眠くて英語読む気しないから，d3のForceLayoutのメソッドの値を変えひたすら試し続けてメソッドの意味を調べていった話


d3.js初心者です．
よくjqueryと似ている！なんていう話をネットで見ますが，自分はjqueryもよく知らないので，ひたすら値を変えてメソッドの役割を自分なりにまとめていきます．

説明書的な英語読まずに書いていくので意味がバカっぽくなるかもしれません

## 初期状態
### サンプルコード
`<script></script>`を抜粋

```js:ForceLayout.html
<script type="text/javascript">

        var miserables = {
          "nodes":[
            {"name":"Myriel","group":1},
            {"name":"Napoleon","group":1},
            {"name":"Mlle.Baptistine","group":1},
            {"name":"Mme.Magloire","group":1},
            {"name":"CountessdeLo","group":1},
            {"name":"Geborand","group":1},
            {"name":"Champtercier","group":1},
            {"name":"Cravatte","group":1},
            {"name":"Count","group":1},
            {"name":"OldMan","group":1},
            {"name":"Labarre","group":2},
            {"name":"Valjean","group":2},
            {"name":"Marguerite","group":3},
            {"name":"Mme.deR","group":2},
            {"name":"Isabeau","group":2},
            {"name":"Gervais","group":2},
            {"name":"Tholomyes","group":3},
            {"name":"Listolier","group":3},
            {"name":"Fameuil","group":3},
            {"name":"Blacheville","group":3},
            {"name":"Favourite","group":3},
            {"name":"Dahlia","group":3},
            {"name":"Zephine","group":3},
            {"name":"Fantine","group":3},
            {"name":"Mme.Thenardier","group":4},
            {"name":"Thenardier","group":4},
            {"name":"Cosette","group":5},
            {"name":"Javert","group":4},
            {"name":"Fauchelevent","group":0},
            {"name":"Bamatabois","group":2},
            {"name":"Perpetue","group":3},
            {"name":"Simplice","group":2},
            {"name":"Scaufflaire","group":2},
            {"name":"Woman1","group":2},
            {"name":"Judge","group":2},
            {"name":"Champmathieu","group":2},
            {"name":"Brevet","group":2},
            {"name":"Chenildieu","group":2},
            {"name":"Cochepaille","group":2},
            {"name":"Pontmercy","group":4},
            {"name":"Boulatruelle","group":6},
            {"name":"Eponine","group":4},
            {"name":"Anzelma","group":4},
            {"name":"Woman2","group":5},
            {"name":"MotherInnocent","group":0},
            {"name":"Gribier","group":0},
            {"name":"Jondrette","group":7},
            {"name":"Mme.Burgon","group":7},
            {"name":"Gavroche","group":8},
            {"name":"Gillenormand","group":5},
            {"name":"Magnon","group":5},
            {"name":"Mlle.Gillenormand","group":5},
            {"name":"Mme.Pontmercy","group":5},
            {"name":"Mlle.Vaubois","group":5},
            {"name":"Lt.Gillenormand","group":5},
            {"name":"Marius","group":8},
            {"name":"BaronessT","group":5},
            {"name":"Mabeuf","group":8},
            {"name":"Enjolras","group":8},
            {"name":"Combeferre","group":8},
            {"name":"Prouvaire","group":8},
            {"name":"Feuilly","group":8},
            {"name":"Courfeyrac","group":8},
            {"name":"Bahorel","group":8},
            {"name":"Bossuet","group":8},
            {"name":"Joly","group":8},
            {"name":"Grantaire","group":8},
            {"name":"MotherPlutarch","group":9},
            {"name":"Gueulemer","group":4},
            {"name":"Babet","group":4},
            {"name":"Claquesous","group":4},
            {"name":"Montparnasse","group":4},
            {"name":"Toussaint","group":5},
            {"name":"Child1","group":10},
            {"name":"Child2","group":10},
            {"name":"Brujon","group":4},
            {"name":"Mme.Hucheloup","group":8}
          ],
          "links":[
            {"source":1,"target":0,"value":1},
            {"source":2,"target":0,"value":8},
            {"source":3,"target":0,"value":10},
            {"source":3,"target":2,"value":6},
            {"source":4,"target":0,"value":1},
            {"source":5,"target":0,"value":1},
            {"source":6,"target":0,"value":1},
            {"source":7,"target":0,"value":1},
            {"source":8,"target":0,"value":2},
            {"source":9,"target":0,"value":1},
            {"source":11,"target":10,"value":1},
            {"source":11,"target":3,"value":3},
            {"source":11,"target":2,"value":3},
            {"source":11,"target":0,"value":5},
