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[Maxima-bugs] [ maxima-Bugs-2942553 ] hgfred([-n, n+1], [1], x) not correct
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From: SourceForge.net <no...@so...> - 2010-01-29 22:17:48
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Bugs item #2942553, was opened at 2010-01-29 23:17 Message generated for change (Tracker Item Submitted) made by crategus You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2942553&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: None Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Dieter Kaiser (crategus) Assigned to: Nobody/Anonymous (nobody) Summary: hgfred([-n,n+1],[1],x) not correct Initial Comment: The result of hgfred([-n,1+n],[1],x) is not correct. This is what Maxima gives: (%i1) res:hgfred([-n,n+1],[1],x); Is x positive, negative, or zero? p; Is x-1 positive, negative, or zero? n; (%o1) legendre_p(-n-1,1-2*x) The correct result is legendre_p(n, 1-2*x). For the special values n=1, n=2, n=3, ... Maxima gives the correct results: (%i2) hgfred([-1,1+1],[1],x); (%o2) 1-2*x (%i3) hgfred([-2,2+1],[1],x); (%o3) 6*x^2-6*x+1 (%i4) hgfred([-3,3+1],[1],x); (%o4) -20*x^3+30*x^2-12*x+1 We can not reproduce the correct results, when we insert the special values in the result from above: (%i5) res,n=1; (%o5) 0 (%i6) res,n=2; (%o6) 0 (%i7) res,n=3; (%o7) 0 Furthermore, I think the question for the sign of the argument x is not necessary. The problem is in the algorithm of the routine legf14. Dieter Kaiser ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2942553&group_id=4933 |