Article View: comp.lang.functional
Article #997Reverse diffs [was Re: functional programming formulation of graph algorithms]
From: John W. Baugh Jr.
Date: Wed, 29 May 1991 22:29
Date: Wed, 29 May 1991 22:29
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Thomas M. Breuel writes about "reverse diffs": > I think this is the wrong approach. Using data structures based on > reverse diffs (as in RCS), an update involving side effects: > > val new_graph = (Graph.update_add_edge(graph,from,to); graph) > > is no more efficient (except for possibly a small, constant time > overhead) than a more functional formulation: > > val new_graph = Graph.with_edge(graph,from,to) I've never heard of reverse diffs--could you please give some examples and/or references. Also, can reverse diffs deal effectively with other structured data types (like matrices: constant access & constant update)? John Baugh jwb@cepmax.ncsu.edu
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!zaphod.mps.ohio-state.edu!ncar!gatech!taco!cepmax.ncsu.edu!jwb From: jwb@cepmax.ncsu.edu (John W. Baugh Jr.) Newsgroups: comp.lang.functional Subject: Reverse diffs [was Re: functional programming formulation of graph algorithms] Message-ID: <1991May29.222935.13101@ncsu.edu> Date: 29 May 91 22:29:35 GMT References: <TMB.91May29174602@volterra.ai.mit.edu> <5332@ztivax.UUCP> <REDDY.91May28195125@reddy.cs.uiuc.edu> Sender: news@ncsu.edu (USENET News System) Reply-To: jwb@cepmax.ncsu.edu Organization: North Carolina State University Lines: 19