Number: 181
Title: neato gives up on a graph. it asks me to fill this form
Submitter: thierry ITTY
Date: Thu Aug 1 10:34:30 2002
Subsys: Neato
Version: graphviz-1.8.6.exe
System: *-*-*
Severity: critical
Problem:
neato gives up on the following graph without any more explanation it works fine without the graph attribute model=circuit it fails when this attribute is set
Input file: b181.dot
Comments:
[erg] The cause is that something goes wrong during the solution of the circuit model. neato reports this on stdout, lneato doesn't recognize a graph and gives up.

The root cause is that the graph is disconnected. The circuit model inverts the Laplacian, but this is singular for disconnected graphs.

A related problem is that, in this case, the user's graph wasn't really disconnected. He uses a node 2810_admin, which the lexer breaks in two, making the graph disconnected. The parser prints a warning but it doesn't show up in lneato in Windows.
Fix:
Catch disconnected graphs and revert to the distance model, warning the user and mentioning the pack=true option.
Owner: erg
Status: Fixed (1 August 2002)