reducing inference dependencies

[lunixbochs]

• inference depends on a cblas library for SpeechUtils
  It looks like fbgemm can do a gemm on its own (it's even in the name), but wav2letter libraries won't build without another cblas library present, due to the SpeechUtils cblasGemm function

• inference depends on gflags, which isn't mentioned in the wiki

git clone https://github.com/gflags/gflags.git
cd gflags
cmake .
make && make install

[avidov]

• inference depends on a cblas library for SpeechUtils
  It looks like fbgemm can do a gemm on its own (it's even in the name), but wav2letter libraries won't build without another cblas library present, due to the SpeechUtils cblasGemm function

This is a good point. Currently inference reuses libraries/feature/FeatureParams.h which uses cblas, but we should use whatever backend inference is set to use (currently only supports FBGEMM but soon will support others for mobile platforms). I marked it as desired enhancement for now.

inference depends on gflags, which isn't mentioned in the wiki

Inference examples using gflags. CMake searches for it and download it if not found, so the wiki does not ask to install manually.

[lunixbochs]

CMake searches for it and download it if not found, so the wiki does not ask to install manually.

This doesn't seem to happen for me:

-- Could NOT find GFlags (missing: GFLAGS_INCLUDE_DIR GFLAGS_LIBRARY) 
CMake Error at inference/CMakeLists.txt:43 (message):
  GFLAGS not found

When running from wav2letter/build on a Mac

KENLM_ROOT_DIR=~/build/kenlm/build cmake .. -DW2L_BUILD_LIBRARIES_ONLY=ON -DW2L_BUILD_INFERENCE=ON -DW2L_LIBRARIES_USE_CUDA=OFF

[lunixbochs]

as fbgemm is already a dependency, maybe it's simpler to just always use a function from that for featurization instead of playing cblas hot potato?