Improve RefineFlatIndex

[ava57r]

No description provided.

[ava57r]

I revert your suggestion commits.
there required generic impl trait.

[Enet4]

If making this impl generic is absolutely necessary, please use type parameter names which does not clash with existing types.

Suggested change

	impl<IndexImpl> FromInnerPtr for PreTransformIndexImpl<IndexImpl> {
	impl FromInnerPtr for PreTransformIndexImpl<IndexImpl> {

[ava57r]

It's existing type IndexImpl.

[Enet4]

Hmm. In that case it should be this, no? (note the lack of type parameters)

impl FromInnerPtr for PreTransformIndexImpl<IndexImpl> {

[ava57r]

It does not work. It needs type parameter

[ava57r]

We tried it a07ca9b

[Enet4]

OK, so that error was:

error[E0277]: the trait bound `RefineFlatIndexImpl<BI>: index::FromInnerPtr` is not satisfied
   --> src/index/refine_flat.rs:225:20
    |
225 | impl<BI: TryClone> TryClone for RefineFlatIndexImpl<BI> {}
    |                    ^^^^^^^^ the trait `index::FromInnerPtr` is not implemented for `RefineFlatIndexImpl<BI>`
    |
note: required by a bound in `index::TryClone`
   --> src/index/mod.rs:339:21
    |
339 | pub trait TryClone: FromInnerPtr {
    |                     ^^^^^^^^^^^^ required by this bound in `index::TryClone`
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
    |
[22](https://github.com/Enet4/faiss-rs/actions/runs/3280362393/jobs/5401039258#step:6:23)5 | impl<BI: TryClone> TryClone for RefineFlatIndexImpl<BI> where RefineFlatIndexImpl<BI>: index::FromInnerPtr {}
    |                                                         ++++++++++++++++++++++++++++++++++++++++++++++++++

The error message already suggests a way to fix the problem, but the way I see it, the TryClone trait is overly restrictive right now due to its default implementation of try_clone. So we can either do what the error suggests or move the default implementation onto those that actually depend on it. The steps would be:

1. Create a helper function try_clone_from_inner_ptr with the default implementation in TryClone::try_clone.
2. Remove default implementation body of method TryClone::try_clone.
3. Remove FromInnerPtr as a supertrait of TryClone
4. In each TryClone implementation with a missing try_clone, add the implementation to make them call try_clone_from_inner_ptr.

Adding a type parameter might make the error go away, but it's not what we want.

[Enet4]

Suggested change

	impl<IndexImpl> FromInnerPtr for RefineFlatIndexImpl<IndexImpl> {
	impl FromInnerPtr for RefineFlatIndexImpl<IndexImpl> {

[Enet4]

I updated the suggested changes above.

[ava57r]

I checked in local PC

error[E0277]: the trait bound `PreTransformIndexImpl<I>: index::FromInnerPtr` is not satisfied
   --> src/index/pretransform.rs:221:19
    |
221 | impl<I: TryClone> TryClone for PreTransformIndexImpl<I> {}
    |                   ^^^^^^^^ the trait `index::FromInnerPtr` is not implemented for `PreTransformIndexImpl<I>`
    |
note: required by a bound in `index::TryClone`
   --> src/index/mod.rs:339:21
    |
339 | pub trait TryClone: FromInnerPtr {
    |                     ^^^^^^^^^^^^ required by this bound in `index::TryClone`
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
    |
221 | impl<I: TryClone> TryClone for PreTransformIndexImpl<I> where PreTransformIndexImpl<I>: index::FromInnerPtr {}
    |                                                         +++++++++++++++++++++++++++++++++++++++++++++++++++

error[E0277]: the trait bound `RefineFlatIndexImpl<BI>: index::FromInnerPtr` is not satisfied
   --> src/index/refine_flat.rs:225:20
    |
225 | impl<BI: TryClone> TryClone for RefineFlatIndexImpl<BI> {}
    |                    ^^^^^^^^ the trait `index::FromInnerPtr` is not implemented for `RefineFlatIndexImpl<BI>`
    |
note: required by a bound in `index::TryClone`
   --> src/index/mod.rs:339:21
    |
339 | pub trait TryClone: FromInnerPtr {
    |                     ^^^^^^^^^^^^ required by this bound in `index::TryClone`
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
    |
225 | impl<BI: TryClone> TryClone for RefineFlatIndexImpl<BI> where RefineFlatIndexImpl<BI>: index::FromInnerPtr {}
    |                                                         ++++++++++++++++++++++++++++++++++++++++++++++++++

For more information about this error, try `rustc --explain E0277`.
error: could not compile `faiss` due to 2 previous errors

[ava57r]

I think trait TryClone needs to change

C++ faiss it is function of Index https://github.com/facebookresearch/faiss/blob/main/faiss/clone_index.h

[Enet4]

Yes, we need to change the TryClone trait so that the trait itself does not depend on FromInnerPtr (and only the implementations do). Following the instructions in my other comment, it should be a smooth change.

[Enet4]

All right, it is good to enter now! Thanks! 👍