1# -*- coding: utf-8 -*- 2""" 3********** 4Exceptions 5********** 6 7Base exceptions and errors for NetworkX. 8 9""" 10__author__ = """Aric Hagberg (hagberg@lanl.gov)\nPieter Swart (swart@lanl.gov)\nDan Schult(dschult@colgate.edu)\nLoïc Séguin-C. <loicseguin@gmail.com>""" 11# Copyright (C) 2004-2011 by 12# Aric Hagberg <hagberg@lanl.gov> 13# Dan Schult <dschult@colgate.edu> 14# Pieter Swart <swart@lanl.gov> 15# All rights reserved. 16# BSD license. 17# 18 19# Exception handling 20 21# the root of all Exceptions 22class NetworkXException(Exception): 23 """Base class for exceptions in NetworkX.""" 24 25class NetworkXError(NetworkXException): 26 """Exception for a serious error in NetworkX""" 27 28class NetworkXPointlessConcept(NetworkXException): 29 """Harary, F. and Read, R. "Is the Null Graph a Pointless Concept?" 30In Graphs and Combinatorics Conference, George Washington University. 31New York: Springer-Verlag, 1973. 32""" 33 34class NetworkXAlgorithmError(NetworkXException): 35 """Exception for unexpected termination of algorithms.""" 36 37class NetworkXUnfeasible(NetworkXAlgorithmError): 38 """Exception raised by algorithms trying to solve a problem 39 instance that has no feasible solution.""" 40 41class NetworkXNoPath(NetworkXUnfeasible): 42 """Exception for algorithms that should return a path when running 43 on graphs where such a path does not exist.""" 44 45class NetworkXUnbounded(NetworkXAlgorithmError): 46 """Exception raised by algorithms trying to solve a maximization 47 or a minimization problem instance that is unbounded.""" 48 49class NetworkXNotImplemented(NetworkXException): 50 """Exception raised by algorithms not implemented for a type of graph.""" 51