02_production something wrong with DataBlock.dataloaders

Part 1 (2020)
1

Hi,

I don’t know why but I cannot create the dataloaders from the ‘bears’ DataBlock. When I run the cell:

dls = bears.dataloaders(path)

I get the error:

Could not do one pass in your dataloader, there is something wrong in it

All previous cells run fine, and I have the bears images in place. If I run:

dls = bears.dataloaders(path, verbose=True)

Then I get:

Setting up after_item: Pipeline: Resize -- {'size': (128, 128), 'method': 'crop', 'pad_mode':
'reflection', 'resamples': (2, 0), 'p': 1.0} -> ToTensor
Setting up before_batch: Pipeline: 
Setting up after_batch: Pipeline: IntToFloatTensor -- {'div': 255.0, 'div_mask': 1}
Could not do one pass in your dataloader, there is something wrong in it

I am running the notebooks in paperspace gradient as specified in the documentation of the course.

Does anyone have a hint on what could be wrong or where to look to find the problem?

2

Can we see your bears DataBlock?

3

Yes, it is the code from lesson 2:

bear_types = 'grizzly','black','teddy'
path = Path('bears')

if not path.exists():
    path.mkdir()
    for o in bear_types:
        dest = (path/o)
        dest.mkdir(exist_ok=True)
        results = search_images_bing(key, f'{o} bear')
        download_images(dest, urls=results.attrgot('content_url'))

bears = DataBlock(
    blocks=(ImageBlock, CategoryBlock), 
    get_items=get_image_files, 
    splitter=RandomSplitter(valid_pct=0.1, seed=41),
    get_y=parent_label,
    item_tfms=Resize(128))
4

There is another thread around the error you reported - Error while using tabular in v2. This mentions the need to install the right version of fastcore. Can you try this?

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5

Thanks. I restarted my gradient instance and updated fastai and that fixed the problem.

6

FWIW downgrading fastcore from 1.3.19 to 1.3.17 allowed me to continue.

The adult sample works with 1.2.19, so it could be my data, I need to look into it further.

[Update] Re-ran with fastcore 1.3.19 and works fine, can’t really say what changed, sorry.

1 Like