            {"source":12,"target":11,"value":1},
            {"source":13,"target":11,"value":1},
            {"source":14,"target":11,"value":1},
            {"source":15,"target":11,"value":1},
            {"source":17,"target":16,"value":4},
            {"source":18,"target":16,"value":4},
            {"source":18,"target":17,"value":4},
            {"source":19,"target":16,"value":4},
            {"source":19,"target":17,"value":4},
            {"source":19,"target":18,"value":4},
            {"source":20,"target":16,"value":3},
            {"source":20,"target":17,"value":3},
            {"source":20,"target":18,"value":3},
            {"source":20,"target":19,"value":4},
            {"source":21,"target":16,"value":3},
            {"source":21,"target":17,"value":3},
            {"source":21,"target":18,"value":3},
            {"source":21,"target":19,"value":3},
            {"source":21,"target":20,"value":5},
            {"source":22,"target":16,"value":3},
            {"source":22,"target":17,"value":3},
            {"source":22,"target":18,"value":3},
            {"source":22,"target":19,"value":3},
            {"source":22,"target":20,"value":4},
            {"source":22,"target":21,"value":4},
            {"source":23,"target":16,"value":3},
            {"source":23,"target":17,"value":3},
            {"source":23,"target":18,"value":3},
            {"source":23,"target":19,"value":3},
            {"source":23,"target":20,"value":4},
            {"source":23,"target":21,"value":4},
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            {"source":23,"target":11,"value":9},
            {"source":24,"target":23,"value":2},
            {"source":24,"target":11,"value":7},
            {"source":25,"target":24,"value":13},
            {"source":25,"target":23,"value":1},
            {"source":25,"target":11,"value":12},
            {"source":26,"target":24,"value":4},
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            {"source":26,"target":16,"value":1},
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            {"source":27,"target":25,"value":5},
            {"source":27,"target":24,"value":1},
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            {"source":28,"target":27,"value":1},
            {"source":29,"target":23,"value":1},
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            {"source":29,"target":11,"value":2},
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            {"source":31,"target":27,"value":1},
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            {"source":38,"target":29,"value":1},
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            {"source":42,"target":25,"value":2},
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            {"source":44,"target":28,"value":3},
            {"source":44,"target":11,"value":1},
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            {"source":48,"target":25,"value":1},
            {"source":48,"target":27,"value":1},
            {"source":48,"target":11,"value":1},
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            {"source":50,"target":24,"value":1},
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            {"source":51,"target":26,"value":2},
            {"source":51,"target":11,"value":2},
            {"source":52,"target":51,"value":1},
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            {"source":53,"target":51,"value":1},
            {"source":54,"target":51,"value":2},
            {"source":54,"target":49,"value":1},
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            {"source":55,"target":49,"value":12},
            {"source":55,"target":39,"value":1},
            {"source":55,"target":54,"value":1},
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            {"source":55,"target":11,"value":19},
            {"source":55,"target":16,"value":1},
            {"source":55,"target":25,"value":2},
            {"source":55,"target":41,"value":5},
            {"source":55,"target":48,"value":4},
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            {"source":58,"target":27,"value":6},
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            {"source":62,"target":60,"value":3},
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            {"source":63,"target":60,"value":2},
