From: SourceForge.net <no...@so...> - 2003-04-15 03:28:36
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Bugs item #721575, was opened at 2003-04-14 23:45 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=721575&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: 2/sqrt(2) doesn't simplify Initial Comment: 2/sqrt(2) doesn't simplify. Similarly for 2/2^(2/3). On the other hand, x/sqrt(x) => sqrt(x). And of course sqrt(2) simplifies to itself -- it doesn't become 2/sqrt(2)!! I believe the original examples should simplify to sqrt(2) and 2^(1/3). Note that 2^(4/3) => 2*2^(1/3) (the current behavior) is probably CORRECT, in order to make things like 10^(10/3) intelligible. Or is there something I'm missing? Maxima 5.9.0 gcl 2.5.0 mingw32 Windows 2000 Athlon ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=721575&group_id=4933 |
From: SourceForge.net <no...@so...> - 2003-04-17 18:44:10
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Bugs item #721575, was opened at 2003-04-14 22:45 Message generated for change (Comment added) made by willisb You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=721575&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: 2/sqrt(2) doesn't simplify Initial Comment: 2/sqrt(2) doesn't simplify. Similarly for 2/2^(2/3). On the other hand, x/sqrt(x) => sqrt(x). And of course sqrt(2) simplifies to itself -- it doesn't become 2/sqrt(2)!! I believe the original examples should simplify to sqrt(2) and 2^(1/3). Note that 2^(4/3) => 2*2^(1/3) (the current behavior) is probably CORRECT, in order to make things like 10^(10/3) intelligible. Or is there something I'm missing? Maxima 5.9.0 gcl 2.5.0 mingw32 Windows 2000 Athlon ---------------------------------------------------------------------- Comment By: Barton Willis (willisb) Date: 2003-04-17 13:44 Message: Logged In: YES user_id=570592 Try ratsimp with algebraic : true (C1) z : 2/sqrt(2); (D1) 2/SQRT(2) (C2) ratsimp(z); (D2) 2/SQRT(2) (C3) ratsimp(z),algebraic; (D3) SQRT(2) (C4) z : 2/2^(2/3); (D4) 2/2^(2/3) (C5) ratsimp(z); (D5) 2/2^(2/3) (C6) ratsimp(z),algebraic; (D6) 2^(1/3) (C7) ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=721575&group_id=4933 |
From: SourceForge.net <no...@so...> - 2003-04-17 18:53:23
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Bugs item #721575, was opened at 2003-04-14 23:45 Message generated for change (Comment added) made by macrakis You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=721575&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: 2/sqrt(2) doesn't simplify Initial Comment: 2/sqrt(2) doesn't simplify. Similarly for 2/2^(2/3). On the other hand, x/sqrt(x) => sqrt(x). And of course sqrt(2) simplifies to itself -- it doesn't become 2/sqrt(2)!! I believe the original examples should simplify to sqrt(2) and 2^(1/3). Note that 2^(4/3) => 2*2^(1/3) (the current behavior) is probably CORRECT, in order to make things like 10^(10/3) intelligible. Or is there something I'm missing? Maxima 5.9.0 gcl 2.5.0 mingw32 Windows 2000 Athlon ---------------------------------------------------------------------- >Comment By: Stavros Macrakis (macrakis) Date: 2003-04-17 14:53 Message: Logged In: YES user_id=588346 Yes, of course there are ways within Maxima to perform this simplification. But it should be the default in the general simplifer. The logic already appears to be in the general simplifier, but there is a bug in this particular case. If the general simplifier's philosophy were to leave such things untouched, why does it simplify x/sqrt(x) and the like? ---------------------------------------------------------------------- Comment By: Barton Willis (willisb) Date: 2003-04-17 14:44 Message: Logged In: YES user_id=570592 Try ratsimp with algebraic : true (C1) z : 2/sqrt(2); (D1) 2/SQRT(2) (C2) ratsimp(z); (D2) 2/SQRT(2) (C3) ratsimp(z),algebraic; (D3) SQRT(2) (C4) z : 2/2^(2/3); (D4) 2/2^(2/3) (C5) ratsimp(z); (D5) 2/2^(2/3) (C6) ratsimp(z),algebraic; (D6) 2^(1/3) (C7) ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=721575&group_id=4933 |
