@oat-sa/tao-item-runner-qti/dist/scoring/processor/expressions/operators/lcm.js

TAO QTI Item Runner modules

define(['lodash'], function (_) { 'use strict';

    _ = _ && Object.prototype.hasOwnProperty.call(_, 'default') ? _['default'] : _;

    /*
     * This program is free software; you can redistribute it and/or
     * modify it under the terms of the GNU General Public License
     * as published by the Free Software Foundation; under version 2
     * of the License (non-upgradable).
     *
     * This program is distributed in the hope that it will be useful,
     * but WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     * GNU General Public License for more details.
     *
     * You should have received a copy of the GNU General Public License
     * along with this program; if not, write to the Free Software
     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
     *
     * Copyright (c) 2015-2019 (original work) Open Assessment Technlogies SA (under the project TAO-PRODUCT);
     *
     */

    var lcmProcessor = {

        constraints: {
            minOperand: 1,
            lcmOperand: -1,
            cardinality: ['single', 'multiple', 'ordered'],
            baseType: ['integer']
        },

        operands: [],

        /**
         * Process operands and returns the lcm.
         * @type {OperatorProcessor}
         * @exports taoQtiItem/scoring/processor/expressions/operators/lcm
         */
        process: function() {

            var result = {
                cardinality: 'single',
                baseType: 'integer'
            };
            var castedOperands;

            //if at least one operand is null or infinity, then break and return null
            if (_.some(this.operands, _.isNull) === true) {
                return null;
            }

            castedOperands = this.preProcessor.parseOperands(this.operands);

            //if at least one operand is a not a number,  then break and return null
            if (!castedOperands.every(this.preProcessor.isNumber)) {
                return null;
            }

            if (castedOperands.value().indexOf(0) !== -1) {
                result.value = 0;
                return result;
            }

            result.value = lcm(castedOperands.value());

            return result;
        }
    };

    /**
     * Calculates least common multiple for two ore more integers
     * @param {Array<number|Number>}numbers
     * @returns {number} least common multiple
     */
    function lcm(numbers) {
        var n = numbers.length,
            a = Math.abs(numbers[0]),
            b,
            c,
            i;

        for (i = 1; i < n; i++) {
            b = Math.abs(numbers[i]);
            c = a;
            while (a && b) {
                a > b ? a %= b : b %= a;
            }
            a = Math.abs(c * numbers[i]) / (a + b);
        }
        return a;
    }

    return lcmProcessor;

});