Terminate called after throwing an instance of 'c10::Error' what(): isTensor() for LSTM

[ Variable[CPUType]{12,64} ]
terminate called after throwing an instance of ‘c10::Error’
what(): isTensor() ASSERT FAILED at /export/users/long/gits/Pytorch/libtorch-1.0.1/libtorch/include/ATen/core/ivalue.h:205, please report a bug to PyTorch. (toTensor at /export/users/ong/gits/Pytorch/libtorch-1.0.1/libtorch/include/ATen/core/ivalue.h:205)
frame #0: std::function<std::string ()>::operator()() const + 0x11 (0x7fe9e2979441 in /export/users/long/gits/Pytorch/libtorch-1.0.1/libtorch/lib/libc10.so)
frame #1: c10::Error::Error(c10::SourceLocation, std::string const&) + 0x2a (0x7fe9e2978d7a in /export/users/long/gits/Pytorch/libtorch-1.0.1/libtorch/lib/libc10.so)
frame #2: c10::IValue::toTensor() && + 0xa6 (0x4489de in ./dcgan)
frame #3: main + 0x526 (0x4455a0 in ./dcgan)
frame #4: __libc_start_main + 0xf5 (0x7fe9e1508c05 in /usr/lib64/libc.so.6)
frame #5: ./dcgan() [0x443f9c]

Python input
model = torch.load("./model.12.1L.pt", map_location=lambda storage, loc: storage)
hidden = model.init_hidden(args.batch_size)
examples = torch.ones(12, 64).type(torch.LongTensor)
hidden=(torch.zeros(1, 64, 200), torch.zeros(1, 64, 200))
output, hidden = model(examples.to(“cpu”), hidden)

C++ input
torch::Tensor indata1 = torch::ones({12,64}, torch::kLong);
torch::Tensor h0 = torch::from_blob(std::vector(1* 64 * 200, 0.0).data(), {1, 64, 200});
torch::Tensor c0 = torch::from_blob(std::vector(1* 64 * 200, 0.0).data(), {1, 64, 200});
torch::jit::IValue tuple = torch::ivalue::Tuple::create({h0, c0});
at::Tensor output = module->forward({indata1, tuple}).toTensor();

Trouble:
Python input code can output right results, when I transfer to libtorch the problem occurs. anyone kowns how to solve ? Thanks.

@ptrblck hi,could you help me?

Comparing

output, hidden = model(examples.to(“cpu”), hidden)

and

at::Tensor output = module->forward({indata1, tuple}).toTensor();

you would not expect the .toTensor() on the output to succeed, but you probably have a tuple that you need to unpack. This is why isTensor fails.

Best regards

Thomas

P.S.: While you might have preferred ptrblck to answer, it’s generally preferred to not tag people to not discourage anyone who wants to contribute from chiming in.

@tom
Hi,Thomas. Thanks for your time. I‘ve fixed the problems with following your proposal.