Install GPU Tensorflow

follow the instructions

http://www.nvidia.com/object/gpu-accelerated-applications-tensorflow-installation.html

export CUDA_ROOT=/usr/local/cuda/  
export LIBRARY_PATH=$CUDA_ROOT/lib:$LIBRARY_PATH

export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$CUDA_ROOT/lib:$CUDA_ROOT/extras/CUPTI/lib"

ln -s libcuda.1.dylib libcuda.dylib

http://blog.wenhaolee.com/run-keras-on-mac-os-with-gpu/