Graph Building Utilities

def graph_from_edges(edge_list, node_prefix='', directed=False):
    """
    Creates graph from edge list.
    
    Parameters:
    - edge_list (Sequence): List of tuples representing edges [(src, dst), ...]
    - node_prefix (str): Prefix to add to node names (default: '')
    - directed (bool): Create directed graph if True, undirected if False
    
    Returns:
    Dot: Graph object with nodes and edges from the edge list
    """

def graph_from_adjacency_matrix(matrix, node_prefix='', directed=False):
    """
    Creates graph from adjacency matrix.
    
    Parameters:
    - matrix (Sequence[Sequence]): Square matrix where matrix[i][j] represents
      connection from node i to node j. Non-zero values create edges.
    - node_prefix (str): Prefix to add to node names (default: '')  
    - directed (bool): Create directed graph if True, undirected if False
    
    Returns:
    Dot: Graph object representing the adjacency relationships
    """

def graph_from_incidence_matrix(matrix, node_prefix='', directed=False):
    """
    Creates graph from incidence matrix.
    
    Parameters:
    - matrix (Sequence[Sequence]): Matrix where rows are nodes and columns are edges.
      Non-zero entries indicate node participation in edges.
    - node_prefix (str): Prefix to add to node names (default: '')
    - directed (bool): Create directed graph if True, undirected if False
    
    Returns:
    Dot: Graph object representing the incidence relationships
    """

def call_graphviz(program, arguments, working_dir, **kwargs):
    """
    Call GraphViz programs directly.
    
    Parameters:
    - program (str): GraphViz program name ('dot', 'neato', etc.)
    - arguments (list[str]): Command line arguments
    - working_dir (str|bytes): Working directory for execution
    - **kwargs: Additional subprocess parameters
    
    Returns:
    tuple[str, str, subprocess.Popen]: (stdout, stderr, process)
    """

def quote_id_if_necessary(s, unquoted_keywords=None):
    """
    Enclose identifier in quotes if needed for DOT syntax.
    
    Parameters:
    - s (str): String to potentially quote
    - unquoted_keywords (Sequence[str], optional): Keywords that don't need quoting
    
    Returns:
    str: Quoted string if necessary, original string otherwise
    """

def quote_attr_if_necessary(s):
    """
    Enclose attribute value in quotes if needed.
    
    Parameters:
    - s (str): Attribute value to potentially quote
    
    Returns:
    str: Quoted string if necessary
    """

import pydot

# Simple edge list
edges = [
    ('A', 'B'),
    ('B', 'C'), 
    ('C', 'D'),
    ('D', 'A')
]

# Create undirected graph
graph = pydot.graph_from_edges(edges, directed=False)
graph.write_png("cycle_graph.png")

# Create directed graph with node prefix
directed_graph = pydot.graph_from_edges(edges, node_prefix="node_", directed=True)
print(directed_graph.to_string())

import pydot

# Define adjacency matrix (4x4 nodes)
# 0 = no connection, 1 = connection exists
adjacency = [
    [0, 1, 0, 1],  # Node 0 connects to nodes 1 and 3
    [1, 0, 1, 0],  # Node 1 connects to nodes 0 and 2  
    [0, 1, 0, 1],  # Node 2 connects to nodes 1 and 3
    [1, 0, 1, 0]   # Node 3 connects to nodes 0 and 2
]

# Create graph from matrix
graph = pydot.graph_from_adjacency_matrix(adjacency, node_prefix="v")
graph.set_layout("neato")  # Good for symmetric graphs
graph.write_png("adjacency_graph.png")

# Weighted adjacency matrix
weighted_adjacency = [
    [0, 5, 0, 3],
    [5, 0, 2, 0],
    [0, 2, 0, 4],
    [3, 0, 4, 0]
]

weighted_graph = pydot.graph_from_adjacency_matrix(weighted_adjacency)
# Edge weights can be accessed through the edges
for edge in weighted_graph.get_edges():
    # Weight information is embedded in the graph structure
    pass

import pydot

# Incidence matrix: rows=nodes, columns=edges
# Entry (i,j) = 1 if node i is incident to edge j
incidence = [
    [1, 1, 0, 0],  # Node 0 incident to edges 0,1
    [1, 0, 1, 0],  # Node 1 incident to edges 0,2
    [0, 1, 1, 1],  # Node 2 incident to edges 1,2,3
    [0, 0, 0, 1]   # Node 3 incident to edge 3
]

graph = pydot.graph_from_incidence_matrix(incidence, node_prefix="n")
graph.write_svg("incidence_graph.svg")

import pydot

# Example: Social network connections
social_network = [
    ('Alice', 'Bob'),
    ('Alice', 'Charlie'),
    ('Bob', 'Diana'),
    ('Charlie', 'Diana'),
    ('Diana', 'Eve'),
    ('Charlie', 'Eve')
]

# Create social network graph
social_graph = pydot.graph_from_edges(social_network, directed=False)

# Style the graph
social_graph.set_bgcolor("lightblue")
social_graph.set_layout("fdp")  # Force-directed layout for social networks

# Style nodes (people)
for node in social_graph.get_nodes():
    node.set_shape("circle")
    node.set_style("filled")
    node.set_fillcolor("lightgreen")

# Style edges (relationships)
for edge in social_graph.get_edges():
    edge.set_color("darkblue")
    edge.set_penwidth("2")

social_graph.write_png("social_network.png")

# If you have NetworkX graphs, you can convert to edge list first
import networkx as nx
import pydot

# Create NetworkX graph
nx_graph = nx.erdos_renyi_graph(10, 0.3)

# Convert to edge list
edge_list = list(nx_graph.edges())

# Create pydot graph
pydot_graph = pydot.graph_from_edges(edge_list, node_prefix="node_")
pydot_graph.write_png("random_graph.png")