Graphviz：禁止水平边缘，始终显示垂直方向

Question

我有一个有向无环图，我正尝试使用 Graphviz 的 dot 对其进行可视化。默认情况下，它的布局是 top-to-bottom.

通常，所有有向边的头都低于尾巴。但在某些情况下，它们被绘制为水平直线部分，即头部和尾部处于同一水平。在我的例子中，这是在我定义子图集群之后发生的。

他们有办法禁止这种情况并强制它总是定位节点以便箭头指向"downwards"吗？

示例来源：

digraph {
  rankdir=TB;
  subgraph cluster_1 { "8"; "7"; "9"; "11"; "10" }
  subgraph cluster_2 { "3"; "4"; "5"; }

  "1" -> "3";
  "2" -> "5";
  "3" -> "6";
  "3" -> "5";
  "2" -> "8";
  "2" -> "4";
  "2" -> "3";
  "2" -> "6";
  "2" -> "7";
  "1" -> "8";
  "7" -> "8";
  "4" -> "6";
  "6" -> "10";
  "3" -> "11";
  "7" -> "10";
  "7" -> "6";
  "1" -> "2";
  "6" -> "5";
  "7" -> "9";
  "7" -> "5";
  "4" -> "5";
  "6" -> "8";
  "3" -> "4";
  "10" -> "11";
  "4" -> "11";
  "3" -> "8";
  "8" -> "9";
  "6" -> "9";
  "9" -> "10";
  "3" -> "10";
  "3" -> "7";
}

Answer 1

该行为是由固定内部节点等级的集群引起的。 'Force' 从外部边缘水平拉动节点，但对排名没有影响。

您必须避免集群或插入不可见的节点和边。

显示排名修复的最小示例

digraph {
    subgraph cluster_1 {
        1
        3
    }
    1 -> 2
    2 -> 3
}

Answer 2

我知道这是一个老问题，但我会提供这个答案以供将来参考：

您可以使用 newrank = true;，它根据 graphviz.org website 执行以下操作：

The original ranking algorithm in dot is recursive on clusters. This can produce fewer ranks and a more compact layout, but sometimes at the cost of a head node being place on a higher rank than the tail node. It also assumes that a node is not constrained in separate, incompatible subgraphs. For example, a node cannot be in a cluster and also be constrained by rank=same with a node not in the cluster.

If newrank=true, the ranking algorithm does a single global ranking, ignoring clusters. This allows nodes to be subject to multiple constraints. Rank constraints will usually take precedence over edge constraints.

因此您的来源仅更改如下：

  digraph {
      rankdir=TB;
      newrank = true;
      ...

这个例子的结果会更好：

Graphviz：禁止水平边缘，始终显示垂直方向

Graphviz: forbid horizontal edges, always show vertical orientation

graphviz

directed-acyclic-graphs