How to use heatmaps in predicting where the classifier is focusing on i need some help ,here is the code.how can i go about it?

username: jim_gitonga
cooked: <pre><code class="lang-auto">```this is my code how can i include the heat_maps

# Define your transforms for the training and validation sets
# Data augmentation and normalization for training
# Just normalization for validation
data_transforms = {
    'train': transforms.Compose([
        transforms.RandomRotation(30),
        transforms.RandomResizedCrop(224),
        transforms.RandomHorizontalFlip(),
        transforms.ToTensor(),
        transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])
    ]),
    'test': transforms.Compose([
        transforms.Resize(256),
        transforms.CenterCrop(224),
        transforms.ToTensor(),
        transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])
    ]),
}

# Load the datasets with ImageFolder

data_dir = 'clasii'
image_datasets = {x: datasets.ImageFolder(os.path.join(data_dir, x),
                                          data_transforms[x])
                  for x in ['train', 'test']}

# Using the image datasets and the transforms, define the dataloaders
dataloaders = {x: torch.utils.data.DataLoader(image_datasets[x], batch_size=4,
                                             shuffle=True, num_workers=0)
              for x in ['train', 'test']}

dataset_sizes = {x: len(image_datasets[x]) for x in ['train', 'test']}


class_names= image_datasets['train'].classes



# Write a function that loads a checkpoint and rebuilds the model

def load_checkpoint(filepath):
    checkpoint = torch.load(filepath)
    model = models.resnet152()
    
    # our input_size matches the in_features of pretrained model
    input_size = 2048
    output_size = 2
    
    classifier = nn.Sequential(OrderedDict([
                          ('fc1', nn.Linear(2048, 1024)),
                          ('relu', nn.ReLU()),
                          #('dropout1', nn.Dropout(p=0.2)),
                          ('fc2', nn.Linear(1024, 2)),
                          ('output', nn.LogSoftmax(dim=1))
                          ]))


    # Replacing the pretrained model classifier with our classifier
    model.fc = classifier
    
    
    model.load_state_dict(checkpoint['state_dict'])
    
    return model, checkpoint['class_to_idx']

# Get index to class mapping
loaded_model, class_to_idx = load_checkpoint('90_checkpoint.pth')
idx_to_class = { v : k for k,v in class_to_idx.items()}




def visualize_model(model, num_images=6):
    was_training = model.training
    model.eval()
    images_so_far = 0
    fig = plt.figure()

    with torch.no_grad():
        for i, (inputs, labels) in enumerate(dataloaders['test']):
            inputs = inputs.to(device)
            labels = labels.to(device)

            outputs = model(inputs)
            _, preds = torch.max(outputs, 1)

            for j in range(inputs.size()[0]):
                images_so_far += 1
                ax = plt.subplot(num_images//2, 2, images_so_far)
                ax.axis('off')
                ax.set_title('predicted: {}'.format(class_names[preds[j]]))
                imshow(inputs.cpu().data[j])

                if images_so_far == num_images:
                    model.train(mode=was_training)
                    return
        model.train(mode=was_training)




def process_image(image):
    ''' Scales, crops, and normalizes a PIL image for a PyTorch model,
        returns an Numpy array
    '''
    
    # Process a PIL image for use in a PyTorch model

    size = 256, 256
    image.thumbnail(size, Image.ANTIALIAS)
    image = image.crop((128 - 112, 128 - 112, 128 + 112, 128 + 112))
    npImage = np.array(image)
    npImage = npImage/255.
        
    imgA = npImage[:,:,0]
    imgB = npImage[:,:,1]
    imgC = npImage[:,:,2]
    
    imgA = (imgA - 0.485)/(0.229) 
    imgB = (imgB - 0.456)/(0.224)
    imgC = (imgC - 0.406)/(0.225)
        
    npImage[:,:,0] = imgA
    npImage[:,:,1] = imgB
    npImage[:,:,2] = imgC
    
    npImage = np.transpose(npImage, (2,0,1))
    
    return npImage



def imshow(image, ax=None, title=None):
    """Imshow for Tensor."""
    if ax is None:
        fig, ax = plt.subplots()
    
