From: SourceForge.net <no...@so...> - 2006-07-31 04:23:52
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Bugs item #1047432, was opened at 2004-10-14 17:01 Message generated for change (Comment added) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1047432&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 - Simplification Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) >Summary: erf(-m) not simplified to -erf(m) when m known to be negativ Initial Comment: assume(m<0)$ integrate((y-m)*%e^-y^2,y,m,inf); gives a result containing erf(-m), which should have simplified to -erf(m). Workaround is easy: just do expand(<<result>>,0,0) to force resimplification. ---------------------------------------------------------------------- >Comment By: Robert Dodier (robert_dodier) Date: 2006-07-30 22:23 Message: Logged In: YES user_id=501686 Observed in 5.9.3cvs. expand(%,0,0) does not cause simplification of erf(-m) to -erf(m). Aside from this problem with the integral: erf(-m) => erf(-m) (not simplified). Dunno if it's relevant, but: featurep(erf, oddfun) => false . HOWEVER with no assumptions about mm, note that erf(-mm) => - erf(mm) . ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1047432&group_id=4933 |