Array Context: do inputs to call_loopy need to be thawed?

[inducer]

Not currently defined.

cc @kaushikcfd

[inducer]

I'm not sure. For arithmetic, I think requiring thawing makes sense. For call_loopy, the array context is supplied (as the self argument to call_loopy), so it's less clear that it's needed.

[inducer]

For the PyOpenCL array context, passing an un-thawed array is hypothetically fine: It's a constant array that doesn't have a queue.

For the lazy array context, we could define passing an un-thawed array as implicitly producing a DataWrapper, with similar semantics.

[inducer]

@kaushikcfd, what do you think?

[kaushikcfd]

Agree with the proposal that frozen read-only array inputs should be thawed inside call_loopy. It doesn't introduce any performance hits and provides a more convenient interface.

[inducer]

frozen read-only array inputs should be thawed inside call_loopy

What is "thawing" to you anyway, in this instance? (Remember we're trying to define semantics here IMO: It's not a given what that means.) To me: thawing in CL means "add a queue", thawing in lazy means... hm... stick in a DataWrapper. Maybe thaw is what I wanted anyay. :)

[kaushikcfd]

I thought the semantics for "thaw"-ing lazy arrays was already defined in #104. The same can be transmitted to the thawing in the context of call_loopy, which I believe is reasonable.

[inducer]

Fair.

I guess the main question then is whether we'll require the user to explicitly thaw, or whether we'll implicitly do what's necessary in call_loopy. FWIW, IMO if we do anything implicitly, we should only do so for read-only arrays.

Upside of implicit treatment:

• Convenience

Downside of implicit treatment:

• We may wind up with a few separate DataWrappers for the same data. (that are, however, pretty straightforward to clean up)

[kaushikcfd]

I vote for the implicit treatment. I think the benefits of a cleaner interface outweigh the downsides of a polluted pt.Namespace().

[inducer]

OK, implicit is good by me. Ready to close?

[kaushikcfd]

Yep, resolved from my end too.