RNN backward function in evaluation error

[choshin84]

trying to run sample code but getting below error.
appreciate your help

my environment is
Ubuntu 16.04.6 LTS
Pytorch 1.2.0
GPU Titan-V
Cuda version 10.1

Traceback (most recent call last):
File "train_text.py", line 357, in
main(args)
File "train_text.py", line 253, in main
val_nll = eval(val_data, model, meta_optimizer)
File "train_text.py", line 327, in eval
var_params_svi = meta_optimizer.forward([mean_svi, logvar_svi], sents)
File "/home/ubuntu/Program/sa-vae/optim_n2n.py", line 43, in forward
return self.forward_mom(input, y, verbose)
File "/home/ubuntu/Program/sa-vae/optim_n2n.py", line 90, in forward_mom
all_grads_k = torch.autograd.grad(loss, all_input_params, retain_graph = True)
File "/home/ubuntu/.pyenv/versions/3.6.8/lib/python3.6/site-packages/torch/autograd/init.py", line 149, in grad
inputs, allow_unused)
RuntimeError: cudnn RNN backward can only be called in training mode

[HOLMEScdk]

Hi do you solve this?