Support for open source solver?

[xKHUNx]

I would really love to try out this program, but installing Gurobi is a roadblock to me. Is it possible to implement this with open source solver such as GLPK or lpsolve? I don't really mind the running speed since it's a one time thing anyway.

I've tried to modify the code to work with GLPK but apparently it wasn't that straight forward:

Line 44 in transit-map/index.js

const gurobiPromise = spawn('glpsol', ['--lp', problemPath, '--write', solutionPath], {cwd})

I got this error:

GLPSOL: GLPK LP/MIP Solver, v4.65
Parameter(s) specified in the command line:
 --lp C:\...\transit-map-13672efP1odLg00j8\problem.lp
 --write C:\...\transit-map-13672efP1odLg00j8\solution.sol
Reading problem data from 'C:\...\transit-map-13672efP1odLg00j8\problem.lp'...
C:\...\transit-map-13672efP1odLg00j8\problem.lp:2: character '[' not recognized

So it seems like the .lp file format is different from Gurobi's.

Would like to hear from you.

[budul100]

First, @juliuste: Thank you for this great project! I have searched for such a solution for a while.

@xKHUNx: I have forked your project to implement a solution based on the CBC solver. Some changes were necessary for the LP generator to cover the squared edge lengths. And I have adjusted the solution parser to cover the resulting solver file.

You'll only need to load a current version of CBC.exe from the zip file and place it into the script folder.