Today I got an email asking whether it’d be possible to speed up a fingerprint similarity matrix calculation in R. Now, pairwise similarity matrix calculations (whether they’re for molecules or sequences or anything else) are by definition quadratic in nature. So performing these calculations for large collections aren’t always feasible – in many cases, it’s […]
Updates to R Packages
I’ve uploaded a new version of fingerprint (v 3.4) which now supports feature fingerprints – fingerprints that are represented as variable length vectors of numbers or strings. An example would be circular fingerprints. Now, when reading fingerprints you have to indicate whether you’re loading binary fingerprints or not (via the binary argument in fp.read). A […]
A Comment on Fingerprint Performance
In a comment to my previous post on bit collisions in hashed fingerprints, Asad reported on some interesting points which would be useful to have up here: Very interesting topic. I have faced these challenges while working with fingerprints and here are few observations from my end. By the way I agree that mathematically the […]
Hashed Fingerprints and RNG’s
In my previous post I looked at how many collisions in bit positions were observed when generating hashed fingerprints (using the CDK 1024-bit hashed fingerprint and the Java hashCode method). I summarized the results in the form of “bit collision plots” where I plotted the number of times a bit was set to 1 versus […]
Path Fingerprints and Hash Quality
Recently, on an email thread I was involved in, Egon mentioned that the CDK hashed fingerprints were probably being penalized by the poor hashing provided by Java’s hashCode method. Essentially, he suspected that the collision rate was high and so that the many bits were being set multiple times by different paths and that a fraction of bits were not […]