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pythonvariablesrecursionglobal-variables

Call a function inside another function but a variable are declared/instantiated/ initialized/ assigned from another function


Problem

def a(...):
 model = b(...)

I running a(...) but model is not defined.

the b(...) looks like:

def b(...):
 ... 
 model=...
 ...
return model

My question: What is my problem called in python? So I can solve it. Something like global/local, or nested function, recursive, static, calling functions inside function, or declaring/instantiating/ initializing/ assigning from another function?

Below is the same question but with my real code because i had google it, so I maybe need help for my concrete case.

What I run:

start_parameter_searching(lrList, momentumList, wdList )

Function:

def start_parameter_searching(lrList, wdList, momentumList):
for i in lrList:
  for k in momentumList:
    for j in wdListt:
      set_train_validation_function(i, k, j)
      trainFunction()

lrList = [0.001, 0.01, 0.1]
wdList = [0.001, 0.01, 0.1]
momentumList = [0.001, 0.01, 0.1]

Error

NameError                                 Traceback (most recent call last)
<ipython-input-20-1d7a642788ca> in <module>()
----> 1 start_parameter_searching(lrList, momentumList, wdList)

1 frames
<ipython-input-17-cd25561c1705> in trainFunction()
     10   for epoch in range(num_epochs):
     11       # train for one epoch, printing every 10 iterations
---> 12       _, loss = train_one_epoch(model, optimizer, data_loader, device, epoch, print_freq=10)
     13       # update the learning rate
     14       lr_scheduler.step()

NameError: name 'model' is not defined

Problem

I run def set_train_validation_function(i, k, j): in my def start_parameter_searching(lrList, wdList, momentumList):

Inside def set_train_validation_function(i, k, j): I have model = get_instance_segmentation_model(num_classes) and the model is not defined. The get_instance_segmentation_model(num_classes) is probably not being called/declared/instatiated again. The function is also inside another function.

Everything put together in a pseudo code file

def set_train_validation_function(i, k, j):
    device = torch.device('cuda') if torch.cuda.is_available() else torch.device('cpu')

# our dataset has two classes only - background and person
num_classes = 2

# get the model using our helper function
model = get_instance_segmentation_model(num_classes)
# move model to the right device
model.to(device)

# construct an optimizer
params = [p for p in model.parameters() if p.requires_grad]
optimizer = torch.optim.SGD(params, lr=i,
                            momentum=k, weight_decay=j)

# and a learning rate scheduler which decreases the learning rate by
# 10x every 3 epochs
lr_scheduler = torch.optim.lr_scheduler.StepLR(optimizer,
                                            step_size=3,
                                            gamma=0.1)


def start_parameter_searching(lrList, wdList, momentumList):
    for i in lrList:
      for k in momentumList:
        for j in wdListt:
          set_train_validation_function(i, k, j)
          trainFunction()

lrList = [0.001, 0.01, 0.1]
wdList = [0.001, 0.01, 0.1]
momentumList = [0.001, 0.01, 0.1]

#start training
start_parameter_searching(lrList, momentumList, wdList )

and from the problem with model = get_instance_segmentation_model(num_classes)

def get_instance_segmentation_model(num_classes):
# load an instance segmentation model pre-trained on COCO
model = torchvision.models.detection.maskrcnn_resnet50_fpn(pretrained=True)

# get the number of input features for the classifier
in_features = model.roi_heads.box_predictor.cls_score.in_features
# replace the pre-trained head with a new one
model.roi_heads.box_predictor = FastRCNNPredictor(in_features, num_classes)

# now get the number of input features for the mask classifier
in_features_mask = model.roi_heads.mask_predictor.conv5_mask.in_channels
hidden_layer = 256
# and replace the mask predictor with a new one
model.roi_heads.mask_predictor = MaskRCNNPredictor(in_features_mask,
                                                   hidden_layer,
                                                   num_classes)

return model

Solution

  • It sounds like you are not returning model and passing it on.

    Did you mean:

    model = set_train_validation_function(i, k, j)
    trainFunction(model)
    

    This will mean that def set_train_validation_function(...): will need to return model and then you will need def trainFunction(model):