From: SourceForge.net <no...@so...> - 2003-10-09 03:21:11
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Bugs item #721575, was opened at 2003-04-14 23:45 Message generated for change (Comment added) made by macrakis You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=721575&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: 2/sqrt(2) doesn't simplify Initial Comment: 2/sqrt(2) doesn't simplify. Similarly for 2/2^(2/3). On the other hand, x/sqrt(x) => sqrt(x). And of course sqrt(2) simplifies to itself -- it doesn't become 2/sqrt(2)!! I believe the original examples should simplify to sqrt(2) and 2^(1/3). Note that 2^(4/3) => 2*2^(1/3) (the current behavior) is probably CORRECT, in order to make things like 10^(10/3) intelligible. Or is there something I'm missing? Maxima 5.9.0 gcl 2.5.0 mingw32 Windows 2000 Athlon ---------------------------------------------------------------------- >Comment By: Stavros Macrakis (macrakis) Date: 2003-10-08 23:21 Message: Logged In: YES user_id=588346 More examples. Right-hand side is after ratsimp/algebraic. I believe the general simplifier should be giving those forms. 1/(2*2^(2/3)) 2^(1/3)/4 1/2^(2/3) 2^(1/3)/2 1/(2*SQRT(2)) SQRT(2)/4 1/SQRT(2) SQRT(2)/2 1/(2*2^(1/3)) 2^(2/3)/4 1/2^(1/3) 2^(2/3)/2 Things get worse with non-numeric contents. In the following, each group of expressions denotes the same thing, but none simplifies to the others. I have put *** next to those forms which are the results of ratsimp/algebraic. Note that in several cases, there is more than one equivalent ratsimp'ed form.... 1/(a*b)^(5/2) 1/(a^2*b^2*SQRT(a*b)) *** SQRT(a*b)/(a^3*b^3) *** 1/(a*b)^(3/2) 1/(a*b*SQRT(a*b)) *** SQRT(a*b)/(a^2*b^2) *** 1/(a*b)^(7/6) 1/(a^(2/3)*b^(2/3)*SQRT(a*b)) *** SQRT(a*b)/(a^(5/3)*b^(5/3)) *** (a*b)^(5/6)/(a^2*b^2) *** 1/(a*b)^(5/6) *** 1/(a^(1/3)*b^(1/3)*SQRT(a*b)) *** (a*b)^(1/6)/(a*b) *** SQRT(a*b)/(a^(4/3)*b^(4/3)) *** 1/SQRT(a*b) *** SQRT(a*b)/(a*b) *** a^(1/3)*b^(1/3)/SQRT(a*b) *** 1/(a*b)^(1/6) *** SQRT(a*b)/(a^(2/3)*b^(2/3)) *** (a*b)^(5/6)/(a*b) *** Now it is true that these expressions are in fact not all equivalent as to principal value, but I will leave that exercise for later. Many of them are, and they are not being canonicalized. ---------------------------------------------------------------------- Comment By: Stavros Macrakis (macrakis) Date: 2003-04-17 14:53 Message: Logged In: YES user_id=588346 Yes, of course there are ways within Maxima to perform this simplification. But it should be the default in the general simplifer. The logic already appears to be in the general simplifier, but there is a bug in this particular case. If the general simplifier's philosophy were to leave such things untouched, why does it simplify x/sqrt(x) and the like? ---------------------------------------------------------------------- Comment By: Barton Willis (willisb) Date: 2003-04-17 14:44 Message: Logged In: YES user_id=570592 Try ratsimp with algebraic : true (C1) z : 2/sqrt(2); (D1) 2/SQRT(2) (C2) ratsimp(z); (D2) 2/SQRT(2) (C3) ratsimp(z),algebraic; (D3) SQRT(2) (C4) z : 2/2^(2/3); (D4) 2/2^(2/3) (C5) ratsimp(z); (D5) 2/2^(2/3) (C6) ratsimp(z),algebraic; (D6) 2^(1/3) (C7) ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=721575&group_id=4933 |
