AssertionError: Torch not compiled with CUDA enabled

Dear all,
I am trying to the Section "Quick start: Test on an image using our trained model".

[2020-06-09 12:28:55,641 INFO test.py line 172 138659] Loaded configuration file config/ade20k-resnet50dilated-ppm_deepsup.yaml
[2020-06-09 12:28:55,642 INFO test.py line 173 138659] Running with config:
DATASET:
imgMaxSize: 1000
imgSizes: (300, 375, 450, 525, 600)
list_train: ./data/training.odgt
list_val: ./data/validation.odgt
num_class: 150
padding_constant: 8
random_flip: True
root_dataset: ./data/
segm_downsampling_rate: 8
DIR: ade20k-resnet50dilated-ppm_deepsup
MODEL:
arch_decoder: ppm_deepsup
arch_encoder: resnet50dilated
fc_dim: 2048
weights_decoder:
weights_encoder:
TEST:
batch_size: 1
checkpoint: epoch_20.pth
result: ./
TRAIN:
batch_size_per_gpu: 2
beta1: 0.9
deep_sup_scale: 0.4
disp_iter: 20
epoch_iters: 5000
fix_bn: False
lr_decoder: 0.02
lr_encoder: 0.02
lr_pow: 0.9
num_epoch: 20
optim: SGD
seed: 304
start_epoch: 0
weight_decay: 0.0001
workers: 16
VAL:
batch_size: 1
checkpoint: epoch_20.pth
visualize: False
Loading weights for net_encoder
Loading weights for net_decoder

samples: 1
Traceback (most recent call last):
File "test.py", line 198, in
main(cfg, args.gpu)
File "test.py", line 125, in main
segmentation_module.cuda()
File "/home/thomas/anaconda3/envs/env37/lib/python3.7/site-packages/torch/nn/modules/module.py", line 307, in cuda
return self._apply(lambda t: t.cuda(device))
File "/home/thomas/anaconda3/envs/env37/lib/python3.7/site-packages/torch/nn/modules/module.py", line 203, in _apply
module._apply(fn)
File "/home/thomas/anaconda3/envs/env37/lib/python3.7/site-packages/torch/nn/modules/module.py", line 203, in _apply
module._apply(fn)
File "/home/thomas/anaconda3/envs/env37/lib/python3.7/site-packages/torch/nn/modules/module.py", line 225, in _apply
param_applied = fn(param)
File "/home/thomas/anaconda3/envs/env37/lib/python3.7/site-packages/torch/nn/modules/module.py", line 307, in
return self._apply(lambda t: t.cuda(device))
File "/home/thomas/anaconda3/envs/env37/lib/python3.7/site-packages/torch/cuda/__init__.py", line 149, in _lazy_init
_check_driver()
File "/home/thomas/anaconda3/envs/env37/lib/python3.7/site-packages/torch/cuda/__init__.py", line 47, in _check_driver
raise AssertionError("Torch not compiled with CUDA enabled")
AssertionError: Torch not compiled with CUDA enabled

And my laptop is Ubuntu 20.04 without GPU. How can I fix this issue?
Many thanks!