"Could not find schema for aten::empty.memory_format" in libtorch

Mobile
1

I’m trying to use libtorch to load a PyTorch model file from native code on Android. When I load the file, I get the following exception:

terminating with uncaught exception of type c10::Error: Could not find schema for aten::empty.memory_format ()
Exception raised from findSchemaOrThrow at /Users/steve/work/torch/pytorch/aten/src/ATen/core/dispatch/Dispatcher.cpp:131 (most recent call first):

I had previously encountered this same problem on iOS, and fixed it by specifying the “-all_load” flag to the linker.

Based on what I saw on iOS, my guess is that there is some static initializer for the tensor code that is getting stripped out and is not getting called. However, what I thought was the equivalent for clang on Android (“-force_load”) causes some additional link errors that I am struggling to fix.

Is there another way to force that initialization? Where in the libtorch code is this schema usually getting registered?

2

Make sure you’re building the libraries using version 21 of the NDK, and then use something like this in the target_link_libraries section of your CMakeLists.txt file:

    -Wl,--gc-sections
    -Wl,--whole-archive
    ${TORCH_LIB_DIR}/libtorch.a
    ${TORCH_LIB_DIR}/libtorch_cpu.a
    -Wl,--no-whole-archive
    ${TORCH_LIB_DIR}/libc10.a
    ${TORCH_LIB_DIR}/libnnpack.a
    ${TORCH_LIB_DIR}/libXNNPACK.a
    ${TORCH_LIB_DIR}/libpytorch_qnnpack.a
    ${TORCH_LIB_DIR}/libpthreadpool.a
    ${TORCH_LIB_DIR}/libeigen_blas.a
    ${TORCH_LIB_DIR}/libcpuinfo.a
    ${TORCH_LIB_DIR}/libclog.a
    ${TORCH_LIB_DIR}/libVulkanWrapper.a