Getting non-GUI backend warning when trying to display matplotlib plots in Jupyter notebook

Backend
1

I’m working on a data visualization project in Jupyter notebook and keep running into this annoying warning. Every time I try to show my plots, I get an error saying matplotlib is using a non-GUI backend.

import matplotlib.pyplot as plt
%matplotlib inline

def plot_model_performance(train_data, train_labels, test_data, test_labels):
    """ Creates performance charts for different model configurations """
    
    print("Generating performance charts for various depth settings...")
    
    # Set up the plot area
    figure = plt.figure(figsize=(12, 9))
    
    # Different sample sizes for training
    sample_counts = np.rint(np.linspace(1, len(train_data), 45)).astype(int)
    training_errors = np.zeros(len(sample_counts))
    validation_errors = np.zeros(len(sample_counts))
    
    # Test different depth values
    for idx, tree_depth in enumerate([2, 4, 7, 12]):
        
        for j, sample_size in enumerate(sample_counts):
            
            # Create decision tree with specific depth
            tree_model = DecisionTreeRegressor(max_depth=tree_depth)
            
            # Train on subset of data
            tree_model.fit(train_data[:sample_size], train_labels[:sample_size])
            
            # Calculate training performance
            training_errors[j] = calculate_error(train_labels[:sample_size], 
                                                tree_model.predict(train_data[:sample_size]))
            
            # Calculate validation performance
            validation_errors[j] = calculate_error(test_labels, 
                                                  tree_model.predict(test_data))
        
        # Create subplot for current depth
        subplot = figure.add_subplot(2, 2, idx+1)
        
        subplot.plot(sample_counts, validation_errors, lw=2, label='Validation Error')
        subplot.plot(sample_counts, training_errors, lw=2, label='Training Error')
        subplot.legend()
        subplot.set_title('Tree Depth = %s'%(tree_depth))
        subplot.set_xlabel('Training Sample Count')
        subplot.set_ylabel('Error Rate')
        subplot.set_xlim([0, len(train_data)])
    
    # Final styling
    figure.suptitle('Model Performance Analysis', fontsize=16, y=1.02)
    figure.tight_layout()
    figure.show()

When I execute the plot_model_performance() function, I keep getting this warning message:

UserWarning: matplotlib is currently using a non-GUI backend, so cannot show the figure

The plots don’t display properly and I’m not sure how to fix this backend issue. Has anyone else encountered this problem?

2

Had this issue too! Use plt.show() instead of figure.show(). If that doesn’t work, restart your jupyter kernel and run %matplotlib inline in a new cell. Matplotlib gets weird sometimes.

3

This isn’t a code problem - it’s your environment setup. I’ve hit this tons of times with cloud Jupyter or headless servers. Try %matplotlib notebook instead of %matplotlib inline before plotting. That usually fixes backend conflicts. Also make sure your Jupyter has the right GUI libraries. If you’re using conda, run conda install matplotlib to reinstall with backend support. The warning just means your system’s missing the display components matplotlib wants - super common in containers or remote setups.

4

Hmm, interesting. Are you running this in docker or on a remote server? That backend warning usually pops up when there’s no display. What’s ur setup? Also curious - why figure.show() instead of plt.show()? Was that on purpose?