Strange issue when using HybridBlock in a symbolic program

I defined a custom operation as a HybridBlock and added it to a symbolic codebase. However, when I try to load the model, I get the following error:

MXNetError: Failed loading Op _mul4 of type elemwise_mul: [05:31:13] src/core/ Check failed: op != nullptr Operator elemwise_mul is not registered

Stack trace returned 10 entries:
[bt] (0) /usr/local/lib/python3.5/dist-packages/mxnet/ [0x7f48d2640679]
[bt] (1) /usr/local/lib/python3.5/dist-packages/mxnet/ [0x7f48d266f0b4]
[bt] (2) /usr/local/lib/python3.5/dist-packages/mxnet/ [0x7f48d2673d30]
[bt] (3) /usr/local/lib/python3.5/dist-packages/mxnet/ [0x7f48d266dec6]
[bt] (4) /usr/local/lib/python3.5/dist-packages/mxnet/ [0x7f48d0885a1f]
[bt] (5) /usr/local/lib/python3.5/dist-packages/mxnet/ [0x7f48d2643f78]
[bt] (6) /usr/local/lib/python3.5/dist-packages/mxnet/ [0x7f48d087fead]
[bt] (7) /usr/local/lib/python3.5/dist-packages/mxnet/ [0x7f48d0885a1f]
[bt] (8) /usr/local/lib/python3.5/dist-packages/mxnet/ [0x7f48d2643f78]
[bt] (9) /usr/local/lib/python3.5/dist-packages/mxnet/ [0x7f48d06facae]

Not sure if it’s a bug or it’s the way I implemented the entire thing

Based on CUDA: Unspecified launch failure , my guess is that I didn’t do something too wrong?

Can you post a short code snippet?

Code Snippet is here (Example of using a Gluon HybridBlock in a Symbol Program)

Looks like upgrading to master solves this issue. My guess is elementwise_mul wasn’t registered till recently?

Yes, that’s the root cause.