Update app.py

app.py

@@ -84,29 +84,41 @@ def minimum_spanning_tree_graph():
         num_nodes = st.number_input("Number of nodes", min_value=2, value=5)
         num_edges = st.number_input("Number of edges", min_value=1, value=6)
 
-        # Create random graph with user input
-        G = nx.gnm_random_graph(num_nodes, num_edges)
+        # Create empty graph
+        G = nx.Graph()
 
-        # Add random weights to the edges
-        for u, v in G.edges():
-            G[u][v]["weight"] = st.number_input(f"Weight for edge ({u}, {v})", value=1)
+        # Allow user to input the edges and their weights manually
+        edges = []
+        for i in range(num_edges):
+            source = st.number_input(f"Source node for edge {i+1}", min_value=0, max_value=num_nodes-1, key=f"source_{i}")
+            dest = st.number_input(f"Destination node for edge {i+1}", min_value=0, max_value=num_nodes-1, key=f"dest_{i}")
+            weight = st.number_input(f"Weight for edge ({source}, {dest})", min_value=1, value=1, key=f"weight_{i}")
+            edges.append((source, dest, {"weight": weight}))
 
-        # Find the minimum spanning tree
-        T = nx.minimum_spanning_tree(G)
+        # Add edges to the graph
+        G.add_edges_from(edges)
 
-        # Visualize the graph and the minimum spanning tree
-        pos = nx.spring_layout(G)
-        fig, ax = plt.subplots(figsize=(8, 8))
-        nx.draw_networkx_nodes(G, pos, node_color="lightblue", node_size=500, ax=ax)
-        nx.draw_networkx_edges(G, pos, edge_color="grey", ax=ax)
-        nx.draw_networkx_labels(G, pos, font_size=12, font_family="sans-serif", ax=ax)
-        nx.draw_networkx_edge_labels(
-            G, pos, edge_labels={(u, v): d["weight"] for u, v, d in G.edges(data=True)}, ax=ax
-        )
-        nx.draw_networkx_edges(T, pos, edge_color="green", width=2, ax=ax)
-        ax.set_title("Custom Graph and Minimum Spanning Tree")
-        plt.axis("off")
-        st.pyplot(fig)
+        # Add nodes to the graph (to ensure all nodes are included, even if not explicitly added by the user)
+        G.add_nodes_from(range(num_nodes))
+
+        # Button to generate the graph and calculate MST
+        if st.button("Generate Graph"):
+            # Find the minimum spanning tree
+            T = nx.minimum_spanning_tree(G)
+
+            # Visualize the graph and the minimum spanning tree
+            pos = nx.spring_layout(G)
+            fig, ax = plt.subplots(figsize=(8, 8))
+            nx.draw_networkx_nodes(G, pos, node_color="lightblue", node_size=500, ax=ax)
+            nx.draw_networkx_edges(G, pos, edge_color="grey", ax=ax)
+            nx.draw_networkx_labels(G, pos, font_size=12, font_family="sans-serif", ax=ax)
+            nx.draw_networkx_edge_labels(
+                G, pos, edge_labels={(u, v): d["weight"] for u, v, d in G.edges(data=True)}, ax=ax
+            )
+            nx.draw_networkx_edges(T, pos, edge_color="green", width=2, ax=ax)
+            ax.set_title("Custom Graph and Minimum Spanning Tree")
+            plt.axis("off")
+            st.pyplot(fig)
 
 # Display the corresponding page based on sidebar option
 if sidebar_option == "Graph: Minimum Spanning Tree":