Update src/streamlit_app.py

src/streamlit_app.py

@@ -1,14 +1,38 @@
 import streamlit as st
 import numpy as np
 import matplotlib.pyplot as plt
+import matplotlib
+import os
+import tempfile
 from kinematics_visualizer import Motion1D, Motion2D, KinematicsVisualizer
 
+# Fix matplotlib configuration for HuggingFace Spaces
+try:
+    # Set matplotlib to use a writable temporary directory
+    temp_dir = tempfile.mkdtemp()
+    os.environ['MPLCONFIGDIR'] = temp_dir
+    matplotlib.use('Agg')  # Use non-interactive backend
+except Exception as e:
+    st.warning(f"Matplotlib configuration warning (app will still work): {e}")
+
 def clear_comparison_state():
     """Clear any lingering comparison state"""
-    keys_to_clear = [key for key in st.session_state.keys() if key.startswith('comp_')]
-    for key in keys_to_clear:
-        if key in st.session_state:
-            del st.session_state[key]
+    try:
+        keys_to_clear = [key for key in st.session_state.keys() if key.startswith('comp_')]
+        for key in keys_to_clear:
+            if key in st.session_state:
+                del st.session_state[key]
+    except Exception:
+        pass  # Silently handle any state clearing issues
+
+def clear_plots():
+    """Safely clear all matplotlib plots"""
+    try:
+        plt.clf()
+        plt.close('all')
+        plt.ioff()  # Turn off interactive mode
+    except Exception:
+        pass
 
 # Configure Streamlit page
 st.set_page_config(
@@ -66,26 +90,47 @@ st.markdown("""
 """, unsafe_allow_html=True)
 
 def main():
+    # Clear plots at the start
+    clear_plots()
+    
     st.markdown('<div class="main-header">🚀 Physics Tutorial: Kinematics</div>', unsafe_allow_html=True)
     
+    # Initialize session state for tutorial selection if not exists
+    if 'tutorial_type' not in st.session_state:
+        st.session_state.tutorial_type = "1D Motion"
+    
     # Sidebar for navigation
     st.sidebar.title("📚 Select Tutorial")
     tutorial_type = st.sidebar.radio(
         "Choose a physics concept:",
-        ["1D Motion", "2D Projectile Motion", "Compare Motions"]
+        ["1D Motion", "2D Projectile Motion", "Compare Motions"],
+        index=["1D Motion", "2D Projectile Motion", "Compare Motions"].index(st.session_state.tutorial_type)
     )
     
+    # Detect tutorial change and clear state
+    if tutorial_type != st.session_state.tutorial_type:
+        st.session_state.tutorial_type = tutorial_type
+        clear_comparison_state()
+        clear_plots()
+        # Force a clean rerun
+        st.rerun()
+    
     # Clear comparison state when not on comparison tab
     if tutorial_type != "Compare Motions":
         clear_comparison_state()
-        plt.close('all')  # Close any lingering plots
+        clear_plots()
     
-    if tutorial_type == "1D Motion":
-        show_1d_motion()
-    elif tutorial_type == "2D Projectile Motion":
-        show_2d_motion()
-    elif tutorial_type == "Compare Motions":
-        show_motion_comparison()
+    # Route to appropriate function
+    try:
+        if tutorial_type == "1D Motion":
+            show_1d_motion()
+        elif tutorial_type == "2D Projectile Motion":
+            show_2d_motion()
+        elif tutorial_type == "Compare Motions":
+            show_motion_comparison()
+    except Exception as e:
+        st.error(f"Error loading tutorial: {str(e)}")
+        st.info("Please refresh the page and try again.")
 
 def show_1d_motion():
     st.markdown('<div class="section-header">📏 One-Dimensional Motion</div>', unsafe_allow_html=True)
@@ -486,75 +531,114 @@ def show_motion_comparison():
     st.markdown("**Compare up to 3 different projectile motions side by side**")
     
