FWIW, after rebuilding Sage with system’s giac :
sage: integrate(e^x/(x^2+1), x, -pi, pi) 1/2*(imag_part(Ei(pi + I))*tan(1/2)^2 - imag_part(Ei(pi - I))*tan(1/2)^2 + 2*real_part(Ei(pi + I))*tan(1/2) + 2*real_part(Ei(pi - I))*tan(1/2) - imag_part(Ei(pi + I)) + imag_part(Ei(pi - I)))/(tan(1/2)^2 + 1) - 1/2*(imag_part(Ei(-pi + I))*tan(1/2)^2 - imag_part(Ei(-pi - I))*tan(1/2)^2 + 2*real_part(Ei(-pi + I))*tan(1/2) + 2*real_part(Ei(-pi - I))*tan(1/2) - imag_part(Ei(-pi + I)) + imag_part(Ei(-pi - I)))/(tan(1/2)^2 + 1) sage: giac.version() "giac 1.7.0, (c) B. Parisse and R. De Graeve, Institut Fourier, Universite de Grenoble I" But now, ptestlong exhibits new bugs <https://groups.google.com/g/sage-release/c/aOpjpfOXgro/m/03WJYuNTFwAJ>. Sigh (again)… HTH, Le dimanche 30 janvier 2022 à 07:25:48 UTC+1, Emmanuel Charpentier a écrit : > To add insult to injury, trying to re-enable system’s giac (make > giac-clean && configure failed. Somehow,./configurefinds no *suitable* > systemgiacversion, and re-builds Sage's giac. It seems that I should also > cleanpari` and consorts and re-re-build… > > Sigh… > > Le vendredi 28 janvier 2022 à 23:10:23 UTC+1, dmo...@deductivepress.ca a > écrit : > >> I confirm the problem so please open a ticket. >> >> I tried 9.5rc4 on MacOS 11.5.2, I tried 9.4 and 9.5rc4 on Ubuntu 20.04 >> (CoCalc), and I tried 9.5rc3 on a 32-bit Debian virtual machine. Maybe >> something would have happened eventually, but none of them gave an answer >> within 20 minutes. The giac version seems to be 1.6.0 in all cases. >> >> On Friday, January 28, 2022 at 1:23:08 PM UTC-7 emanuel.c...@gmail.com >> wrote: >> >>> Can’t reproduce on Sage 9.5.rc1 running in Debian testing. First thing >>> after session start : >>> >>> sage: integrate(e^x/(x^2+1), x, -pi, pi) >>> // Giac share root-directory:/usr/share/giac/ >>> // Giac share root-directory:/usr/share/giac/ >>> Added 0 synonyms >>> 1/2*(imag_part(Ei(pi + I))*tan(1/2)^2 - imag_part(Ei(pi - I))*tan(1/2)^2 + >>> 2*real_part(Ei(pi + I))*tan(1/2) + 2*real_part(Ei(pi - I))*tan(1/2) - >>> imag_part(Ei(pi + I)) + imag_part(Ei(pi - I)))/(tan(1/2)^2 + 1) - >>> 1/2*(imag_part(Ei(-pi + I))*tan(1/2)^2 - imag_part(Ei(-pi - I))*tan(1/2)^2 >>> + 2*real_part(Ei(-pi + I))*tan(1/2) + 2*real_part(Ei(-pi - I))*tan(1/2) - >>> imag_part(Ei(-pi + I)) + imag_part(Ei(-pi - I)))/(tan(1/2)^2 + 1) >>> >>> BTW: >>> >>> sage: integrate(e^x/(x^2+1), x).simplify_full() >>> 1/2*(2*I*cos(1/2)^2 + 2*cos(1/2)*sin(1/2) - I)*Ei(x + I) + >>> 1/2*(-2*I*cos(1/2)^2 + 2*cos(1/2)*sin(1/2) + I)*Ei(x - I) >>> sage: integrate(e^x/(x^2+1), x, algorithm="fricas").simplify_full() >>> 1/2*(-I*Ei(x - I)*e^(2*I) + I*Ei(x + I))*e^(-I) >>> >>> And these expressions are equal : >>> >>> sage: integrate(e^x/(x^2+1), x).trig_reduce().exponentialize().factor() >>> -1/2*I*(Ei(x - I)*e^(2*I) - Ei(x + I))*e^(-I) >>> sage: integrate(e^x/(x^2+1), x, algorithm="fricas") >>> -1/2*I*(Ei(x - I)*e^(2*I) - Ei(x + I))*e^(-I) >>> >>> Mathematica gives the same (mathematical) result (but this can’t be >>> backtranslated to Sage now, for lack of ExpIntegralEi in the >>> translation dictionary) : >>> >>> sage: mathematica.Integrate(e^x/(x^2+1), x) >>> ((-I/2)*(E^(2*I)*ExpIntegralEi[-I + x] - ExpIntegralEi[I + x]))/E^I >>> >>> HTH, >>> >>> Le vendredi 28 janvier 2022 à 11:56:14 UTC+1, Emmanuel Briand a écrit : >>> >>>> Using Sage 9.4 installed with conda on Mac OS X 10.13.6, I observe an >>>> erratic behaviour of "integrate" for a very specific integral. >>>> >>>> The following command runs forever: >>>> >>>> sage: integrate(e^x/(x^2+1), x, -pi, pi) >>>> >>>> (The problem does not show up with another interval of integration, e.g. >>>> 0, pi or -pi, 0 instead of -pi, pi). >>>> >>>> After interrupting, the following message is shown: >>>> >>>> ^CInterrupting Giac... >>>> >>>> integrate(e^x/(x^2 + 1), x, -pi, pi) >>>> >>>> Running a second time the command returns the question, which is ok. >>>> >>>> sage: integrate(e^x/(x^2+1), x, -pi, pi) >>>> integrate(e^x/(x^2 + 1), x, -pi, pi) >>>> >>>> But running a third time (or fourth o more) the command returns a wrong >>>> result: >>>> >>>> sage: integrate(e^x/(x^2+1), x, -pi, pi) >>>> -pi*e^x/(x^2 + 1) - x*e^x/(x^2 + 1) >>>> >>>> Actually, after that, no integral of th same function can be calculated: >>>> >>>> sage: integrate(e^x/(x^2+1), x,0, 1) >>>> -x*e^x/(x^2 + 1) >>>> >>>> Intgrls of other functions are ok. >>>> >>>> >>>> >>>> The problem does not show up when avoiding giac: >>>> >>>> sage: integrate(e^x/(x^2+1), x, -pi, pi, algorithm='maxima') >>>> integrate(e^x/(x^2 + 1), x, -pi, pi) >>>> >>>> Asking for the giac version gives no clue: >>>> >>>> sage: giac.version() >>>> "Done" >>>> >>>> Should I open a ticket for this? >>>> >>>> Emmanuel Briand >>>> >>>> >>>> >>>> -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/0b60ad20-db89-4309-b670-fd0c3ed2ac51n%40googlegroups.com.
