mathball/lib/matrixMultiply/index.js

A JavaScript library for Competitive Programming

'use strict';

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

var validate = require('../validation/number-array');

function dimValidation(arr) {
    var dimension = arr[0].length;
    for (var i = 1; i < arr.length; i++) {

        if (arr[i].length !== dimension) {
            return false;
        } else {
            continue;
        }
    }
    return true;
}

function multiply(arr1, arr2) {

    var noOfRows = arr1.length,
        noOfCols = arr2[0].length;
    var temp = [],
        answer = [],
        sum = 0,
        i = void 0,
        j = void 0,
        k = void 0;

    for (i = 0; i < noOfRows; i++) {
        for (j = 0; j < noOfCols; j++) {
            for (k = 0; k < arr2.length; k++) {
                sum += arr1[i][k] * arr2[k][j];
            }
            temp.push(sum);
            sum = 0;
        }
        answer.push(temp);
        temp = [];
    }

    return answer;
}

module.exports = function (arr1, arr2) {
    var _ref, _ref2;

    validate((_ref = []).concat.apply(_ref, _toConsumableArray(arr1)), 'multiply');
    validate((_ref2 = []).concat.apply(_ref2, _toConsumableArray(arr2)), 'multiply');

    if (!dimValidation(arr1) || !dimValidation(arr2) || arr1[0].length !== arr2.length) {
        return "Matrices are not compatible for multiplication";
    } else {
        return multiply(arr1, arr2);
    }
};