battleship-search

maximize an n-dimensional landscape using the battleship search algorithm

example

1-dimensional

var search = require('battleship-search');
var q = search([ [ 0, 5 ] ], function (pt, cb) {
    var x = pt[0];
    cb(
        Math.sin(5 * x) - Math.cos(x)
        + 1/4 * Math.sin(x - 1) - 2 * Math.cos(x)
    );
});

q.on('max', function (pt, x) {
    console.log('MAX', pt, x);
});

q.start();

output:

MAX [ 2.5 ] 2.586482695940614
MAX [ 3.125 ] 3.2950351120302708
MAX [ 2.8125 ] 4.078954538271598
MAX [ 2.890625 ] 4.093839145038978
MAX [ 2.8515625 ] 4.107647760472744
MAX [ 2.861328125 ] 4.108143493735451
MAX [ 2.8564453125 ] 4.108227683718651
MAX [ 2.85888671875 ] 4.108268474284235
MAX [ 2.857666015625 ] 4.108268817327394
MAX [ 2.8582763671875 ] 4.108273828324046
MAX [ 2.858257293701172 ] 4.1082738286448475
MAX [ 2.858266830444336 ] 4.108273829749719
MAX [ 2.8582656383514404 ] 4.10827382975
^C

4-dimensional example

var search = require('battleship-search');
var domain = [ [ -5, 5 ], [ -5, 5 ], [ -5, 5 ], [ -5, 5 ] ];

var q = search(domain, function (pt, cb) {
    var x = pt[0], y = pt[1], z = pt[2], w = pt[3];
    cb(
        Math.sin(x + y * Math.cos(z) / 10)
        + Math.sin(3 * y) - Math.cos(z + x) * 1/2
        + Math.sin(5 * w) * Math.sin(3 * x + 4 * w) * 1/8
    );
});

q.on('max', function (pt, x) {
    console.log('MAX', pt, x);
});

q.start();

output:

MAX [ -5, 5, -5, 5 ] 2.0750809293428523
MAX [ 1.25, -3.75, -3.75, 1.25 ] 2.365703195960478
MAX [ 1.25, -3.75, -3.75, 3.75 ] 2.369529012327853
MAX [ 1.25, -3.75, -3.75, -3.75 ] 2.3803181691252
MAX [ 2.03125, 0.46875, 1.40625, 0.15625 ] 2.3943124663892474
MAX [ 2.03125, 0.46875, 1.40625, 0.46875 ] 2.4460672123039338
^C

methods

var search = require('battleship-search')

var q = search(bounds, testFn)

Create a new search from an array of 2-element arrays bounds with [min,max] bounds for each dimension.

testFn(pt, cb) fires for each point pt to test. testFn() should call cb() with its result.

q.start()

Start the search. The search goes on forever until stopped.

q.stop()

Stop the search.

events

q.on('test', function (pt, value) {})

Each time the test function produces a result, the 'test' event fires with the coordinate tested pt and the resulting value.

q.on('max', function (pt, value) {})

Each time a test value is greater than the maximum value seen so far, the 'max' event fires with the point pt and the value.

install

With npm do:

npm install battleship-search

license

MIT

bingeboy / battleship-search Goto Github PK