Summary

Hi, it seems, that current version in master is not compilable, the GPU compilation failed with following error:

gpu/impl/PQScanMultiPassNoPrecomputed.cu(27): error: function "faiss::gpu::isSupportedNoPrecomputedSubDimSize" has already been defined

gpu/impl/PQScanMultiPassNoPrecomputed.cu(51): error: class template "faiss::gpu::LoadCodeDistances" has already been defined

gpu/impl/PQScanMultiPassNoPrecomputed.cu(123): error: function template "faiss::gpu::pqScanNoPrecomputedMultiPass" has already been defined

3 errors detected in the compilation of "/tmp/tmpxft_0007f108_00000000-11_PQScanMultiPassNoPrecomputed.compute_75.cpp1.ii".
make: *** [Makefile:45: gpu/impl/PQScanMultiPassNoPrecomputed.o] Error 1
make: *** Waiting for unfinished jobs....

Platform

OS: Arch Linux

$ gcc -v
Using built-in specs.
COLLECT_GCC=/usr/bin/gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/9.3.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-pkgversion='Arch Linux 9.3.0-1' --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --enable-shared --enable-threads=posix --with-system-zlib --with-isl --enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object --enable-linker-build-id --enable-lto --enable-plugin --enable-install-libiberty --with-linker-hash-style=gnu --enable-gnu-indirect-function --enable-multilib --disable-werror --enable-checking=release --enable-default-pie --enable-default-ssp --enable-cet=auto gdc_include_dir=/usr/include/dlang/gdc
Thread model: posix
gcc version 9.3.0 (Arch Linux 9.3.0-1) 

$ nvcc -V
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2019 NVIDIA Corporation
Built on Wed_Oct_23_19:24:38_PDT_2019
Cuda compilation tools, release 10.2, V10.2.89

Faiss version: a17a631

Faiss compilation options: nothing fancy.

Reproduction instructions

Compiling current master on Linux with GPU should be enough. I am also a maintainer of AUR faiss package