# Pytorch multiple GPU count error: UserWarning: CUDA initialization: Unexpected error from cudaGetDeviceCount()

**URL:** <https://discuss.pytorch.org/t/pytorch-multiple-gpu-count-error-userwarning-cuda-initialization-unexpected-error-from-cudagetdevicecount/180627>\
**Category:** distributed\
**Created:** [May 24, 2023, 4:18pm UTC](https://discuss.pytorch.org/t/pytorch-multiple-gpu-count-error-userwarning-cuda-initialization-unexpected-error-from-cudagetdevicecount/180627 "2023-05-24T16:18:26Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Ali\_Waqas](https://discuss.pytorch.org/user_avatar/discuss.pytorch.org/ali_waqas/32/45853_2.png) [@Ali\_Waqas](https://discuss.pytorch.org/u/Ali_Waqas)\
**Post date:** [May 24, 2023, 4:18pm UTC](https://discuss.pytorch.org/t/pytorch-multiple-gpu-count-error-userwarning-cuda-initialization-unexpected-error-from-cudagetdevicecount/180627/1 "2023-05-24T16:18:26Z")

</div>

The following code produce error when using nvidia docker on wsl or wsl.

```py
import torch
torch.cuda.is_available() # False
torch.cuda.device_count() # Error

```

```py
import torch
import os
os.environ["CUDA_VISIBLE_DEVICES"] = "0,1,2" 
torch.cuda.is_available() # False
torch.cuda.device_count() # Error

```

However, it can be resolved by using the code below.

```py
import torch
import os
os.environ["CUDA_VISIBLE_DEVICES"] = "0"   
torch.cuda.is_available() # True
torch.cuda.device_count() # 1

```

Here is the nvidia-smi output. Currently GPU-0 is running a task.

```auto
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 520.61.03 Driver Version: 522.06 CUDA Version: 11.8 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
| | | MIG M. |
|===============================+======================+======================|
| 0 NVIDIA RTX A6000 On | 00000000:01:00.0 On | Off |
| 46% 77C P2 209W / 300W | 32485MiB / 49140MiB | 11% Default |
| | | N/A |
+-------------------------------+----------------------+----------------------+
| 1 NVIDIA RTX A6000 On | 00000000:21:00.0 Off | Off |
| 30% 32C P8 13W / 300W | 0MiB / 49140MiB | 0% Default |
| | | N/A |
+-------------------------------+----------------------+----------------------+
| 2 NVIDIA RTX A6000 On | 00000000:4B:00.0 Off | Off |
| 30% 28C P8 10W / 300W | 0MiB / 49140MiB | 0% Default |
| | | N/A |
+-------------------------------+----------------------+----------------------+
| 3 NVIDIA RTX A6000 On | 00000000:4C:00.0 Off | Off |
| 30% 34C P8 9W / 300W | 36MiB / 49140MiB | 0% Default |
| | | N/A |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes: |
| GPU GI CI PID Type Process name GPU Memory |
| ID ID Usage |
|=============================================================================|
| 0 N/A N/A 34 C /python3.7 N/A |
| 1 N/A N/A 34 C /python3.7 N/A |
| 2 N/A N/A 34 C /python3.7 N/A |
| 3 N/A N/A 34 C /python3.7 N/A |
+-----------------------------------------------------------------------------+

```

As a result i have been able to use only 1 GPU at a time. Any help will be appreciated. thanks.

---

<div class="post-metadata">

**Author:** ![eqy](https://discuss.pytorch.org/user_avatar/discuss.pytorch.org/eqy/32/46233_2.png) [@eqy](https://discuss.pytorch.org/u/eqy)\
**Post date:** [May 24, 2023, 4:45pm UTC](https://discuss.pytorch.org/t/pytorch-multiple-gpu-count-error-userwarning-cuda-initialization-unexpected-error-from-cudagetdevicecount/180627/2 "2023-05-24T16:45:05Z")

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Changing the `CUDA_VISIBLE_DEVICES` environment variable after importing PyTorch seems suspicious e.g., [Os.environ [“CUDA\_VISIBLE\_DEVICES”] not functioning - PyTorch Forums](https://discuss.pytorch.org/t/os-environ-cuda-visible-devices-not-functioning/105545/2)

Could you check if setting it before running your script helps?

---

<div class="post-metadata">

**Author:** ![Ali\_Waqas](https://discuss.pytorch.org/user_avatar/discuss.pytorch.org/ali_waqas/32/45853_2.png) [@Ali\_Waqas](https://discuss.pytorch.org/u/Ali_Waqas)\
**Post date:** [May 24, 2023, 8:32pm UTC](https://discuss.pytorch.org/t/pytorch-multiple-gpu-count-error-userwarning-cuda-initialization-unexpected-error-from-cudagetdevicecount/180627/3 "2023-05-24T20:32:12Z")

</div>

Thanks. i also had to check the `pytorch.version.cuda` which was 10.2. I then reinstalled the pytorch and it worked.

The import of torch should be after after `os.environ["CUDA_VISIBLE_DEVICES"] = "0,1,2" `