     # Clear any previous matplotlib figures explicitly
-    plt.clf()
-    plt.close('all')
+    clear_plots()
+    
+    # Use session state to prevent oscillation
+    if 'comparison_initialized' not in st.session_state:
+        st.session_state.comparison_initialized = True
+        st.session_state.comp_speed1 = 20.0
+        st.session_state.comp_angle1 = 30.0
+        st.session_state.comp_height1 = 0.0
+        st.session_state.comp_speed2 = 25.0
+        st.session_state.comp_angle2 = 45.0
+        st.session_state.comp_height2 = 0.0
+        st.session_state.comp_speed3 = 30.0
+        st.session_state.comp_angle3 = 60.0
+        st.session_state.comp_height3 = 5.0
     
     # Create tabs for different trajectories
     tab1, tab2, tab3 = st.tabs(["🚀 Trajectory 1", "🎯 Trajectory 2", "⚽ Trajectory 3"])
     
     trajectories = []
     
-    # Use containers to isolate each tab's content
+    # Tab 1
     with tab1:
         with st.container():
+            st.subheader("Configure Trajectory 1")
             col1, col2 = st.columns(2)
             with col1:
-                speed1 = st.slider("Speed 1 (m/s)", 5.0, 50.0, 20.0, key="comp_speed1")
-                angle1 = st.slider("Angle 1 (°)", 0.0, 90.0, 30.0, key="comp_angle1")
+                speed1 = st.slider("Speed 1 (m/s)", 5.0, 50.0, st.session_state.comp_speed1, key="slider_speed1")
+                angle1 = st.slider("Angle 1 (°)", 0.0, 90.0, st.session_state.comp_angle1, key="slider_angle1")
             with col2:
-                height1 = st.slider("Height 1 (m)", 0.0, 30.0, 0.0, key="comp_height1")
+                height1 = st.slider("Height 1 (m)", 0.0, 30.0, st.session_state.comp_height1, key="slider_height1")
                 
+            # Update session state
+            st.session_state.comp_speed1 = speed1
+            st.session_state.comp_angle1 = angle1
+            st.session_state.comp_height1 = height1
+            
             motion1 = Motion2D(launch_speed=speed1, launch_angle=angle1, launch_height=height1)
             trajectories.append(("Trajectory 1", motion1, 'blue'))
     
+    # Tab 2
     with tab2:
         with st.container():
+            st.subheader("Configure Trajectory 2")
             col1, col2 = st.columns(2)
             with col1:
-                speed2 = st.slider("Speed 2 (m/s)", 5.0, 50.0, 25.0, key="comp_speed2")
-                angle2 = st.slider("Angle 2 (°)", 0.0, 90.0, 45.0, key="comp_angle2")
+                speed2 = st.slider("Speed 2 (m/s)", 5.0, 50.0, st.session_state.comp_speed2, key="slider_speed2")
+                angle2 = st.slider("Angle 2 (°)", 0.0, 90.0, st.session_state.comp_angle2, key="slider_angle2")
             with col2:
-                height2 = st.slider("Height 2 (m)", 0.0, 30.0, 0.0, key="comp_height2")
+                height2 = st.slider("Height 2 (m)", 0.0, 30.0, st.session_state.comp_height2, key="slider_height2")
                 
+            # Update session state
+            st.session_state.comp_speed2 = speed2
+            st.session_state.comp_angle2 = angle2
+            st.session_state.comp_height2 = height2
+            
             motion2 = Motion2D(launch_speed=speed2, launch_angle=angle2, launch_height=height2)
             trajectories.append(("Trajectory 2", motion2, 'red'))
     
+    # Tab 3
     with tab3:
         with st.container():
+            st.subheader("Configure Trajectory 3")
             col1, col2 = st.columns(2)
             with col1:
-                speed3 = st.slider("Speed 3 (m/s)", 5.0, 50.0, 30.0, key="comp_speed3")
-                angle3 = st.slider("Angle 3 (°)", 0.0, 90.0, 60.0, key="comp_angle3")
+                speed3 = st.slider("Speed 3 (m/s)", 5.0, 50.0, st.session_state.comp_speed3, key="slider_speed3")
+                angle3 = st.slider("Angle 3 (°)", 0.0, 90.0, st.session_state.comp_angle3, key="slider_angle3")
             with col2:
-                height3 = st.slider("Height 3 (m)", 0.0, 30.0, 5.0, key="comp_height3")
+                height3 = st.slider("Height 3 (m)", 0.0, 30.0, st.session_state.comp_height3, key="slider_height3")
                 
