Varaha is a lightweight sampler that is efficient in small dimensions(10 or less). Sampler's primary focus is parameter estimation of compact binaries from the gravitational wave signals.

i) v1 is the flavour relevant to cheap likelihoods. This is described here
ii) v2 is significantly more efficient than v1 but comes with an added cost of calculating sampling density. It it relevant for more expensive likelihoods(one hundredths of a second or more). This is described here .