comet_maths is a python module with useful mathematical algorithms (including interpolation with uncertainties) for general use as well as for use in the other tools in the CoMet toolkit. The comet_maths documentation is available here. There are also jupyter notebooks available in the example section.
There are quite a range of different functionalities within comet_maths. There are currently three submodules. One for linear algebra (mainly used for matrix operations in both obsarray and punpy), one for random generators (mainly used for sample generation in punpy) and one for interpolation (for general use).
The interpolation submodules focuses on two aspects. First, it aims to provide interpolation uncertainties that are as realistic as possible, and include both a contribution from the uncertainty on the input data point, as well as a contribution from the uncertainty in the model used for interpolation. Second, the interpolation module has functionality to interpolate between some low-resolution data points following a high resolution example. The example spectrum gets scaled in order to go through the low-resolution data points to form a sensible interpolation. For more info, see the comet_maths documentation.