maxima-bugs

 [Maxima-bugs] [ maxima-Bugs-611129 ] Egregious bug in Solve/Algsys From: - 2002-09-18 14:52:34 ```Bugs item #611129, was opened at 2002-09-18 10:52 You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=611129&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Egregious bug in Solve/Algsys Initial Comment: In a very simple case, Solve/Algsys (a) reports many incorrect solutions and (b) misses all the parameterized solutions. -- Define equations eqs: [a+b+c=0, a*b*c=1] -- These seem pretty simple, don't they? -- Solve 2 equations for 3 unknowns (normal algsys) sols: solve(eqs,[a,b,c]) -- Gives 12 solutions -- Substitute back the solutions subst: map(lambda([sol],subst(sol,eqs)),sols) -- Big mess -- Now evaluate them numerically to eyeball them rectform(subst),numer -- Surprise! Only 6 of the 12 are right. And it is completely missing the parametric solution(s)!!! For example, a= 2 / ( sqrt( Q^4-4*Q ) - Q^2 ) b= ( sqrt( Q^4-4*Q ) - Q^2 ) / (2*Q) c= Q ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=611129&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-611129 ] Egregious bug in Solve/Algsys From: SourceForge.net - 2006-06-26 18:22:31 ```Bugs item #611129, was opened at 2002-09-18 08:52 Message generated for change (Comment added) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=611129&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: Egregious bug in Solve/Algsys Initial Comment: In a very simple case, Solve/Algsys (a) reports many incorrect solutions and (b) misses all the parameterized solutions. -- Define equations eqs: [a+b+c=0, a*b*c=1] -- These seem pretty simple, don't they? -- Solve 2 equations for 3 unknowns (normal algsys) sols: solve(eqs,[a,b,c]) -- Gives 12 solutions -- Substitute back the solutions subst: map(lambda([sol],subst(sol,eqs)),sols) -- Big mess -- Now evaluate them numerically to eyeball them rectform(subst),numer -- Surprise! Only 6 of the 12 are right. And it is completely missing the parametric solution(s)!!! For example, a= 2 / ( sqrt( Q^4-4*Q ) - Q^2 ) b= ( sqrt( Q^4-4*Q ) - Q^2 ) / (2*Q) c= Q ---------------------------------------------------------------------- >Comment By: Robert Dodier (robert_dodier) Date: 2006-06-26 12:22 Message: Logged In: YES user_id=501686 Observed in 5.9.3. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=611129&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-611129 ] Egregious bug in Solve/Algsys From: SourceForge.net - 2006-08-27 00:20:21 ```Bugs item #611129, was opened at 2002-09-18 08:52 Message generated for change (Settings changed) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=611129&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 - Solving equations Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Egregious bug in Solve/Algsys Initial Comment: In a very simple case, Solve/Algsys (a) reports many incorrect solutions and (b) misses all the parameterized solutions. -- Define equations eqs: [a+b+c=0, a*b*c=1] -- These seem pretty simple, don't they? -- Solve 2 equations for 3 unknowns (normal algsys) sols: solve(eqs,[a,b,c]) -- Gives 12 solutions -- Substitute back the solutions subst: map(lambda([sol],subst(sol,eqs)),sols) -- Big mess -- Now evaluate them numerically to eyeball them rectform(subst),numer -- Surprise! Only 6 of the 12 are right. And it is completely missing the parametric solution(s)!!! For example, a= 2 / ( sqrt( Q^4-4*Q ) - Q^2 ) b= ( sqrt( Q^4-4*Q ) - Q^2 ) / (2*Q) c= Q ---------------------------------------------------------------------- Comment By: Robert Dodier (robert_dodier) Date: 2006-06-26 12:22 Message: Logged In: YES user_id=501686 Observed in 5.9.3. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=611129&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-611129 ] Egregious bug in Solve/Algsys From: SourceForge.net - 2008-10-02 10:37:06 ```Bugs item #611129, was opened at 2002-09-18 09:52 Message generated for change (Comment added) made by willisbl You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=611129&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 - Solving equations Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Egregious bug in Solve/Algsys Initial Comment: In a very simple case, Solve/Algsys (a) reports many incorrect solutions and (b) misses all the parameterized solutions. -- Define equations eqs: [a+b+c=0, a*b*c=1] -- These seem pretty simple, don't they? -- Solve 2 equations for 3 unknowns (normal algsys) sols: solve(eqs,[a,b,c]) -- Gives 12 solutions -- Substitute back the solutions subst: map(lambda([sol],subst(sol,eqs)),sols) -- Big mess -- Now evaluate them numerically to eyeball them rectform(subst),numer -- Surprise! Only 6 of the 12 are right. And it is completely missing the parametric solution(s)!!! For example, a= 2 / ( sqrt( Q^4-4*Q ) - Q^2 ) b= ( sqrt( Q^4-4*Q ) - Q^2 ) / (2*Q) c= Q ---------------------------------------------------------------------- >Comment By: Barton Willis (willisbl) Date: 2008-10-02 05:37 Message: With algebraic : true, we get another bug: (%i34) eqs: [a+b+c=0, a*b*c=1]; (%o34) [c+b+a=0,a*b*c=1] (%i35) algsys(eqs,[a,b,c]), algebraic : true; Quotient by a polynomial of higher degree -- an error. To debug this try debugmode(true); ---------------------------------------------------------------------- Comment By: Robert Dodier (robert_dodier) Date: 2006-06-26 13:22 Message: Logged In: YES user_id=501686 Observed in 5.9.3. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=611129&group_id=4933 ```