# -*- coding: utf-8 -*-
"""
**********
Exceptions
**********
Base exceptions and errors for NetworkX.
"""
__author__ = """Aric Hagberg (hagberg@lanl.gov)\nPieter Swart (swart@lanl.gov)\nDan Schult(dschult@colgate.edu)\nLoïc Séguin-C. <loicseguin@gmail.com>"""
# Copyright (C) 2004-2015 by
# Aric Hagberg <hagberg@lanl.gov>
# Dan Schult <dschult@colgate.edu>
# Pieter Swart <swart@lanl.gov>
# All rights reserved.
# BSD license.
#
# Exception handling
# the root of all Exceptions
[docs]class NetworkXException(Exception):
"""Base class for exceptions in NetworkX."""
[docs]class NetworkXError(NetworkXException):
"""Exception for a serious error in NetworkX"""
[docs]class NetworkXPointlessConcept(NetworkXException):
"""Harary, F. and Read, R. "Is the Null Graph a Pointless Concept?"
In Graphs and Combinatorics Conference, George Washington University.
New York: Springer-Verlag, 1973.
"""
[docs]class NetworkXAlgorithmError(NetworkXException):
"""Exception for unexpected termination of algorithms."""
[docs]class NetworkXUnfeasible(NetworkXAlgorithmError):
"""Exception raised by algorithms trying to solve a problem
instance that has no feasible solution."""
[docs]class NetworkXNoPath(NetworkXUnfeasible):
"""Exception for algorithms that should return a path when running
on graphs where such a path does not exist."""
class NetworkXNoCycle(NetworkXUnfeasible):
"""Exception for algorithms that should return a cycle when running
on graphs where such a cycle does not exist."""
[docs]class NetworkXUnbounded(NetworkXAlgorithmError):
"""Exception raised by algorithms trying to solve a maximization
or a minimization problem instance that is unbounded."""
class NetworkXNotImplemented(NetworkXException):
"""Exception raised by algorithms not implemented for a type of graph."""