Linear Program Format

Structure

The linear program file consists of optional objective function, constraints, and variable declarations.

Variables

Variables are case sensitive and can have letters [A-Z],[a-z], numbers and underscore '_'. A variable must start with an underscore or a letter.

Constant Numbers

Constant can be integers or real numbers. Real numbers must be of form 123.45 .

Expressions

Allowed operators are +, -, *, /. Also parentheses ( ) can be used Expressions must be a linear combination of variables. For example (2*x + 3*y)/3 + (2*4 + 5)*z is legal, but x*(y+2) is not.

Objective function

Objective function is of the form "maximize <expression>;" or "minimize <expression>;"

Constraints

A constraint is of the form "<expression> <operator> <expression>;", where operator can be one of <=, >=, =.

Declarations

A declaration of the form "int <var1>,<var>;" states that variable should be an unsigned integer. A declaration of the form "signed int <var1>,<var>;" states that variable should be an integer.

Example file

minimize x + 2*y + 3*(z + 2*w);
x + 2 >= y;
y <= z*3+w;
w = x+z;
int x,y;
signed int w;