Rebuild for cuda110

[regro-cf-autotick-bot]

This PR has been triggered in an effort to update cuda110.

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[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[h-vetinari]

@teju85

We're not currently building for Ampere here - do you think I should add 80 to the ARCHES here? And would you know what's the minimum cuda version that supports building for Ampere?

https://github.com/conda-forge/faiss-split-feedstock/blob/45baa90f1d0e1525ead09a2cc8fea409518f4040/recipe/build-lib.sh#L8-L21

[teju85]

@h-vetinari yes, you will have to add 80 to the ARCHES list and the minimum cuda version that supports it is 11.0.

I also couldn't help but notice the check used to conditionally add newer arch support. To be portable across multiple cuda versions that we throw at this script, it needs to be updated to:

 if [ `echo "${cuda_compiler_version} >= "10.0" | bc` = "1" ]; then 
     # cuda >= 10.0 supports Turing (sm_75) 
     ARCHES+=(75) 
     LATEST_ARCH=75 
 fi
 if [ `echo "${cuda_compiler_version} >= "11.0" | bc` = "1" ]; then 
     # cuda >= 11.0 supports Ampere (sm_80) 
     ARCHES+=(80) 
     LATEST_ARCH=80 
 fi

[h-vetinari]

Thanks a lot for the quick reply @teju85! You're absolutely right that the script could be improved, it was just hacked together based on the conditions at the time, which allowed things to be handled with a single if.

I committed your suggestion just now, let's see how it goes (my machine didn't have bc for example).

[teju85]

You're welcome.

My bad, I should have mentioned this earlier! Using bc is one way to do this. But if you know of other, more robust ways to express this in shell script, please feel free to use those too.

[h-vetinari]

@jakirkham @isuruf

I'm getting tons of warnings like the following on the cuda11 build:

warning: CUB requires C++14. Please pass -std=c++14 to your compiler.
warning: Thrust requires C++14. Please pass -std=c++14 to your compiler.

Any reason we shouldn't use -std=c++14 for cuda11?

[jakirkham]

Using C++14 should be fine. Though we might be using an even newer version by default like C++17. It can be overridden though.

CUDA 11.0 includes CUB and Thrust. I’m not sure to what extent faiss uses them though. Hopefully that provides some more context.

[h-vetinari]

@jakirkham, thanks!

Default seems to be c++11 though: .../x86_64-conda-linux-gnu-c++ -std=c++11 -DFINTEGER=int ...

[jakirkham]

The features added between C++11 and C+14 is quite small. So bumping should be fine.

Though I must admit the use of C++11 is a bit unexpected

[h-vetinari]

I agree on the first count, no opinion on the second.

I didn't find anything in the cf knowledge base or the compiler tools reference about how to set the standard version though, and GH sucks at searching for "c++" so I couldn't find something in the various repos (e.g. conda-build) where this might be tucked away. Help appreciated. :)

[jakirkham]

My understanding is this is where we set the C++ flags. FWICT it is using C++17. Is it possible C++11 is coming from something else (perhaps in faiss' build scripts)?

[h-vetinari]

@jakirkham The setting was hidden somewhere deep in the autoconf setup of the faiss-sources. I patched it to c++14, because nvcc apparently doesn't suppor c++17 yet.

Warnings are gone now and everything builds correctly, so merging.

[jakirkham]

Ah ok. That makes sense.

Yeah sticking with C++14 sounds like a better choice.

Great! Thanks for working on this 😄