Copy_u:source node?

I read the document and find that the function ‘copy_u’ means copying node attributes from source node. Is there any function to copy node attributes from destination nodes ?
If not , I may reverse the graph and use ‘copy_u’ to replace the method. Is that right?

@Twsschx, currently we only support copy from source node and reduce on destination node. This is because we only support reduce on destination nodes, and it make no sense to copy from destination node then reduce on destination node.

Yes reverse the graph and use copy_u + reduce is a workaround. In the next release we plan to support reduce on source nodes (and copy_v you suggested), please stay tuned.