From: SourceForge.net <no...@so...> - 2006-07-06 06:01:21
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Bugs item #721575, was opened at 2003-04-14 21:45 Message generated for change (Settings changed) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=721575&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 Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: 2/sqrt(2) doesn't simplify Initial Comment: 2/sqrt(2) doesn't simplify. Similarly for 2/2^(2/3). On the other hand, x/sqrt(x) => sqrt(x). And of course sqrt(2) simplifies to itself -- it doesn't become 2/sqrt(2)!! I believe the original examples should simplify to sqrt(2) and 2^(1/3). Note that 2^(4/3) => 2*2^(1/3) (the current behavior) is probably CORRECT, in order to make things like 10^(10/3) intelligible. Or is there something I'm missing? Maxima 5.9.0 gcl 2.5.0 mingw32 Windows 2000 Athlon ---------------------------------------------------------------------- Comment By: Stavros Macrakis (macrakis) Date: 2003-10-08 21:21 Message: Logged In: YES user_id=588346 More examples. Right-hand side is after ratsimp/algebraic. I believe the general simplifier should be giving those forms. 1/(2*2^(2/3)) 2^(1/3)/4 1/2^(2/3) 2^(1/3)/2 1/(2*SQRT(2)) SQRT(2)/4 1/SQRT(2) SQRT(2)/2 1/(2*2^(1/3)) 2^(2/3)/4 1/2^(1/3) 2^(2/3)/2 Things get worse with non-numeric contents. In the following, each group of expressions denotes the same thing, but none simplifies to the others. I have put *** next to those forms which are the results of ratsimp/algebraic. Note that in several cases, there is more than one equivalent ratsimp'ed form.... 1/(a*b)^(5/2) 1/(a^2*b^2*SQRT(a*b)) *** SQRT(a*b)/(a^3*b^3) *** 1/(a*b)^(3/2) 1/(a*b*SQRT(a*b)) *** SQRT(a*b)/(a^2*b^2) *** 1/(a*b)^(7/6) 1/(a^(2/3)*b^(2/3)*SQRT(a*b)) *** SQRT(a*b)/(a^(5/3)*b^(5/3)) *** (a*b)^(5/6)/(a^2*b^2) *** 1/(a*b)^(5/6) *** 1/(a^(1/3)*b^(1/3)*SQRT(a*b)) *** (a*b)^(1/6)/(a*b) *** SQRT(a*b)/(a^(4/3)*b^(4/3)) *** 1/SQRT(a*b) *** SQRT(a*b)/(a*b) *** a^(1/3)*b^(1/3)/SQRT(a*b) *** 1/(a*b)^(1/6) *** SQRT(a*b)/(a^(2/3)*b^(2/3)) *** (a*b)^(5/6)/(a*b) *** Now it is true that these expressions are in fact not all equivalent as to principal value, but I will leave that exercise for later. Many of them are, and they are not being canonicalized. ---------------------------------------------------------------------- Comment By: Stavros Macrakis (macrakis) Date: 2003-04-17 12:53 Message: Logged In: YES user_id=588346 Yes, of course there are ways within Maxima to perform this simplification. But it should be the default in the general simplifer. The logic already appears to be in the general simplifier, but there is a bug in this particular case. If the general simplifier's philosophy were to leave such things untouched, why does it simplify x/sqrt(x) and the like? ---------------------------------------------------------------------- Comment By: Barton Willis (willisb) Date: 2003-04-17 12:44 Message: Logged In: YES user_id=570592 Try ratsimp with algebraic : true (C1) z : 2/sqrt(2); (D1) 2/SQRT(2) (C2) ratsimp(z); (D2) 2/SQRT(2) (C3) ratsimp(z),algebraic; (D3) SQRT(2) (C4) z : 2/2^(2/3); (D4) 2/2^(2/3) (C5) ratsimp(z); (D5) 2/2^(2/3) (C6) ratsimp(z),algebraic; (D6) 2^(1/3) (C7) ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=721575&group_id=4933 |