+            # Update session state
+            st.session_state.comp_speed3 = speed3
+            st.session_state.comp_angle3 = angle3
+            st.session_state.comp_height3 = height3
+            
             motion3 = Motion2D(launch_speed=speed3, launch_angle=angle3, launch_height=height3)
             trajectories.append(("Trajectory 3", motion3, 'green'))
     
-    # Create comparison plot in its own container
-    with st.container():
+    # Create comparison plot in a separate container
+    st.markdown("---")
+    st.markdown("### 📈 Trajectory Comparison Plot")
+    
+    plot_container = st.container()
+    with plot_container:
         try:
-            # Ensure we have a clean figure
-            plt.close('all')
+            # Create figure with explicit cleanup
             fig, ax = plt.subplots(figsize=(12, 8))
             
             max_range = 0
+            valid_trajectories = 0
+            
             for name, motion, color in trajectories:
                 try:
                     data = motion.trajectory_data(motion.calculate_flight_time())
-                    if len(data['x']) > 0:  # Check data exists
+                    if len(data['x']) > 0:
                         ax.plot(data['x'], data['y'], linewidth=3, label=name, color=color)
                         
                         # Mark launch and landing points
                         ax.plot(motion.launch_x, motion.launch_height, 'o', markersize=8, color=color, alpha=0.7)
-                        ax.plot(data['x'][-1], data['y'][-1], 's', markersize=8, color=color, alpha=0.7)
-                        max_range = max(max_range, data['x'][-1] if data['x'][-1] > 0 else 0)
+                        if len(data['x']) > 0:
+                            ax.plot(data['x'][-1], data['y'][-1], 's', markersize=8, color=color, alpha=0.7)
+                            max_range = max(max_range, data['x'][-1] if data['x'][-1] > 0 else 0)
+                        valid_trajectories += 1
                 except Exception as e:
-                    st.error(f"Error plotting {name}: {str(e)}")
+                    st.warning(f"Could not plot {name}: {str(e)}")
                     continue
             
             # Only proceed if we have valid data
-            if max_range > 0:
+            if valid_trajectories > 0 and max_range > 0:
                 ax.set_xlabel('Horizontal Position (m)', fontsize=12)
                 ax.set_ylabel('Vertical Position (m)', fontsize=12)
                 ax.set_title('Trajectory Comparison', fontsize=16, fontweight='bold')
@@ -563,21 +647,27 @@ def show_motion_comparison():
                 ax.set_ylim(bottom=0)
                 ax.set_xlim(0, max_range * 1.1)
                 
-                # Display plot
-                st.pyplot(fig, clear_figure=True)  # Important: clear_figure=True
+                # Display plot with explicit cleanup
+                st.pyplot(fig, clear_figure=True)
             else:
                 st.warning("No valid trajectory data to display")
                 
         except Exception as e:
             st.error(f"Error creating comparison plot: {str(e)}")
         finally:
-            plt.close(fig)  # Ensure figure is always closed
-            plt.close('all')
+            # Always clean up
+            try:
+                plt.close(fig)
+                plt.close('all')
+            except:
+                pass
     
-    # Comparison table in its own container
-    with st.container():
-        st.markdown("### 📋 Trajectory Comparison Table")
-        
+    # Comparison table
+    st.markdown("---")
+    st.markdown("### 📋 Trajectory Comparison Table")
+    
+    table_container = st.container()
+    with table_container:
         try:
             comparison_data = []
             for name, motion, _ in trajectories:
@@ -593,7 +683,7 @@ def show_motion_comparison():
                         "Max Height (m)": f"{info['max_height']:.1f}"
                     })
                 except Exception as e:
-                    st.error(f"Error getting info for {name}: {str(e)}")
+                    st.warning(f"Could not get data for {name}: {str(e)}")
                     continue
             
             if comparison_data: