear, piecewise linear, quadratic, or logical constraints, but in general these algorithms do not apply to nonlinear problems. Note that the linearity requirement precludes the use of relations with variables in constraints and the use of non-ground expressions as indices of float arrays. In addition, operators !=, <, and > are not allowed for float constraints. However, integers and integer variables may occur in a float constraint, provided that the constraint remains linear or quadratic. OPL supports all the expressions supported by CPLEX, provided that the constraint is of one of the types described at the beginning of this paragraph.