maxima-bugs

 [Maxima-bugs] [ maxima-Bugs-3369856 ] special case assumed to be general in integration From: SourceForge.net - 2011-07-18 05:16:13 Bugs item #3369856, was opened at 2011-07-17 23:16 Message generated for change (Tracker Item Submitted) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3369856&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core - Integration Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Robert Dodier (robert_dodier) Assigned to: Nobody/Anonymous (nobody) Summary: special case assumed to be general in integration Initial Comment: Problem reported by Frazer Williams to the Maxima mailing list 2011-07-15. I have reproduced his email in extenso below. ---------------- begin quoted text ---------------- Maxima 5.23.2 http://maxima.sourceforge.net using Lisp SBCL 1.0.40-1.fc14 (%i1) f(x):=x^(2*n)*exp(-(x/x0)^2); 2 n x 2 (%o1) f(x) := x exp(- (--) ) x0 (%i2) integrate(f(x),x,-inf,inf); Is 2 n + 1 positive, negative, or zero? p; Is 2 n an integer? y; (%o2) 0 The result should be zero only if 2*n is odd. If we declare n to be an integer, the correct result is produced. (%i3) declare(n,integer); (%o3) done (%i4) integrate(f(x),x,-inf,inf); Is 2 n + 1 positive, negative, or zero? p; Is x0 positive or negative? p; 2 n + 1 2 n + 1 (%o4) gamma(-------) x0 2 ----------------- end quoted text ----------------- ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3369856&group_id=4933
 [Maxima-bugs] [ maxima-Bugs-3369856 ] special case assumed to be general in integration From: SourceForge.net - 2011-07-22 18:27:38 Bugs item #3369856, was opened at 2011-07-18 01:16 Message generated for change (Comment added) made by dgildea You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3369856&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core - Integration Group: None >Status: Closed >Resolution: Fixed Priority: 5 Private: No Submitted By: Robert Dodier (robert_dodier) >Assigned to: Dan Gildea (dgildea) Summary: special case assumed to be general in integration Initial Comment: Problem reported by Frazer Williams to the Maxima mailing list 2011-07-15. I have reproduced his email in extenso below. ---------------- begin quoted text ---------------- Maxima 5.23.2 http://maxima.sourceforge.net using Lisp SBCL 1.0.40-1.fc14 (%i1) f(x):=x^(2*n)*exp(-(x/x0)^2); 2 n x 2 (%o1) f(x) := x exp(- (--) ) x0 (%i2) integrate(f(x),x,-inf,inf); Is 2 n + 1 positive, negative, or zero? p; Is 2 n an integer? y; (%o2) 0 The result should be zero only if 2*n is odd. If we declare n to be an integer, the correct result is produced. (%i3) declare(n,integer); (%o3) done (%i4) integrate(f(x),x,-inf,inf); Is 2 n + 1 positive, negative, or zero? p; Is x0 positive or negative? p; 2 n + 1 2 n + 1 (%o4) gamma(-------) x0 2 ----------------- end quoted text ----------------- ---------------------------------------------------------------------- >Comment By: Dan Gildea (dgildea) Date: 2011-07-22 14:27 Message: Fixed in defint.lisp. Look for discontinuities in antiderivative. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3369856&group_id=4933