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            {"source":64,"target":62,"value":12},
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            {"source":65,"target":48,"value":3},
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            {"source":65,"target":58,"value":5},
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            {"source":65,"target":60,"value":2},
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            {"source":66,"target":59,"value":1},
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            {"source":66,"target":65,"value":2},
            {"source":66,"target":48,"value":1},
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            {"source":67,"target":57,"value":3},
            {"source":68,"target":25,"value":5},
            {"source":68,"target":11,"value":1},
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            {"source":68,"target":41,"value":1},
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            {"source":69,"target":11,"value":1},
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            {"source":69,"target":27,"value":2},
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            {"source":69,"target":41,"value":1},
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            {"source":70,"target":69,"value":4},
            {"source":70,"target":68,"value":4},
            {"source":70,"target":11,"value":1},
            {"source":70,"target":24,"value":1},
            {"source":70,"target":27,"value":1},
            {"source":70,"target":41,"value":1},
            {"source":70,"target":58,"value":1},
            {"source":71,"target":27,"value":1},
            {"source":71,"target":69,"value":2},
            {"source":71,"target":68,"value":2},
            {"source":71,"target":70,"value":2},
            {"source":71,"target":11,"value":1},
            {"source":71,"target":48,"value":1},
            {"source":71,"target":41,"value":1},
            {"source":71,"target":25,"value":1},
            {"source":72,"target":26,"value":2},
            {"source":72,"target":27,"value":1},
            {"source":72,"target":11,"value":1},
            {"source":73,"target":48,"value":2},
            {"source":74,"target":48,"value":2},
            {"source":74,"target":73,"value":3},
            {"source":75,"target":69,"value":3},
            {"source":75,"target":68,"value":3},
            {"source":75,"target":25,"value":3},
            {"source":75,"target":48,"value":1},
            {"source":75,"target":41,"value":1},
            {"source":75,"target":70,"value":1},
            {"source":75,"target":71,"value":1},
            {"source":76,"target":64,"value":1},
            {"source":76,"target":65,"value":1},
            {"source":76,"target":66,"value":1},
            {"source":76,"target":63,"value":1},
            {"source":76,"target":62,"value":1},
            {"source":76,"target":48,"value":1},
            {"source":76,"target":58,"value":1}
          ]
        }


        var width = 960;
        var height = 500;

        var color = d3.scale.category20();

        var force = d3.layout.force()
          .size([width, height])
          .nodes(miserables.nodes)
          .links(miserables.links)
          .start();

        var svg = d3.select("body").append("svg")
          .attr("width", width)
          .attr("height", height);


        var link = svg.selectAll(".link")
            .data(miserables.links)
          .enter().append("line")
            .attr("class", "link")
            .style("stroke-width", function(d) { return Math.sqrt(d.value); });

        var node = svg.selectAll(".node")
            .data(miserables.nodes)
          .enter().append("circle")
            .attr("class", "node")
            .attr("r", 5)
            .style("fill", function(d) { return color(d.group); })
            .call(force.drag);

        node.append("title")
            .text(function(d) { return d.name; });

        force.on("tick", function() {
          link.attr("x1", function(d) { return d.source.x; })
              .attr("y1", function(d) { return d.source.y; })
              .attr("x2", function(d) { return d.target.x; })
              .attr("y2", function(d) { return d.target.y; });

          node.attr("cx", function(d) { return d.x; })
              .attr("cy", function(d) { return d.y; });
        });
    </script>
```

