Error in torchScript based on Pytorch tutorial

C++
1

I’m new to Pytorch and it C++ API. I followed the this tutorial in order to learn how to load and process a .pt file in C++.

Unfortunately, while the code is built correctly, and loads the pt file without errors, when I try to execute something from the saved module, it raises the following error:


terminate called after throwing an instance of 'std::runtime_error'
  what():  The following operation failed in the TorchScript interpreter.
Traceback of TorchScript, serialized code (most recent call last):
  File "code/__torch__.py", line 11, in forward
    if bool(torch.gt(torch.sum(input), 0)):
      weight = self.weight
      output = torch.mv(weight, input)
               ~~~~~~~~ <--- HERE
    else:
      weight0 = self.weight

Traceback of TorchScript, original code (most recent call last):
  File "torchScript.py", line 10, in forward
    def forward(self, input):
        if input.sum() > 0:
            output = self.weight.mv(input)
                     ~~~~~~~~~~~~~~ <--- HERE
        else:
            output = self.weight + input
RuntimeError: vector + matrix @ vector expected, got 1, 2, 4

Aborted (core dumped)

How can I fix it ?
Thank you in advance

2

Did you just rerun the entire tutorial or did you change the inputs to another structure?

3

@ptrblck thank you for your answer. I followed the tutorial without any change. I converted the torch script via annotation and not via tracing.
My torchscript:

import torch

class MyModule(torch.nn.Module):
    def __init__(self, N, M):
        super(MyModule, self).__init__()
        self.weight = torch.nn.Parameter(torch.rand(N, M))

    def forward(self, input):
        if input.sum() > 0:
            output = self.weight.mv(input)
        else:
            output = self.weight + input
        return output

my_module = MyModule(10,20)
sm = torch.jit.script(my_module)

sm.save("my_module_model.pt")

My cpp code:

#include <torch/script.h> // One-stop header.

#include <iostream>
#include <memory>

int main(int argc, const char* argv[]) {
  if (argc != 2) {
    std::cerr << "usage: example-app <path-to-exported-script-module>\n";
    return -1;
  }


  torch::jit::script::Module module;
  try {
    // Deserialize the ScriptModule from a file using torch::jit::load().
    module = torch::jit::load(argv[1]);
  }
  catch (const c10::Error& e) {
    std::cerr << "error loading the model\n";
    return -1;
  }

  // Create a vector of inputs.
  std::vector<torch::jit::IValue> inputs;
  inputs.push_back(torch::ones({1, 3, 224, 224}));

  // Execute the model and turn its output into a tensor.
  at::Tensor output = module.forward(inputs).toTensor();
  std::cout << output.slice(/*dim=*/1, /*start=*/0, /*end=*/5) << '\n';

  std::cout << "ok\n";
}

My setup:
Pytorch: 1.9.0 (building from source)
Cuda: 10.2
Cudnn: 8.2.2
g++: 8.4
Python 3.6 (Anaconda)

4

Thanks for raising this issue! Could you create an issue on GitHub so that we could track and fix it, please?

5

Yes, of course, I’ ll create the issue as soon as possible.

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