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## maxima-bugs

 [Maxima-bugs] [ maxima-Bugs-812968 ] is(equal(...)) says unknown, ratsimp says 0 From: SourceForge.net - 2003-09-26 09:29:04 ```Bugs item #812968, was opened at 2003-09-26 02:29 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=812968&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Joel Ray Holveck (piquan) Assigned to: Nobody/Anonymous (nobody) Summary: is(equal(...)) says unknown, ratsimp says 0 Initial Comment: The way I understood EQUAL, it seems that it's supposed to answer true if ratsimp returns true. But in the following equation, it is clear that this is not happening. Sorry about the mess; this was the simplest reproduction scenario I could find. (C112) is(equal(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)), (x-1)/(2*x*sqrt(2)))); (D112) UNKNOWN (C113) is(equal(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)), (x)/(2*x*sqrt(2))-1/(2*x*sqrt(2)))); (D113) TRUE (C114) ratsimp(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)) - (x-1)/(2*x*sqrt(2))); (D114) 0 (C115) facts(); (D115) [NOT EQUAL(x, 0)] I did consider that the problem may be related to the fact that ratsimp simplifies the two sides of the equation differently, so I tried putting them on the same side. In the following, the left side of the equal ratsimp's to 0 (as seen in D114), and yet equal doesn't assert that it's equal to 0. (C130) is(equal(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)) - (x-1)/(2*x*sqrt(2)), 0)); (D130) UNKNOWN I may be missing something obvious here-- I'm just learning Maxima-- but this seems off to me. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=812968&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-812968 ] is(equal(...)) says unknown, ratsimp says 0 From: SourceForge.net - 2003-09-27 17:58:57 ```Bugs item #812968, was opened at 2003-09-26 05:29 Message generated for change (Comment added) made by macrakis You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=812968&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Joel Ray Holveck (piquan) Assigned to: Nobody/Anonymous (nobody) Summary: is(equal(...)) says unknown, ratsimp says 0 Initial Comment: The way I understood EQUAL, it seems that it's supposed to answer true if ratsimp returns true. But in the following equation, it is clear that this is not happening. Sorry about the mess; this was the simplest reproduction scenario I could find. (C112) is(equal(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)), (x-1)/(2*x*sqrt(2)))); (D112) UNKNOWN (C113) is(equal(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)), (x)/(2*x*sqrt(2))-1/(2*x*sqrt(2)))); (D113) TRUE (C114) ratsimp(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)) - (x-1)/(2*x*sqrt(2))); (D114) 0 (C115) facts(); (D115) [NOT EQUAL(x, 0)] I did consider that the problem may be related to the fact that ratsimp simplifies the two sides of the equation differently, so I tried putting them on the same side. In the following, the left side of the equal ratsimp's to 0 (as seen in D114), and yet equal doesn't assert that it's equal to 0. (C130) is(equal(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)) - (x-1)/(2*x*sqrt(2)), 0)); (D130) UNKNOWN I may be missing something obvious here-- I'm just learning Maxima-- but this seems off to me. ---------------------------------------------------------------------- >Comment By: Stavros Macrakis (macrakis) Date: 2003-09-27 13:58 Message: Logged In: YES user_id=588346 You are absolutely right: this is a bug. Worse, is(equal(1/sqrt(2),sqrt(2)/2)) and even is(equal(1/sqrt (2)-sqrt(2)/2,0)) return False! As you say, it should be using ratsimp(1/sqrt(2)-sqrt(2)/2) -- which does correctly return 0. It is also a known problem (bug?) that 1/sqrt(2) and sqrt(2)/2 do not simplify to the same thing, but as you say, even when you put them on the same side, it doesn't work.... 5.9.0 gcl 2.5.0 W2k ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=812968&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-812968 ] is(equal(...)) says unknown, ratsimp says 0 From: SourceForge.net - 2006-03-27 00:44:16 ```Bugs item #812968, was opened at 2003-09-26 03:29 Message generated for change (Comment added) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=812968&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: Joel Ray Holveck (piquan) Assigned to: Nobody/Anonymous (nobody) Summary: is(equal(...)) says unknown, ratsimp says 0 Initial Comment: The way I understood EQUAL, it seems that it's supposed to answer true if ratsimp returns true. But in the following equation, it is clear that this is not happening. Sorry about the mess; this was the simplest reproduction scenario I could find. (C112) is(equal(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)), (x-1)/(2*x*sqrt(2)))); (D112) UNKNOWN (C113) is(equal(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)), (x)/(2*x*sqrt(2))-1/(2*x*sqrt(2)))); (D113) TRUE (C114) ratsimp(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)) - (x-1)/(2*x*sqrt(2))); (D114) 0 (C115) facts(); (D115) [NOT EQUAL(x, 0)] I did consider that the problem may be related to the fact that ratsimp simplifies the two sides of the equation differently, so I tried putting them on the same side. In the following, the left side of the equal ratsimp's to 0 (as seen in D114), and yet equal doesn't assert that it's equal to 0. (C130) is(equal(x/(2*x*sqrt(2)) - 1/(2*x*sqrt(2)) - (x-1)/(2*x*sqrt(2)), 0)); (D130) UNKNOWN I may be missing something obvious here-- I'm just learning Maxima-- but this seems off to me. ---------------------------------------------------------------------- >Comment By: Robert Dodier (robert_dodier) Date: 2006-03-26 17:44 Message: Logged In: YES user_id=501686 Looking at src/compar.lisp, it appears that the compare and sign functions don't call ratsimp, maybe they should. Hard to tell what's going on in compar.lisp. ---------------------------------------------------------------------- Comment By: Stavros Macrakis (macrakis) Date: 2003-09-27 11:58 Message: Logged In: YES user_id=588346 You are absolutely right: this is a bug. Worse, is(equal(1/sqrt(2),sqrt(2)/2)) and even is(equal(1/sqrt (2)-sqrt(2)/2,0)) return False! As you say, it should be using ratsimp(1/sqrt(2)-sqrt(2)/2) -- which does correctly return 0. It is also a known problem (bug?) that 1/sqrt(2) and sqrt(2)/2 do not simplify to the same thing, but as you say, even when you put them on the same side, it doesn't work.... 5.9.0 gcl 2.5.0 W2k ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=812968&group_id=4933 ```