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There are many different graph layout strategies:

There are many different graph layout strategies:

有许多不同的图形布局策略:

有许多不同的图形布局方法:

*In [[force-based layout]] systems, the graph drawing software modifies an initial vertex placement by continuously moving the vertices according to a system of forces based on physical metaphors related to systems of [[spring (device)|springs]] or [[molecular mechanics]]. Typically, these systems combine attractive forces between adjacent vertices with repulsive forces between all pairs of vertices, in order to seek a layout in which edge lengths are small while vertices are well-separated. These systems may perform [[gradient descent]] based minimization of an [[energy function]], or they may translate the forces directly into velocities or accelerations for the moving vertices.<ref>{{harvtxt|Di Battista|Eades|Tamassia|Tollis|1994}}, Section 2.7, "The Force-Directed Approach", pp. 29–30, and Chapter 10, "Force-Directed Methods", pp. 303–326.</ref>

*In [[force-based layout]] systems, the graph drawing software modifies an initial vertex placement by continuously moving the vertices according to a system of forces based on physical metaphors related to systems of [[spring (device)|springs]] or [[molecular mechanics]]. Typically, these systems combine attractive forces between adjacent vertices with repulsive forces between all pairs of vertices, in order to seek a layout in which edge lengths are small while vertices are well-separated. These systems may perform [[gradient descent]] based minimization of an [[energy function]], or they may translate the forces directly into velocities or accelerations for the moving vertices.<ref>{{harvtxt|Di Battista|Eades|Tamassia|Tollis|1994}}, Section 2.7, "The Force-Directed Approach", pp. 29–30, and Chapter 10, "Force-Directed Methods", pp. 303–326.</ref>

*[[Spectral layout]] methods use as coordinates the [[eigenvector]]s of a [[Matrix (mathematics)|matrix]] such as the [[Discrete Laplace operator|Laplacian]] derived from the [[adjacency matrix]] of the graph.<ref>{{harvtxt|Beckman|1994}}; {{harvtxt|Koren|2005}}.</ref>

*[[Spectral layout]] methods use as coordinates the [[eigenvector]]s of a [[Matrix (mathematics)|matrix]] such as the [[Discrete Laplace operator|Laplacian]] derived from the [[adjacency matrix]] of the graph.<ref>{{harvtxt|Beckman|1994}}; {{harvtxt|Koren|2005}}.</ref>

'''<font color="#ff8000">频谱布局方法 Spectral Layout</font>'''使用从图的邻接矩阵派生的矩阵（例如Laplacian）的'''<font color="#ff8000">特征向量 Eigenvector</font>'''作为坐标。

'''<font color="#ff8000">频谱布局方法 Spectral Layout</font>'''，以从图的邻接矩阵派生的矩阵（例如Laplacian）的'''<font color="#ff8000">特征向量 Eigenvector</font>'''作为坐标。

*Orthogonal layout methods, which allow the edges of the graph to run horizontally or vertically, parallel to the coordinate axes of the layout. These methods were originally designed for [[VLSI]] and [[Printed circuit board|PCB]] layout problems but they have also been adapted for graph drawing. They typically involve a multiphase approach in which an input graph is planarized by replacing crossing points by vertices, a topological embedding of the planarized graph is found, edge orientations are chosen to minimize bends, vertices are placed consistently with these orientations, and finally a layout compaction stage reduces the area of the drawing.<ref>{{harvtxt|Di Battista|Eades|Tamassia|Tollis|1994}}, Chapter 5, "Flow and Orthogonal Drawings", pp. 137–170; {{harv|Eiglsperger|Fekete|Klau|2001}}.</ref>

*Orthogonal layout methods, which allow the edges of the graph to run horizontally or vertically, parallel to the coordinate axes of the layout. These methods were originally designed for [[VLSI]] and [[Printed circuit board|PCB]] layout problems but they have also been adapted for graph drawing. They typically involve a multiphase approach in which an input graph is planarized by replacing crossing points by vertices, a topological embedding of the planarized graph is found, edge orientations are chosen to minimize bends, vertices are placed consistently with these orientations, and finally a layout compaction stage reduces the area of the drawing.<ref>{{harvtxt|Di Battista|Eades|Tamassia|Tollis|1994}}, Chapter 5, "Flow and Orthogonal Drawings", pp. 137–170; {{harv|Eiglsperger|Fekete|Klau|2001}}.</ref>

