Using fastai for Segmentation, receiving a CUDA device-side assertion error

fastai
41

Hello Everyone,

I am also facing the same issue. I have tried the code on both CPU and GPU using colab, but no luck.
Link to notebook file using CPU: http://bit.ly/2I2ZOMX_TGS_CPU
Link to notebook file using GPU: http://bit.ly/2Vq0ROZ_TGS_GPU

In CPU notebook, I am getting the following error:

Target 255 is out of bounds
Target 255 is out of bounds1257×427 55.7 KB

However, I have set div = True in open_mask and have also set num_workers = 0

In GPU notebook I am getting the following error:

CUDA error: device-side assert triggered
CUDA error: device-side assert triggered1288×382 52.7 KB

I have taken the custom metric of IOU.
Fastai version: 1.0.60

Kindly have a look and suggest me how to fix the issue.

43

Hi, @skhandelwal121 in your second screenshot, the error happens when computing loss. It may be the reason that you have 255 in labels, you should also pass the ‘ignore_index=255’ parameter to the loss function.

44

Please, do you have a practical example of how you worked with:

SegmentationItemList._label_cls.open

I’m having the same problem. I believe that there is some inconsistency in the way the data was constructed. I’m a beginner, I’ve tried all the suggestions here and some others. I’m trying to keep things cool.

The error in my jupyter:

RuntimeError: CUDA error: device-side assert triggered

The error looking at the CPU:

C:/w/b/windows/pytorch/aten/src/THCUNN/ClassNLLCriterion.cu:108: block: [0,0,0], thread: [29,0,0] Assertion t >= 0 && t < n_clas ses failed.

Regarding the mask:

[In] src_size, mask.data
[Out] (array([864, 864]),
tensor([[[163, 132, 132, …, 132, 132, 163],
[132, 90, 90, …, 90, 90, 132],
[132, 90, 90, …, 90, 90, 132],
…,
[132, 90, 90, …, 90, 90, 132],
[132, 90, 90, …, 90, 90, 132],
[163, 132, 132, …, 132, 132, 163]]]

I built my database myself. When I did the manual segmentation I used the PixelAnnotation API. It was built for highway segmentation. Then, its segmentation is predetermined, that is, the colors of the segmentation of the colored mask is still selected in the API. And the corresponding gray mask is then built automatically.

The signature of the segmentation of classes by PixelAnnotation was as

Class Pixel intensity
Background 90
Peca 128
DefeitoGrave 76
DefeitoBrando 177

The mask appears to be coherent. Except for markers 132 (edges) and 163 (extremity). They seem to me to be a kind of signature of the edges and ends. Can anyone tell me if I am correct in thinking like this or if it is a mistake that I need to correct?

About classes:

[In] codes = np.loadtxt(path/‘codes.txt’, dtype=str); codes
[Out] array([‘Background’, ‘Peca’, ‘DefeitoGrave’, ‘DefeitoBrando’], dtype=‘<U13’)

So, if I do:

[In] name2id = {v:k for k,v in enumerate(codes)}
print(name2id)
[Out] {‘Background’: 0, ‘Peca’: 1, ‘DefeitoGrave’: 2, ‘DefeitoBrando’: 3}

The classes represented in the script by ‘codes’ are a total of 4, and are indented from 0 to n-1. So, respect the conditions that some comment. However, classes are indented from 1 to 3.

So, what intrigues me. My classes are signed from 0 to 3 but on the mask the same signature is represented by 90, 128, 76, 177. Shouldn’t they be the same? If so, any suggestions or material on how to correct it?

Could this problem be related to the image size? Of course not!?
Is the mask represented by a single channel image? Correct, right?

Environmental information:
Windows 10
pytorch 1.6.0
cuda 10.2
fastai 1.0.61
GeForce GTX 1050 Ti