    # PyTorch tensors assume the color channel is the first dimension
    # but matplotlib assumes is the third dimension
    image = image.numpy().transpose((0, 2, 0))
    
    # Undo preprocessing
    mean = np.array([0.485, 0.456, 0.406])
    std = np.array([0.229, 0.224, 0.225])
    image = std * image + mean
    
    # Image needs to be clipped between 0 and 1 or it looks like noise when displayed
    image = np.clip(image, 0, 1)
    
    ax.imshow(image)
    
    return ax






def predict(image_path, model, topk=2):
    ''' Predict the class (or classes) of an image using a trained deep learning model.
    '''
    
    # Implement the code to predict the class from an image file
    
    image = torch.FloatTensor([process_image(Image.open(image_path).convert('RGB'))])
    model.eval()
    output = model.forward(Variable(image))
    probabilities = torch.exp(output).data.numpy()[0]
    

    top_idx = np.argsort(probabilities)[-topk:][::-1] 
    top_class = [idx_to_class[x] for x in top_idx]
    top_probability = probabilities[top_idx]

    return top_probability, top_class







# Display an image along with the top  classes
def view_classify(img, probabilities, classes, mapper):
    ''' Function for viewing an image and it's predicted classes.
    '''
    img_filename = 'Prediction'
    img = Image.open(img)

    fig, (ax1, ax2) = plt.subplots(figsize=(6,10),  ncols=1, nrows=2)
    ct_name = img_filename
    
    ax1.set_title(ct_name)
    ax1.imshow(img)
    ax1.axis('off')
    
    y_pos = np.arange(len(probabilities))
    ax2.barh(y_pos, probabilities, color='green')
    ax2.set_yticks(y_pos)
    ax2.set_yticklabels(x for x in classes)
    ax2.invert_yaxis()
    plt.show()

</code></pre>
<pre><code class="lang-auto"></code></pre>

username: ptrblck
cooked: <p><a href="https://captum.ai/">Captum</a> might give you a good toolset for model interpretability.</p>

username: Eta_C
cooked: <p>Before Captum, I use <a href="https://github.com/utkuozbulak/pytorch-cnn-visualizations" rel="nofollow noopener">pytorch-cnn-visualizations</a>.<img src="https://discuss.pytorch.org/images/emoji/apple/laughing.png?v=9" title=":laughing:" class="emoji" alt=":laughing:"></p>

username: Pracheta_Sahoo
cooked: <p>How did you use custom image for pytorch cnn visualization? I am getting this error:</p>
<blockquote>
<p>Blockquote<br>
Traceback (most recent call last):<br>
File “scorecam.py”, line 98, in <br>
save_class_activation_images(original_image, cam, file_name_to_export)<br>
File “/home/pracheta/COVID19/pytorch-cnn-visualizations-master/src/misc_functions.py”, line 65, in save_class_activation_images<br>
heatmap, heatmap_on_image = apply_colormap_on_image(org_img, activation_map, ‘hsv’)<br>
File “/home/pracheta/COVID19/pytorch-cnn-visualizations-master/src/misc_functions.py”, line 97, in apply_colormap_on_image<br>
heatmap_on_image = Image.alpha_composite(heatmap_on_image, heatmap)<br>
File “/home/pracheta/.local/lib/python3.6/site-packages/PIL/Image.py”, line 2916, in alpha_composite<br>
return im1._new(core.alpha_composite(im1.im, im2.im))<br>
ValueError: images do not match</p>
</blockquote>
<blockquote>
<p>Blockquote</p>
</blockquote>

username: Pracheta_Sahoo
cooked: <p><a class="mention" href="/u/ptrblck">@ptrblck</a> Captum produces out of memory error.</p>

username: ptrblck
cooked: <p>How much memory does your device have and what batch size and model are you using?</p>