I believe this is closer to the thing you were asking about, and the simple answer appears to be "a home grown one in python" https://github.com/mwmbl/mwmbl/blo

I believe this is closer to the thing you were asking about, and the simple answer appears to be "a home grown one in python" https://github.com/mwmbl/mwmbl/blob/e544d45c374c13cdc1a5048dac28b3961d39e7c5/mwmbl/tinysearchengine/rank.py#L151 https://github.com/mwmbl/mwmbl/blob/e544d45c374c13cdc1a5048d...