How to force cv2 to use second GPU in Python for dnn

Python
,
1

I’m trying to get mobilenet detectors working on multiple cameras on my local network, with inference running on two GPUs. I searched around a bit and found out you can select a specific GPU using cv2.cuda.SetDevice(gpuid), but that didn’t work for me in OpenCV 4.5. Is this command deprecated/obsolete?

2

welcome.

please explain “didn’t work”.

1 Like
3

It gave me an error saying the command didn’t exist, that SetDevice wasn’t a method for the cv2.cuda class.

4

Have you compiled OpenCV with CUDA?

I just tried

cv2.cuda.setDevice(0)

with no errors and when I tried device 1 which doesn’t exist I get the below error informing me of that

OpenCV(4.5.0) Error: Gpu API call (invalid device ordinal) in cv::cuda::setDevice, file modules\core\src\cuda_info.cpp, line 73
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
cv2.error: OpenCV(4.5.0) \modules\core\src\cuda_info.cpp:73: error: (-217:Gpu API call) invalid device ordinal in function 'cv::cuda::setDevice'
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5

I just reran the program with cv2.cuda.setDevice(1) instead of cv2.cuda.SetDevice(1), and it ran. I think the guide that I read had the capitalization wrong. Sorry for the dumb mistake. My best guess as to why device 1 didn’t work for you but worked for me is because you might not have a second GPU.

6

Also, I’m new, how do you insert blocks of code like you did?

7

three backticks for a block:

```
generic code here
```

```python
python code here. try other languages too
```

single backticks for inline code

single backticks for `inline` code

or indent by 4 spaces for monospaced text without highlighting. toolbar above text entry box has a button for that.

1 Like
8

Thanks!

cv2.cuda.setDevice(1)