On Friday, October 31, 2014 10:30:52 AM UTC-7, Sergey Kirpichev wrote: > > > On Friday, October 31, 2014 1:49:23 AM UTC+3, Richard Fateman wrote: >> >> If they knew anything about debugging and SymPy, which is not so probable. >> > > The point is - it's ultimately improbable for closed-source program. > > For closed-source commercial programs it is possible to report a bug and have an expert resolve the problem accurately and promptly.
How likely is this?? I think it depends on (a) how important the bug is (b) how important the person reporting the bug is (c) how much money/lives/etc depend on the bug being fixed. for bugs reported in Mathematica, the first line of defense is to have someone who knows almost nothing send you email that you should read the documentation and that it is a feature. This is actually the correct response for many bug reports. My guess is that you were a big commercial customer for Mathematica, you'd get better service. (Could you get worse service?) For bugs in (say) the computer programs that control the power-distribution grid for the country, I'd say that the usefulness of open-source for the end-user is very low. If my electric power at my residence fails, I'm not going to debug the grid. I also doubt that my local electric company (PGE) is going to attempt to prove source code for nuclear reactor safety from EPRI is correct, whether it is open source or not. http://mydocs.epri.com/docs/CorporateDocuments/Newsroom/EPRI_NUC_faq.pdf On a more mundane level, I do not expect my ATM transactions to have bugs in them, but if I found some problem I would not wish for open source so I can fix it. Or probably worse, have some high school student just learning python try to fix the ATM. By the way, computer algebra type work HAS been used for nuclear reactor safety codes in the past, to my knowledge. Support for "symbolic execution" helps improve confidence in correctness of programs. Maybe it is still used. As for bugs, consider the expression (in mathematica syntax) Sum[x^i, {i, 0, n}] which is computed in closed form, but consider specific values, say x=2, n=-4. for which the correct answer is -7/8 even though Sum[2^i,{i.0,-4}] comes out 0. Now try it in other programs. It is often possible to trick systems in essentially identical ways into computing 0^0 as 0 or as 1 or as something undefined. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/dd00a1d9-9aee-4435-9a78-609fc968849c%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
