A while back I wrote about some updates I had made to the CDK fingerprinting code to improve performance. Recently Egon and Jonathan Alvarsson (Uppsala) had made even more improvements. Some of them are simple fixes (making a String[] final, using Set rather than List) while others are more significant (efficient caching of paths). In […]
Brute Force – Inelegant, But Sometimes Useful
A few days back I posted on improving query times in Pub3D by going from a monolithic database (17M rows), to a partitioned version (~ 3M rows in 6 separate databases) and then performing queries in parallel. I also noted that we were improving query times by making use of an R-tree spatial index. Andrew […]
Java Port of VFLib Works and it’s Blazing
Sometime back I described how I was porting the VFLib algorithms to Java, so that we could use it for substructure search, since the current UniversalIsomorphismTester is pretty slow for this task, in general. While I had translated the Ullman algorithm implementation of VFLib and shown that it outperformed the CDK method, it turned out […]
Multi-threaded Database Access with Python
Pub3D contains about 17.3 million 3D structures for PubChem compounds, stored in a Postgres database. One of the things we wanted to do was 3D similarity searching and to achieve that we’ve been employing the Ballester and Graham-Richards method. In this post I’m going to talk about performance – how we went from a single […]
Faster Substructure Search in the CDK
The CDK uses the UniversalIsomorphismTester to perform graph and subgraph isomorphism. However it’s not very efficient and this shows when performing substructure searches over large collections. A quick test where I compared the CDK code to OpenBabel’s obgrep showed that the CDK is nearly forty times slower than OpenBabel. Improvements in this code will enhance […]