The implementation algorithms of InterpolatorCellConservativeLinear and average_down()

[WCMSG]

I am conducting research on interpolation algorithms. Could you please provide the implementation details for Interpolator CellConservativeLinear and average_down(), or point me to relevant references? I find it difficult to understand the algorithm from the source code.

[WeiqunZhang]

#396 (comment) This comment was on the interpolation. Hopefully it can help. As for average_down on cell centered data, we usually do $$\rho_{c} = \sum{\rho_{f} * v_{f}} / v_{c}$$, where $$v$$ is the volume of the cells.