Le ven. 31 mai 2024 à 20:25, Waldek Hebisch <de...@fricas.org> a écrit : > > On Fri, May 31, 2024 at 06:52:11PM +0200, Grégory Vanuxem wrote: > > Hello, > > > > First there is a small typo in FSFUN: > > > > dilog: dilog(z) is the dilogaritm; > > A missing 'h'. > > > > But I do not understand what this function computes in FriCAS, usually > > it is a special case of polylogarithm of order 2. > > We have definition in LiouvillianFunctionCategory: > > dilog : % -> % > ++ dilog(x) returns the dilogarithm of x, i.e. > ++ the integral of \spad{log(x) / (1 - x) dx}. > > It is releated to 'polylog(2, x)': > > (13) -> polylog(2, x) > > (13) dilog(- x + 1) > Type: Expression(Integer) > > > > > In SAGE via https://sagecell.sagemath.org/ > > dilog(0.7) => 0.889377624286039 > > (14) -> dilog(0.3) > > (14) 0.8893776242_8603873859_98408 > Type: Complex(Float)
Exactly what I found too after, trying to reproduce an issue with the triple patch from Qian with official FriCAS. > > WolframAlpha also (https://www.wolframalpha.com/input?i=dilog%5B0.7%5D) > > OK. We inherited this definition from original Axiom sources. > And I did literature research and our definition agrees with > what I found in research papers about dilogarithm and > polylogaritms. > > It is tempting to change definition, but given usage in math > litarature and our previous use I kept what we had. My source was Internet here, I can understand your point of view. I will look at the Expressin domain to khow it is handled so. > > >From https://en.wikipedia.org/wiki/Polylogarithm, there is a > > disambiguation note with lix) (logarithmic integral) > > 'li(x)' is logarithmic integral, quite a different thing than > dilogarithm. Some folks use 'Li' as name of polylogarthim, > that could be confusing. > > > and it seems the > > code use it, but I still don't understand this result in FriCAS: > > > > (3) -> dilog(0.7) > > > > (3) 0.3261295100_7547606953_084133 > > Type: > > Complex(Float) > > > > - Greg > > > > -- > > You received this message because you are subscribed to the Google Groups > > "FriCAS - computer algebra system" group. > > To unsubscribe from this group and stop receiving emails from it, send an > > email to fricas-devel+unsubscr...@googlegroups.com. > > To view this discussion on the web visit > > https://groups.google.com/d/msgid/fricas-devel/CAHnU2dYjsQt6%3DEq4Gva7FkfS6Y1e8-VDSV7YEqymeONB8zPqOQ%40mail.gmail.com. > > -- > Waldek Hebisch > > -- > You received this message because you are subscribed to the Google Groups > "FriCAS - computer algebra system" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to fricas-devel+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/fricas-devel/ZloWMwzCmoPxItaT%40fricas.org. -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving emails from it, send an email to fricas-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/fricas-devel/CAHnU2db_UtwddG9BgPq6MFEf%2BhNOqq9WAB%2Bqo_OvtASqwXNTrQ%40mail.gmail.com.