Xpress-Mosel, Linear constraint expressions

Mosel에서 linear expression을 다루는 방식에 대한 설명이다.

Internally all linear constraints are stored in the same form: a linear expression (including a constant term) and a constraint type (the right hand side is always 0). This means, the constraint expression 3*x>=5*y-10 is internally represented by: 3*x-5*y+10 and the type `greater than or equal to'. When a reference to a linear constraint appears in an expression, its value is the linear expression it contains. For example, if the identifier ctl refers to the linear constraint 3*x>=5*y-10, the expression z-x+ctl is equal to: z-2*x-5*y+10.

Note that the value of a unary constraint of the type x is_type threshold is x-threshold.

- from, FICO_TM Xpress, Xpress-Mosel Reference manual, Release 3.2, March 2011.