Error while applying image augmentation transformations to data in FastAI

问题

I am trying to replicate this kaggle notebook https://www.kaggle.com/tanlikesmath/diabetic-retinopathy-with-resnet50-oversampling on Google Colab. The code was working fine till yesterday but today it is throwing a runtime error. Below is the problematic code:

tfms = get_transforms(do_flip=True,flip_vert=True,max_rotate=360,max_warp=0,max_zoom=1.1,max_lighting=0.1,p_lighting=0.5)
src = (ImageList.from_df(df=df,path=data_path,cols='path') #get dataset from dataset //ImageItemList threw errors so changed to ImageList 
        .split_by_idx(range(len(train_df)-1,len(df))) #Splitting the dataset
        .label_from_df(cols='level') #obtain labels from the level column
      )
data= (src.transform(tfms,size=sz) #Data augmentation
        .databunch(bs=bs,num_workers=0) #DataBunch
        .normalize(imagenet_stats) #Normalize
       )

I get the following error:

---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
/usr/local/lib/python3.6/dist-packages/fastai/data_block.py in _check_kwargs(ds, tfms, **kwargs)
    593         x = ds[0]
--> 594         try: x.apply_tfms(tfms, **kwargs)
    595         except Exception as e:

8 frames
/usr/local/lib/python3.6/dist-packages/fastai/vision/image.py in apply_tfms(self, tfms, do_resolve, xtra, size, resize_method, mult, padding_mode, mode, remove_out)
    122                     x = tfm(x, size=_get_crop_target(size,mult=mult), padding_mode=padding_mode)
--> 123             else: x = tfm(x)
    124         return x.refresh()

/usr/local/lib/python3.6/dist-packages/fastai/vision/image.py in __call__(self, x, *args, **kwargs)
    523         "Randomly execute our tfm on `x`."
--> 524         return self.tfm(x, *args, **{**self.resolved, **kwargs}) if self.do_run else x
    525 

/usr/local/lib/python3.6/dist-packages/fastai/vision/image.py in __call__(self, p, is_random, use_on_y, *args, **kwargs)
    469         "Calc now if `args` passed; else create a transform called prob `p` if `random`."
--> 470         if args: return self.calc(*args, **kwargs)
    471         else: return RandTransform(self, kwargs=kwargs, is_random=is_random, use_on_y=use_on_y, p=p)

/usr/local/lib/python3.6/dist-packages/fastai/vision/image.py in calc(self, x, *args, **kwargs)
    474         "Apply to image `x`, wrapping it if necessary."
--> 475         if self._wrap: return getattr(x, self._wrap)(self.func, *args, **kwargs)
    476         else:          return self.func(x, *args, **kwargs)

/usr/local/lib/python3.6/dist-packages/fastai/vision/image.py in affine(self, func, *args, **kwargs)
    182         m = tensor(func(*args, **kwargs)).to(self.device)
--> 183         self.affine_mat = self.affine_mat @ m
    184         return self

RuntimeError: Expected object of scalar type Float but got scalar type Double for argument #3 'mat2' in call to _th_addmm_out

During handling of the above exception, another exception occurred:

Exception                                 Traceback (most recent call last)
<ipython-input-74-31aae73a70fc> in <module>()
      6       )
      7 print(src)
----> 8 data= (src.transform(tfms,size=sz) #Data augmentation
      9         .databunch(bs=bs,num_workers=0) #DataBunch
     10         .normalize(imagenet_stats) #Normalize

/usr/local/lib/python3.6/dist-packages/fastai/data_block.py in transform(self, tfms, **kwargs)
    503         if not tfms: tfms=(None,None)
    504         assert is_listy(tfms) and len(tfms) == 2, "Please pass a list of two lists of transforms (train and valid)."
--> 505         self.train.transform(tfms[0], **kwargs)
    506         self.valid.transform(tfms[1], **kwargs)
    507         if self.test: self.test.transform(tfms[1], **kwargs)

/usr/local/lib/python3.6/dist-packages/fastai/data_block.py in transform(self, tfms, tfm_y, **kwargs)
    722     def transform(self, tfms:TfmList, tfm_y:bool=None, **kwargs):
    723         "Set the `tfms` and `tfm_y` value to be applied to the inputs and targets."
--> 724         _check_kwargs(self.x, tfms, **kwargs)
    725         if tfm_y is None: tfm_y = self.tfm_y
    726         tfms_y = None if tfms is None else list(filter(lambda t: getattr(t, 'use_on_y', True), listify(tfms)))

/usr/local/lib/python3.6/dist-packages/fastai/data_block.py in _check_kwargs(ds, tfms, **kwargs)
    594         try: x.apply_tfms(tfms, **kwargs)
    595         except Exception as e:
--> 596             raise Exception(f"It's not possible to apply those transforms to your dataset:\n {e}")
    597 
    598 class LabelList(Dataset):

Exception: It's not possible to apply those transforms to your dataset:
 Expected object of scalar type Float but got scalar type Double for argument #3 'mat2' in call to _th_addmm_out

I changed nothing in this code, it is the same as it was yesterday but for some reason it gives me an error today. Kindly Help.

Edit: I found out it is working perfectly fine on my local Jupyter notebook. Still shows error for Colab though

回答1:

It seems that some issues with torch that is used in colab

FastAI Forum Try to install specific version of torch in your colab before run fastAI python code

!pip install "torch==1.4" "torchvision==0.5.0"

来源：https://stackoverflow.com/questions/61503339/error-while-applying-image-augmentation-transformations-to-data-in-fastai