JavaScript - 数学 - ベクトル - 加法、GF(2)(2元ガロア体、算術、加法、乗法)

行列プログラマー
原著

開発環境

• macOS Sierra - Apple (OS)
• Emacs (Text Editor)
• JavaScript (プログラミング言語)
• Node.js, Safari(JavaScript エンジン)
• Learning JavaScript [邦訳](参考書籍)

行列プログラマー(Philip N. Klein (著)、 松田 晃一 (翻訳)、 弓林 司 (翻訳)、 脇本 佑紀 (翻訳)、 中田 洋 (翻訳)、 齋藤 大吾 (翻訳)、オライリージャパン)の2章(ベクトル)、2.14(問題)、ベクトルの加法の練習、問題 2.14.1、2.14.2、2.14.3 を JavaScript で取り組んでみる。

課題 2.12.9

voting_record_dump109.txt

コード(Emacs)

HTML5

<pre id="output0"></pre>
<button id="run0">run</button>
<button id="clear0">clear</button>

<script src="sample14_1.js"></script>

JavaScript

let btn0 = document.querySelector('#run0'),
    btn1 = document.querySelector('#clear0'),
    pre0 = document.querySelector('#output0'),
    p = (x) => pre0.textContent += x + '\n';


let Vector = (labels, func={}) => {
    let that = {},
        d = labels,
        f = func,
        setItem = (d, val) => {
            f[d] = val;
        },
        getItem = (d) => {
            return f[d] === undefined ? 0 : f[d];
        },
        scalarMul = (a) => {
            let func = {};

            d.forEach((k) => {
                func[k] = f[k] * a;
            });
            return Vector(d, func);
        },
        add = (v) => {
            let func = {};

            d.forEach((k) => {
                func[k] = f[k] + v.getItem(k);
            });
            return Vector(d, func);
        },
        sub = (v) => that.add(v.scalarMul(-1)),
        neg = () => that.scalarMul(-1),
        dot = (v) => {
            return d.map((i) => that.getItem(i) * v.getItem(i))
                .reduce((x, y) => x + y);
        },
        isEqual = (v) => {
            return d.every((x, i) => that.getItem(i) === v.getItem(i));
        },
        toString = () => {
            return '{' +
                d.map((k) => `${k}: ${that.getItem(k)}`).join(', ') +
                '}';
        };

    that.d = () => d;
    that.f = () => f;    
    that.getItem = getItem;
    that.setItem = setItem;
    that.scalarMul = scalarMul;
    that.add = add;
    that.sub = sub;
    that.neg = neg;
    that.dot = dot;
    that.isEqual = isEqual;
    that.toString = toString;
            
    return that;
};
let arrayToVector = (a) => {
    let l = [],
        f = {};

    a.forEach((x, i) => {
        l.push(i);
        f[i] = x;
    });
    return Vector(l, f);
};

let gf2mul = (u, v) => {
    let mul = (x, y) => x === 0 || y === 0 ? 0 : 'one';
    return u.map((x, i) => mul(x, v[i]));
};
let gf2add = (u, v) => {
    let add = (x, y) => x === y ? 0 : 'one';
    return u.map((x, i) => add(x, v[i]));
};

let arrayIsEqual = (u, v) => {
    return u.map((x, i) => x === v[i])
        .every((x) => x);
};
let v = arrayToVector([-1, 3]),
    u = arrayToVector([0, 4]),
    v1 = [0, 'one', 'one'],
    u1 = ['one', 'one', 'one'];

let output = () => {
    [[v.add(u), arrayToVector([-1, 7])],
     [v.sub(u), arrayToVector([-1, -1])]]
        .forEach((a) => {
            let [left, right] = a;

            p(left.isEqual(right));
        });
    [[gf2add(v1, u1), ['one', 0, 0]],
     [gf2mul(v1, u1), [0, 'one', 'one']]]
        .forEach((a) => {
            let [left, right] = a;

            p(arrayIsEqual(left, right));
        });
};

btn0.onclick = output;
btn1.onclick = () => pre0.textContent = '';

output();