fastai ulmfit model trained on cuda machin for cpu - gpu

Question

I have an export.pkl model which has been trained on a cuda machine. I want to use it on a macbook:
from fastai.text import load_learner
from utils import get_corpus
learner = load_learner('./models')
corpus = get_corpus()
res = [ str(learner.predict(c)[0]) for c in corpus ]
I get the following error:
...
File "/Users/gautiergilabert/Envs/cc/lib/python3.7/site-packages/torch/nn/parallel/data_parallel.py", line 146, in forward
"them on device: {}".format(self.src_device_obj, t.device))
RuntimeError: module must have its parameters and buffers on device cuda:0 (device_ids[0]) but found one of them on device: cpu
I have two questions:
I found the raise in my export.pkl:
for t in chain(self.module.parameters(), self.module.buffers()):
if t.device != self.src_device_obj:
raise RuntimeError("module must have its parameters and buffers "
"on device {} (device_ids[0]) but found one of "
"them on device: {}".format(self.src_device_obj, t.device))
It is said about the module in the docstring: module to be parallelized. I don't really understand what it is. My macbook ?
Apart my macbook, I would like to run the model on a cpu
Is there a way to make this export.pkl model works on a cpu ?
Is there a way to make another export.pkl on cuda and make it available on a cpu ?
Thanks

Answer 1

One way is to load the learner by specifying the model with empty dataset and loading the model weights afterwards. For resnet image classifier something like this should work:
from fastai.vision import *
# path where the model is saved under path/models/model-name
path = "model_path"
tfms = get_transforms()
data = ImageDataBunch.single_from_classes(".", classes=["class1", "class2"], ds_tfms=tfms)
learner = cnn_learner(data, models.resnet34, metrics=accuracy)
# loads model from model_path/models/model_name.pth
learner.load("model_name")
image = open_image("test.jpg")
pred_class, pred_idx, outputs = learner.predict(image)