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RDKit Fingerprint node MACCs keys gives wrong number of bits

Member for

4 years 4 months

Hi Everyone,

I'm producing MACCs keys with the "RDKit Fingerprint" node, and I am noticing that I am getting 167 bits instead of 166. The node description acknowledges that there should be 166 bits for MACCs. Not sure where this extra bit could be coming from.

Also, the "Fingerprints" node (from CDK) gives the correct number of bits.

Does anyone know where I might be able to learn more about and/or fix this issue?


Wed, 10/25/2017 - 08:07

Member for

13 years 5 months



This is an implementation detail. KNIME (and Java, and C, and Python, and ...) number bits starting at zero. In order to allow the original numbering of the MACCS keys to be used, the fingerprints need to be 167 bits long. Bit 0 should always be zero.

We can/should update the documentation for the node.