Added normalization to functions that are not evenly sampled.

Eigenfunctions don’t seem to normalize quite correctly for wave numbers other than zero. Not sure what I’m doing wrong.
Added function to average over a range.

Attempted to implemented averaging over unevenly sampled data.

Testing random walks. Seems to work fine.
Zeroed out the eigenmodes with frequencies larger than the buoyancy frequency. This seems to resolve the last issues.