csp's Introduction

Cutting Stock Problem

Cutting Stock Problem (CSP) deals with planning the cutting of rods from given stock items.

This implementation of CSP tries to answer
How to minimize number of stock items used while cutting customer order?
While doing so, it also optimizes for
How to cut the stock for customer orders so that waste is minimum?

Quick start

Clone this project and install required packages:

$ git clone [email protected]:jaburjak/csp.git
$ cd csp
$ python -m venv env
$ source env/bin/activate
$ pip install -r requirements.txt

Usage

To solve your Cutting Stock Problem, run the stock_cutter_1d.py file:

(env) $ python csp/stock_cutter_1d.py infile.txt

Output:

{
    "statusName": "OPTIMAL",
    "numSolutions": 1,
    "numUniqueSolutions": 1,
    "numRollsUsed": 5,
    "solutions": [
    	[
            // [unused_stock_width, [item_width...]]
            [0, [3400, 500, 500, 500, 220, 220, 220, 220, 220]],
            [80, [500, 500, 500, 500, 220, 1850, 1850]],
            [10, [220, 220, 1850, 1850, 1850]],
            [90, [3400, 220, 220, 220, 1850]],
            [880, [3400, 500, 500, 500, 220]]
        ]
    ]
}

You can use option --no-fast to use a more precise model (also slower) algorithm for calculation.

Using the input file

The first number in the input file must be the stock width followed by requested item widths. Numbers should be separated by whitespace.

Libraries

Google OR-Tools

Limitations

Works with integers only. If you have some values that have decimal part, you can multiply all of your inputs with some number that will make them integers (or close estimation).