glpk.js
JavaScript/WebAssembly port of GLPK (GNU Linear Programming Kit) for browser & node. Rather than porting the complete GLPK library (including GLPSOL) this project aims at creating a simple JSON interface to setup and solve LP/MILP with JavaScript.
Install
npm install glpk.jsCode Example
const GLPK = require('glpk.js');
const glpk = GLPK();
const options = {
msglev: glpk.GLP_MSG_ALL,
presol: true,
cb: {
call: progress => console.log(progress),
each: 1
}
};
const res = glpk.solve({
name: 'LP',
objective: {
direction: glpk.GLP_MAX,
name: 'obj',
vars: [
{ name: 'x1', coef: 0.6 },
{ name: 'x2', coef: 0.5 }
]
},
subjectTo: [
{
name: 'cons1',
vars: [
{ name: 'x1', coef: 1.0 },
{ name: 'x2', coef: 2.0 }
],
bnds: { type: glpk.GLP_UP, ub: 1.0, lb: 0.0 }
},
{
name: 'cons2',
vars: [
{ name: 'x1', coef: 3.0 },
{ name: 'x2', coef: 1.0 }
],
bnds: { type: glpk.GLP_UP, ub: 2.0, lb: 0.0 }
}
]
}, options);Live Examples
glpk.js and Mixed-Integer Programming with a lot of background information:
Simple LP in the browser:
Some (slighty outdated) examples using glpk.js:
API
interface LP {
name: string,
objective: {
direction: number,
name: string,
vars: { name: string, coef: number }[]
},
subjectTo: {
name: string,
vars: { name: string, coef: number }[],
bnds: { type: number, ub: number, lb: number }
}[],
bounds?: {
name: string,
type: number,
ub: number,
lb: number
}[],
binaries?: string[],
generals?: string[],
options?: Options
}Optionally the "kind of structural variable"
- continuous variable (default)
- integer variable
- binary variable
may be specified with an array of variable names:
/* integer */
lp.generals = ['x1', 'x2'];
/* binary */
lp.binaries = ['x3', 'x4'];interface Options {
mipgap?: number, /* set relative mip gap tolerance to mipgap, default 0.0 */
tmlim?: number, /* limit solution time to tmlim seconds, default INT_MAX */
msglev?: number, /* message level for terminal output, default GLP_MSG_ERR */
presol?: boolean, /* use presolver, default true */
cb?: { /* a callback called at each 'each' iteration (only simplex) */
call(result: Result),
each: number
}
}
interface Result {
name: string;
time: number;
result: {
status: number;
z: number;
vars: {[key:string]: number};
dual?: { [key: string]: number }; /* simplex only */
};
}
interface GLPK {
/* direction */
readonly GLP_MIN: number; /* minimization */
readonly GLP_MAX: number; /* maximization */
/* type of auxiliary/structural variable: */
readonly GLP_FR: number; /* free (unbounded) variable */
readonly GLP_LO: number; /* variable with lower bound */
readonly GLP_UP: number; /* variable with upper bound */
readonly GLP_DB: number; /* double-bounded variable */
readonly GLP_FX: number; /* fixed variable */
/* message level: */
readonly GLP_MSG_OFF: number; /* no output */
readonly GLP_MSG_ERR: number; /* warning and error messages only */
readonly GLP_MSG_ON: number; /* normal output */
readonly GLP_MSG_ALL: number; /* full output */
readonly GLP_MSG_DBG: number; /* debug output */
/* solution status: */
readonly GLP_UNDEF: number; /* solution is undefined */
readonly GLP_FEAS: number; /* solution is feasible */
readonly GLP_INFEAS: number; /* solution is infeasible */
readonly GLP_NOFEAS: number; /* no feasible solution exists */
readonly GLP_OPT: number; /* solution is optimal */
readonly GLP_UNBND: number; /* solution is unbounded */
version: string; /* GLPK version */
write(lp: LP): string; /* writes problem data in CPLEX LP */
solve(lp: LP, options?: number | Options): Result /* options is either a glp message level or an options obj */
}Building
emsdk
git clone https://github.com/jvail/glpk.js.git
cd glpk.js
git submodule update --init --recursive
npm install
source ~/emsdk/emsdk_env.sh
npm run build && npm run testdocker
Uses official docker images for emscripten/emsdk.
docker build . -t glpk.js
docker run -v $PWD:/app glpk.js