lml-main
Version:
This is now a mono repository published into many standalone packages.
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JavaScript
;
var flatten = require('../../utils/array').flatten;
function factory (type, config, load, typed) {
var index = load(require('../../type/matrix/MatrixIndex'));
var matrix = load(require('../../type/matrix/DenseMatrix'));
var size = load(require('../matrix/size'));
var subset = load(require('../matrix/subset'));
var compareNatural = load(require('../relational/compareNatural'));
/**
* Create the cartesian product of two (multi)sets.
* Multi-dimension arrays will be converted to single-dimension arrays before the operation.
*
* Syntax:
*
* math.setCartesian(set1, set2)
*
* Examples:
*
* math.setCartesian([1, 2], [3, 4]); // returns [[1, 3], [1, 4], [2, 3], [2, 4]]
*
* See also:
*
* setUnion, setIntersect, setDifference, setPowerset
*
* @param {Array | Matrix} a1 A (multi)set
* @param {Array | Matrix} a2 A (multi)set
* @return {Array | Matrix} The cartesian product of two (multi)sets
*/
var setCartesian = typed('setCartesian', {
'Array | Matrix, Array | Matrix': function (a1, a2) {
if (subset(size(a1), new index(0)) === 0 || subset(size(a2), new index(0)) === 0) { // if any of them is empty, return empty
var result = [];
}
else {
var b1 = flatten(Array.isArray(a1) ? a1 : a1.toArray()).sort(compareNatural);
var b2 = flatten(Array.isArray(a2) ? a2 : a2.toArray()).sort(compareNatural);
var result = [];
for (var i=0; i<b1.length; i++) {
for (var j=0; j<b2.length; j++) {
result.push([b1[i], b2[j]]);
}
}
}
// return an array, if both inputs were arrays
if (Array.isArray(a1) && Array.isArray(a2)) {
return result;
}
// return a matrix otherwise
return new matrix(result);
}
});
return setCartesian;
}
exports.name = 'setCartesian';
exports.factory = factory;