Avoid if-else-end in parsevalsum/parsevalsum2

[navidcy]

Any idea how to overload the parsevalsum()/parsevalsum2() functions to avoid the if statements, e.g., here:

FourierFlows.jl/src/utils.jl

Line 110 in ca332a9

if size(uh, 1) == grid.nkr # uh is in conjugate symmetric form

?

cc @glwagner

[glwagner]

To make dispatch possible, information must be encoded via type specification.

Given an array of numbers representing a Fourier transform, there's no way to infer whether uh has the "conjugate symmetric" form or not.

Probably the right way to permit functionality like this is to use a Field abstraction (rather than just arrays) for storing data. A well-implemented Field abstraction would encode needed metadata with types, such as whether a field is real-valued in physical space.

[navidcy]

#FourierFlows v2.0

[navidcy]

Also #129

[navidcy]

But for now we can write two separate functions, eg parsevalsum and parsevalsumr.

[navidcy]

Since benchmarks in #250 didn't reveal that any benefit was gained, I'm closing this issue.