There are two issues. (1) There is a small glitch in polymake's design of subobject properties (such as LP or MILP). The following works: > $x = lp2poly("untitled.lp"); > $obj= new Vector([1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1]); > $x->MILP(LINEAR_...