### 初期のグラフ
![スクリーンショット 2016-02-02 18.12.14.png](https://qiita-image-store.s3.amazonaws.com/0/84299/bf801f21-0615-0176-5cb9-920955660938.png "スクリーンショット 2016-02-02 18.12.14.png")
密集してる感がある

##変更を加えていく

変更を加えるのは以下だけ

```js:ForceLayoutのとこだけ！
var force = d3.layout.force()
          .size([width, height])
          .nodes(miserables.nodes)
          .links(miserables.links)
          .start();
```

`.links()`と`.start()`の間にメソッドを入れ替えて変化を調査していく．

メソッドの説明は読まないけど，[wiki](https://github.com/mbostock/d3/wiki/Force-Layout)のメソッド一覧みたいなものを試していく

```js:メソッド一覧みたいなやつ
var force = d3.layout.force()
    .nodes(nodes)
    .links(links)
    .size([w, h])
    .linkStrength(0.1)
    .friction(0.9)
    .linkDistance(20)
    .charge(-30)
    .gravity(0.1)
    .theta(0.8)
    .alpha(0.1)
    .start();
```

### linkStrength()

0~1までの値を取るらしい，そしてdefaultは0.9らしい
(すでに説明読んでるけど...)

#### min=0
![スクリーンショット 2016-02-02 18.21.45.png](https://qiita-image-store.s3.amazonaws.com/0/84299/59f1852d-e2ad-a927-7489-b255393c19dd.png "スクリーンショット 2016-02-02 18.21.45.png")

default=0.9の初期のグラフに比べてノード間の引力？的なものが弱まった印象

### friction()
0~1までの値を取るらしい，そしてdefaultは0.9らしい

#### min = 0
![スクリーンショット 2016-02-02 18.25.25.png](https://qiita-image-store.s3.amazonaws.com/0/84299/c67d45e2-4e44-63ec-9a3e-24adb74f8ff9.png "スクリーンショット 2016-02-02 18.25.25.png")

default=0.9にめっちゃキュってなった
frictionって摩擦だよなと思い，max=1にして実行したところめっちゃ動きました
スクショじゃ表現できないから割愛
キュってなった原因はちょっとわからない

### linkDistance()
default = 20

#### 100でやってみた
![スクリーンショット 2016-02-02 18.38.20.png](https://qiita-image-store.s3.amazonaws.com/0/84299/f3497cfa-8289-8b3e-3063-56453da0afc9.png "スクリーンショット 2016-02-02 18.38.20.png")

リンクが長くなった

#### 0でやってみた
ノードがくっつく勢いになりました
スクショ割愛

### charge()
default=-30なことはわかった

#### 0でやってみた
![スクリーンショット 2016-02-02 18.32.22.png](https://qiita-image-store.s3.amazonaws.com/0/84299/cc3f16b4-770e-dd9d-e15a-ef2bea1afccf.png "スクリーンショット 2016-02-02 18.32.22.png")

またキュってなった
さっぱりわからないっす．．．

### gravity()
default=0.1

#### 1でやってみた
今までは1つのノードを動かすとみんなついてきたのに，ついてこなくなった

### theta()
default=0.9

リンクされてないノードとの角度書いてたと思う

### alpha
#### 0.1でやってみた
![スクリーンショット 2016-02-02 18.50.26.png](https://qiita-image-store.s3.amazonaws.com/0/84299/4eab8bf7-563b-5118-a67e-0bfece95b40f.png "スクリーンショット 2016-02-02 18.50.26.png")

#### 2でやってみた
![スクリーンショット 2016-02-02 18.51.29.png](https://qiita-image-store.s3.amazonaws.com/0/84299/d3b3caf9-f4aa-fd9f-8300-1b7f63a2a8b7.png "スクリーンショット 2016-02-02 18.51.29.png")

値が大きい方が違うグループがかぶる率が高い気がする．

## サンプルに手を加えてみた
この記事で利用している[サンプル](http://bl.ocks.org/mbostock/4062045)に手を加えた

ノードがゆらゆら動いてしまうのを解消し，ドラッグされたノードはピン留め？できるようにした．

[Gist](https://gist.github.com/shu920921/300ccfeb8cdef8012eac)に公開しましたのでよろしければどうぞ

## おわりに
誰か一人でもこの記事で救われる人がいたら幸いですwww