specify gpu architecture level

Author: rusty1s

build.sh

@@ -5,4 +5,4 @@ SRC_DIR=torch_scatter/kernel
 BUILD_DIR=torch_scatter/build
 
 mkdir -p $BUILD_DIR
-nvcc -c -o $BUILD_DIR/kernel.so $SRC_DIR/kernel.cu -Xcompiler -fPIC -shared -I$TORCH/lib/include/TH -I$TORCH/lib/include/THC -I$SRC_DIR
+nvcc -c -o $BUILD_DIR/kernel.so $SRC_DIR/kernel.cu -arch=sm_30 -Xcompiler -fPIC -shared -I$TORCH/lib/include/TH -I$TORCH/lib/include/THC -I$SRC_DIR