Compile mnn under linux

mnn is mainly divided into 4 libraries that need to be compiled

(1) Inference part compilation

(2) Compilation of training part

(3) Convert partial compilation

(4) Quantized partial compilation

Compilation requires cmake, gcc, lib and protobuf

Generally the first three libraries are installed, so only protobuf is installed here

git clone https://github.com/google/protobuf.git
cd protobuf
git submodule update --init --recursive
./autogen.sh
./configure
make
make check
sudo make install

If the installation is successful, we can compile mnn 

(1) Inference part compilation

cd mnn
./schema/generate.sh
mkdir build && cd build && cmake .. && make -j8

Note that if the cpu of the machine is not 8 cores, remove -j8, the same below

(2) Compilation of training part

The same is done under the build path

cmake .. -DMNN_BUILD_TRAIN=ON
make -j8

(3) Convert partial compilation

cd build
cmake .. -DMNN_BUILD_CONVERTER=true && make -j4

(4) Quantized partial compilation

cmake .. -DMNN_BUILD_QUANTOOLS=on
make

So far, the compilation is successful