I don't believe this is a Cadence tool (I've never heard of it). Do you have a reference to it?
Title of the publication: Developing DRC Plus Rules through 2D Pattern Extraction and Clustering Techniques
Authors: Vito Dai, Luigi Capodieci, Jie Yang, Norma Rodriguez,
Go to references (last page), it is the 6th reference:
Eclair- V2 Pattern Matcher User's Guide, Documentation Version 2.4, Cadence Design Systems, Inc., June 2008.
OK, I did a bit more searching and I think it is part of the LPA tools (Litho) which come in the MVS stream. I don't think it's a standalone product. I couldn't find that manual any more - it may have been in older releases of the tools. Still, not really my area.
Probably you should contact Cadence Customer Support to investigate this further.