Extract minst.zip to any folder. Run DotnextNN.ConsoleTest:
./DotNextNN.ConsoleTest TrainMNIST -path=[path to MNIST] -epochs=20
You can also run matrix dot product test with
./DotNextNN.ConsoleTest CompareBlasWithLoops
You can install OpenBLAS on MacOs with
brew install openblas
And you will need to set LD_LIBRARY_PATH so that .NET runtime can find the library.
export LD_LIBRARY_PATH=$PATH:/usr/local/opt/openblas/lib