Abs

Expressions can contain a function that calculates the absolute value of an expression or term (function.gms).

X=abs(tt);

X=abs(y+2);

Eq1..   z=e=abs(yy);

This function is not continuous and not smooth.  It can be used on data during GAMS calculation or in models on variables or parameters.  It's use in .. equation specifications on terms involving variables requires the model type be DNLP, CNS, MCP or some other form that accepts nonsmooth functions.