Calculate Weight matrix hangs indefinitely

[hvasbath]

The calculation of the Covariance matrix for a fairly small scene hangs indefinitely, for similar sized other scenes this is a matter of 2 seconds.... Where can I start debugging?

[hvasbath]

When quadtree leafs are small and when adaptive subsampling is enabled, the subsampling variable https://github.com/pyrocko/kite/blob/master/kite/ext/covariance.c#L130 becomes zero and the c-code enters an infinite loop as it iterates rows and columns with a zero increment ... https://github.com/pyrocko/kite/blob/master/kite/ext/covariance.c#L177