How to return multi-dimensional results?

[gavinmacaulay]

If a model accepts vector values for input parameters (e.g., sound speed, density, frequency, incident angles, etc), we need a sensible way to specify and return the combinations of those parameters.

Some form of multi-dimensional arrays would work for this, such as in the xarray package, as would flattening things out into a table. Need to consider choosing something that is usable in other languages that may want to use or be part of echoSMs (e.g., R, Julia, Matlab).

For input parameters do we automatically model all combinations of input parameters, or provide some control over this? Could alternatively flatten these into a table (which would work nicely with having a table for the return variables). One disadvantage of a table is that computationally efficient structuring of the code is harder to do (e.g., some models can reuse partially calculated values when looping over an input parameter array).