30,371 research outputs found

    Incremental Grid-like Layout Using Soft and Hard Constraints

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    We explore various techniques to incorporate grid-like layout conventions into a force-directed, constraint-based graph layout framework. In doing so we are able to provide high-quality layout---with predominantly axis-aligned edges---that is more flexible than previous grid-like layout methods and which can capture layout conventions in notations such as SBGN (Systems Biology Graphical Notation). Furthermore, the layout is easily able to respect user-defined constraints and adapt to interaction in online systems and diagram editors such as Dunnart.Comment: Accepted to Graph Drawing 201

    Upward Three-Dimensional Grid Drawings of Graphs

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    A \emph{three-dimensional grid drawing} of a graph is a placement of the vertices at distinct points with integer coordinates, such that the straight line segments representing the edges do not cross. Our aim is to produce three-dimensional grid drawings with small bounding box volume. We prove that every nn-vertex graph with bounded degeneracy has a three-dimensional grid drawing with O(n3/2)O(n^{3/2}) volume. This is the broadest class of graphs admiting such drawings. A three-dimensional grid drawing of a directed graph is \emph{upward} if every arc points up in the z-direction. We prove that every directed acyclic graph has an upward three-dimensional grid drawing with (n3)(n^3) volume, which is tight for the complete dag. The previous best upper bound was O(n4)O(n^4). Our main result is that every cc-colourable directed acyclic graph (cc constant) has an upward three-dimensional grid drawing with O(n2)O(n^2) volume. This result matches the bound in the undirected case, and improves the best known bound from O(n3)O(n^3) for many classes of directed acyclic graphs, including planar, series parallel, and outerplanar

    Improving Search-Based Schematic Layout by Parameter Manipulation

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    This paper reports on a method to improve the automated layout of schematic diagrams by widening the search space examined by the system. In search-based layout methods there are typically a number of parameters that control the search algorithm which do not affect the fitness function, but nevertheless have an impact on the final layout. We explore how varying three parameters (grid spacing, the starting distance of allowed node movement and the number of iterations) affects the resultant diagram in a hill- climbing layout system. Using an iterative process, we produce diagram layouts that are significantly better than those produced by ad-hoc parameter settings

    Optimizing an Organized Modularity Measure for Topographic Graph Clustering: a Deterministic Annealing Approach

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    This paper proposes an organized generalization of Newman and Girvan's modularity measure for graph clustering. Optimized via a deterministic annealing scheme, this measure produces topologically ordered graph clusterings that lead to faithful and readable graph representations based on clustering induced graphs. Topographic graph clustering provides an alternative to more classical solutions in which a standard graph clustering method is applied to build a simpler graph that is then represented with a graph layout algorithm. A comparative study on four real world graphs ranging from 34 to 1 133 vertices shows the interest of the proposed approach with respect to classical solutions and to self-organizing maps for graphs

    A Distributed Multilevel Force-directed Algorithm

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    The wide availability of powerful and inexpensive cloud computing services naturally motivates the study of distributed graph layout algorithms, able to scale to very large graphs. Nowadays, to process Big Data, companies are increasingly relying on PaaS infrastructures rather than buying and maintaining complex and expensive hardware. So far, only a few examples of basic force-directed algorithms that work in a distributed environment have been described. Instead, the design of a distributed multilevel force-directed algorithm is a much more challenging task, not yet addressed. We present the first multilevel force-directed algorithm based on a distributed vertex-centric paradigm, and its implementation on Giraph, a popular platform for distributed graph algorithms. Experiments show the effectiveness and the scalability of the approach. Using an inexpensive cloud computing service of Amazon, we draw graphs with ten million edges in about 60 minutes.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016
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