The Graph Visualization Library Visualization is an important aid for debugging graph algorithms. MLRISC provides a simple facility for displaying graphs that adheres to the graph interface. Two graph viewer back-ends are currently supported. (An interface to the dot tool is still available but is unsupported.)

* vcg -- this tool supports the browsing of hierarchical graphs, zoom in/zoom out functions. It can handle up to around 5000 nodes in a graph.
* daVinci -- this tool supports a separate ``survey'' view from the main view and text searching. This tool is slower than vcg but it has a nicer interface, and can handle up to around 500 nodes in a graph.

All graph viewing back-ends work in the same manner. They take a graph whose nodes and edges are annotated with layout instructions and translate these layout instructions into the target description language. For vcg, the target description language is GDL. For daVinci, it is a language based on s-expressions.