GPU: the [GPU implementation in caffe](https://github.com/rbgirshick/caffe-fast-rcnn/blob/fast-rcnn/src/caffe/layers/roi_pooling_layer.cu) the [GPU implementation in caffe2](https://github.com/caffe2/caffe2/blob/master/caffe2/operators/roi_pool_op.cu) CPU: the [GPU implementation in caffe](https://github.com/rbgirshick/caffe-fast-rcnn/blob/fast-rcnn/src/caffe/layers/roi_pooling_layer.cpp) the [GPU implementation in caffe2](https://github.com/caffe2/caffe2/blob/master/caffe2/operators/roi_pool_op.cc)
