From: SourceForge.net <noreply@so...>  20040304 19:20:32

Bugs item #910008, was opened at 20040304 14:06 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=910008&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Combining Taylor series of different orders Initial Comment: taylor(exp(x),x,0,2)  taylor(exp(x),x,0,0) => x + x^2/2 + ... This is wrong. The result should be 0+... (order 0). taylor(exp(x),x,0,2)  taylor(exp(x),x,0,1) => 0 + ... taylor(exp(x),x,0,2) * taylor(exp(x),x,0,5) => 1 + 2*x + 2*x^2 + ... This time, the printed results are correct: the expansion is only as good as the longest of the component expansions. But taylorinfo of the result is [[x,0,2]], that is, taylor thinks that it is 0 + 0*x + 0*x^2 + ... taylor(taylor(exp(x),x,0,2),x,0,5) => 1 + x + x^2/2 + ... This is correct, and the taylorinfo is correctly [[x,0,2]], but shouldn't it give a warning? taylor(x^2,x,0,1)/x politely gives a warning ("0+... assumed to be zero in Taylor"), but the result has taylorinfo [[x,0,2]]. Shouldn't it have taylorinfo [[x,0,1]]? s  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=910008&group_id=4933 
From: SourceForge.net <noreply@so...>  20060409 20:43:46

Bugs item #910008, was opened at 20040304 12:06 Message generated for change (Settings changed) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=910008&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  Taylor Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Combining Taylor series of different orders Initial Comment: taylor(exp(x),x,0,2)  taylor(exp(x),x,0,0) => x + x^2/2 + ... This is wrong. The result should be 0+... (order 0). taylor(exp(x),x,0,2)  taylor(exp(x),x,0,1) => 0 + ... taylor(exp(x),x,0,2) * taylor(exp(x),x,0,5) => 1 + 2*x + 2*x^2 + ... This time, the printed results are correct: the expansion is only as good as the longest of the component expansions. But taylorinfo of the result is [[x,0,2]], that is, taylor thinks that it is 0 + 0*x + 0*x^2 + ... taylor(taylor(exp(x),x,0,2),x,0,5) => 1 + x + x^2/2 + ... This is correct, and the taylorinfo is correctly [[x,0,2]], but shouldn't it give a warning? taylor(x^2,x,0,1)/x politely gives a warning ("0+... assumed to be zero in Taylor"), but the result has taylorinfo [[x,0,2]]. Shouldn't it have taylorinfo [[x,0,1]]? s  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=910008&group_id=4933 