*Tree layout algorithms these show a rooted [[tree structure|tree]]-like formation, suitable for [[tree (graph theory)|trees]]. Often, in a technique called "balloon layout", the children of each node in the tree are drawn on a circle surrounding the node, with the radii of these circles diminishing at lower levels in the tree so that these circles do not overlap.<ref>{{harvtxt|Herman|Melançon|Marshall|2000}}, Section 2.2, "Traditional Layout – An Overview".</ref>

*Tree layout algorithms these show a rooted [[tree structure|tree]]-like formation, suitable for [[tree (graph theory)|trees]]. Often, in a technique called "balloon layout", the children of each node in the tree are drawn on a circle surrounding the node, with the radii of these circles diminishing at lower levels in the tree so that these circles do not overlap.<ref>{{harvtxt|Herman|Melançon|Marshall|2000}}, Section 2.2, "Traditional Layout – An Overview".</ref>

*[[Layered graph drawing]] methods (often called Sugiyama-style drawing) are best suited for [[directed acyclic graph]]s or graphs that are nearly acyclic, such as the graphs of dependencies between modules or functions in a software system. In these methods, the nodes of the graph are arranged into horizontal layers using methods such as the [[Coffman–Graham algorithm]], in such a way that most edges go downwards from one layer to the next; after this step, the nodes within each layer are arranged in order to minimize crossings.<ref>{{harvtxt|Sugiyama|Tagawa|Toda|1981}}; {{harvtxt|Bastert|Matuszewski|2001}}; {{harvtxt|Di Battista|Eades|Tamassia|Tollis|1994}}, Chapter 9, "Layered Drawings of Digraphs", pp. 265–302.</ref>

*[[Layered graph drawing]] methods (often called Sugiyama-style drawing) are best suited for [[directed acyclic graph]]s or graphs that are nearly acyclic, such as the graphs of dependencies between modules or functions in a software system. In these methods, the nodes of the graph are arranged into horizontal layers using methods such as the [[Coffman–Graham algorithm]], in such a way that most edges go downwards from one layer to the next; after this step, the nodes within each layer are arranged in order to minimize crossings.<ref>{{harvtxt|Sugiyama|Tagawa|Toda|1981}}; {{harvtxt|Bastert|Matuszewski|2001}}; {{harvtxt|Di Battista|Eades|Tamassia|Tollis|1994}}, Chapter 9, "Layered Drawings of Digraphs", pp. 265–302.</ref>

*[[Dominance drawing]] places vertices in such a way that one vertex is upwards, rightwards, or both of another if and only if it is [[reachability|reachable]] from the other vertex. In this way, the layout style makes the reachability relation of the graph visually apparent.<ref>{{harvtxt|Di Battista|Eades|Tamassia|Tollis|1994}}, Section 4.7, "Dominance Drawings", pp. 112–127.</ref>

*[[Dominance drawing]] places vertices in such a way that one vertex is upwards, rightwards, or both of another if and only if it is [[reachability|reachable]] from the other vertex. In this way, the layout style makes the reachability relation of the graph visually apparent.<ref>{{harvtxt|Di Battista|Eades|Tamassia|Tollis|1994}}, Section 4.7, "Dominance Drawings", pp. 112–127.</ref>

'''<font color="#ff8000">优势图 Dominance Drawing</font>'''当且仅当一个顶点可以从另一个顶点到达时，优势画顶点的方式是:一个顶点向上，或向右，或两个顶点同时向上。这样，布局风格使得图的可达性关系在视觉上变得明显。

'''<font color="#ff8000">优势图 Dominance Drawing</font>'''当且仅当一个顶点可以从另一个顶点到达时，画顶点的最优方式是:一个顶点向上，或向右，或两个顶点同时向上。这样，布局风格使得图的可达性关系在视觉上变得明显。

==Application-specific graph drawings 专用图==

==Application-specific graph drawings 专用图==