- it is possible to use C++ in Cython - It is also possible to make an efficient implementation in C++ and to make an optional (experimental) package making an interface for Sagemath
Le lundi 16 mars 2020 10:44:52 UTC+1, João Tavares a écrit : > > > A general definition is that the diameter of a non connected undirected > graph is +oo. > > Similarly, the diameter of a non strongly connected directed graph is > +oo. > > We should use these definitions. > I pushed my changes to trac yesterday with the simplifications > resulting from using this definition. > After testing with a couple of graphs it seems to run faster than the > previous algorithm for sparse graphs. > I've implemented it in Cython because it seems to be the preferred > option but perhaps a C/C++ implementation would be even faster. > > Thanks for the reply. > João Tavares > > On Mon, Mar 16, 2020 at 8:18 AM David Coudert <[email protected] > <javascript:>> wrote: > > > > The first step is to somehow draw a map of the different algorithms that > are already available in Sagemath, and the conditions to use them > (directed, undirected, weighted, multi edges, etc.), and the data structure > used. > > Then we can decide how to proceed. > > > > A general definition is that the diameter of a non connected undirected > graph is +oo. > > Similarly, the diameter of a non strongly connected directed graph is > +oo. > > We should use these definitions. > > > > Le dimanche 15 mars 2020 00:59:14 UTC+1, João Tavares a écrit : > >> > >> Thanks for the reply and for the corrections on trac. > >> While trying to fix and issue I found that I was essentially > >> reinventing the wheel and that my problem had been solved elsewhere on > >> the codebase. > >> However when I tried to understand how they had deal with it I found > >> they had not. > >> > >> The article [d2] seems to use a different definition of eccentricity > >> and by extension of diameter where the graph does not need to be > >> connected. > >> Meaning sage.graphs.distances_all_pairs.diameter() would return > >> different values for different algorithms, which as a user I would not > >> expect. > >> How has Sage dealt with these cases in the past? Should I restrict it > >> to the previous definition or maybe have a different function with a > >> different name? > >> > >> > >> > >> On Mon, Mar 9, 2020 at 8:27 PM David Coudert <[email protected]> > wrote: > >> > > >> > Thank you for your interest in this project. > >> > > >> > If you push your code to a ticket, we will certainly help you > improving it. We do our best to help all contributors. > >> > > >> > Sincerely, > >> > David. > >> > > >> > Le lundi 9 mars 2020 20:05:24 UTC+1, João Tavares a écrit : > >> >> > >> >> Hello, > >> >> > >> >> > >> >> I am a third year undergraduate student from IST - Lisbon University > in Applied Mathematics and Computer Science. I am very > >> >> interested in the "Diameter, radius, eccentricities, and distances" > project. In fact I have started implementing [d2]. > >> >> > >> >> I have some knowledge about the trac system, having submited a small > enhancement in the past, however I have a small question regarding it. > >> >> > >> >> Is it acceptable for me to push my current implementation to trac > under the need_work tag and perhaps get some feedback? I have been working > under the assumption the given graph is undirected (temporarily) so my code > is not yet complete. > >> >> > >> >> > >> >> Thanks for the replies in advance. > >> >> > >> >> > >> >> Best regards, > >> >> > >> >> João Tavares > >> >> > >> >> IST - Lisbon University > >> > > >> > -- > >> > You received this message because you are subscribed to the Google > Groups "sage-gsoc" group. > >> > To unsubscribe from this group and stop receiving emails from it, > send an email to [email protected]. > >> > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-gsoc/46f0612e-4736-4a7a-883d-83a53748ee4e%40googlegroups.com. > > > > > > -- > > You received this message because you are subscribed to the Google > Groups "sage-gsoc" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to [email protected] <javascript:>. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-gsoc/ab9ea629-92c0-4be6-9505-b952952ecafd%40googlegroups.com. > > > -- You received this message because you are subscribed to the Google Groups "sage-gsoc" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-gsoc/54c568ee-adbd-4959-a2d1-8bd50dbb22f2%40googlegroups.com.
