TypeError: 'str' object is not callable

Goal: instantiate unet_learner() using weights.

weights is a str that I bring in from a user-defined .yaml file; hence eval().

file_path and training are classes that hold parameters.

Code:

import numpy as np
from fastai.vision.all import *


def train(dls, file_path, training):
    labels = np.loadtxt(file_path.labels, dtype=str)
    weights = torch.tensor(eval(training.weights))

    print('#################')
    print(weights)
    print(type(weights))
    print('#################')

    learner = unet_learner(dls, training.architecture,loss_func=CrossEntropyLossFlat(
        axis=1,
        weight=weights)
    )

    return learner.load(file_path.weights)

Placing torch.tensor() around weights again in the parameter line doesn't help. Same error.

Traceback:

(venv) me@ubuntu-pcs:~/PycharmProjects/project$ python pdl1_lung_train/main.py 
/home/me/miniconda3/envs/venv/lib/python3.7/site-packages/torch/cuda/__init__.py:52: UserWarning: CUDA initialization: Found no NVIDIA driver on your system. Please check that you have an NVIDIA GPU and installed a driver from http://www.nvidia.com/Download/index.aspx (Triggered internally at  /opt/conda/conda-bld/pytorch_1607370156314/work/c10/cuda/CUDAFunctions.cpp:100.)
  return torch._C._cuda_getDeviceCount() > 0
#################
tensor([0.4000, 0.9000])
<class 'torch.Tensor'>
#################
Traceback (most recent call last):
  File "pdl1_lung_train/main.py", line 27, in <module>
    main(ROOT)
  File "pdl1_lung_train/main.py", line 19, in main
    learner = train(dls, file_path, training)
  File "/home/me/PycharmProjects/project/pdl1_lung_train/train.py", line 16, in train
    weight=weights))
  File "/home/me/miniconda3/envs/venv/lib/python3.7/site-packages/fastai/vision/learner.py", line 267, in unet_learner
    model = create_unet_model(arch, n_out, img_size, pretrained=pretrained, **kwargs)
  File "/home/me/miniconda3/envs/venv/lib/python3.7/site-packages/fastai/vision/learner.py", line 243, in create_unet_model
    model = arch(pretrained)
TypeError: 'str' object is not callable

Please let me know if I need to add other info. to post.

CodePudding user response：

I might be wrong but I think your training.architecture is a string. But according to unet_learner documentation it has to be callable.