Update app.py

app.py

@@ -77,7 +77,7 @@ def display_read_write_graph(G):
     st.pyplot(plt)
 
 # Function to display Simple Graphs for Basic: Simple graph
-def display_simple_graph(G, pos=None):
+def display_simple_graph(G, pos=None, directed=False):
     options = {
         "font_size": 36,
         "node_size": 3000,
@@ -86,9 +86,11 @@ def display_simple_graph(G, pos=None):
         "linewidths": 5,
         "width": 5,
     }
-    
-    # Draw the network
-    nx.draw_networkx(G, pos, **options)
+
+    if directed:
+        nx.draw_networkx(G, pos, **options, arrows=True)  # For directed graph with arrows
+    else:
+        nx.draw_networkx(G, pos, **options)
 
     # Set margins for the axes so that nodes aren't clipped
     ax = plt.gca()
@@ -143,19 +145,21 @@ elif sidebar_option == "Basic: Simple graph":
     st.title("Basic: Simple graph")
     option = st.radio("Choose a graph type:", ("Default Example", "Create your own"))
 
-    # Default example: simple undirected graph
+    # Default example: directed graph with custom positions
     if option == "Default Example":
-        G = nx.Graph()
-        G.add_edge(1, 2)
-        G.add_edge(1, 3)
-        G.add_edge(1, 5)
-        G.add_edge(2, 3)
-        G.add_edge(3, 4)
-        G.add_edge(4, 5)
-
-        # explicitly set positions for visualization
-        pos = {1: (0, 0), 2: (-1, 0.3), 3: (2, 0.17), 4: (4, 0.255), 5: (5, 0.03)}
-        display_simple_graph(G, pos)
+        G = nx.DiGraph([(0, 3), (1, 3), (2, 4), (3, 5), (3, 6), (4, 6), (5, 6)])
+
+        # Group nodes by column
+        left_nodes = [0, 1, 2]
+        middle_nodes = [3, 4]
+        right_nodes = [5, 6]
+
+        # Set the position according to column (x-coordinates)
+        pos = {n: (0, i) for i, n in enumerate(left_nodes)}
+        pos.update({n: (1, i + 0.5) for i, n in enumerate(middle_nodes)})
+        pos.update({n: (2, i + 0.5) for i, n in enumerate(right_nodes)})
+
+        display_simple_graph(G, pos, directed=True)
 
     # Create your own graph
     elif option == "Create your own":
@@ -175,9 +179,9 @@ elif sidebar_option == "Basic: Simple graph":
 
         # Button to generate the graph
         if st.button("Generate"):
-            G_custom = nx.Graph()
+            G_custom = nx.DiGraph()  # Directed graph
             G_custom.add_edges_from(edges)
             
             # Set a basic layout (spring layout as default)
             pos = nx.spring_layout(G_custom, seed=42)
-            display_simple_graph(G_custom, pos)
+            display_simple_graph(G_custom, pos, directed=True)