JSON Format

The user can specify the instance as a JSON file. Although JSON is not the most common way to describe a MIP, it has some serious advantages. In fact it is very easy to parse it and it is trivial to write a JSON file.

Example File

{
    "min" : [1, 1],
    "constrs":[
        {"eq": [1, 1], "ge": 1},
        {"eq": [5, 10], "ge": 5},
        {"eq": [11, 5], "le": 11},
        {"eq": [11, 2], "le": 11}
    ]
}

This file describe the problem:

Minimize

• x + y

Subject to

• x + y >= 1
• 5x + 10y >= 5
• 11x + 5y <= 11
• 11x + 2y <= 11

Format

The file must describe the objective function and the constraints

Objective Function

This token describes the objective function.

KEY	VALUE	MEANING
min	list of n numbers	minimize this linear objective function
max	list of n numbers	minimize this linear objective function

Only one objective function is allowed inside an instance. Only one optimization direction is allowed.

Constraints

This token describes the constraints of the given problem. This token uses constrs as key, the value is a list of JSON object. Each object in this list describe a linear constraint. Constraints can be less or equal then or greater or equal then.

KEY	VALUE	MEANING
eq	list of n numbers	constraint linear expression - mandatory
ge	a number	constrains the eq linear expression to be greater or equal then its value
le	a number	constrains the eq linear expression to be less or equal then its value

A constraint object can contain only one of ge, le.