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## [Maxima-bugs] [ maxima-Bugs-3034049 ] Elementary Algsys/Solve bug

 [Maxima-bugs] [ maxima-Bugs-3034049 ] Elementary Algsys/Solve bug From: SourceForge.net - 2010-07-24 15:44:41 ```Bugs item #3034049, was opened at 2010-07-24 11:41 Message generated for change (Comment added) made by macrakis You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3034049&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: 7 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Elementary Algsys/Solve bug Initial Comment: eqs: [y^2+x^2-(400-400/(2/q+1))^2 = 0,(-y-400/(2/q+1)+400)^2+x^2-640000/(2/q+1)^2 = 0] solve(eqs,[x,y]) gives correct solution, but solve(subst(sqrt(3),q,eqs),[x,y]) yields []! A possibly related case: eqt: [y^2+x^2-1,y^2+(1-sqrt(3))*y+x^2+2] algsys(eqt,[x,y]) => good solutions solve(eqt,[x,y]) => [] ---------------------------------------------------------------------- >Comment By: Stavros Macrakis (macrakis) Date: 2010-07-24 11:44 Message: observed in Maxima 5.21.1 http://maxima.sourceforge.net using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (a.k.a. GCL) ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3034049&group_id=4933 ```

 [Maxima-bugs] [ maxima-Bugs-3034049 ] Elementary Algsys/Solve bug From: SourceForge.net - 2010-07-24 15:41:58 ```Bugs item #3034049, was opened at 2010-07-24 11:41 Message generated for change (Tracker Item Submitted) made by macrakis You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3034049&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: 7 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Elementary Algsys/Solve bug Initial Comment: eqs: [y^2+x^2-(400-400/(2/q+1))^2 = 0,(-y-400/(2/q+1)+400)^2+x^2-640000/(2/q+1)^2 = 0] solve(eqs,[x,y]) gives correct solution, but solve(subst(sqrt(3),q,eqs),[x,y]) yields []! A possibly related case: eqt: [y^2+x^2-1,y^2+(1-sqrt(3))*y+x^2+2] algsys(eqt,[x,y]) => good solutions solve(eqt,[x,y]) => [] ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3034049&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-3034049 ] Elementary Algsys/Solve bug From: SourceForge.net - 2010-07-24 15:44:41 ```Bugs item #3034049, was opened at 2010-07-24 11:41 Message generated for change (Comment added) made by macrakis You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3034049&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: 7 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Elementary Algsys/Solve bug Initial Comment: eqs: [y^2+x^2-(400-400/(2/q+1))^2 = 0,(-y-400/(2/q+1)+400)^2+x^2-640000/(2/q+1)^2 = 0] solve(eqs,[x,y]) gives correct solution, but solve(subst(sqrt(3),q,eqs),[x,y]) yields []! A possibly related case: eqt: [y^2+x^2-1,y^2+(1-sqrt(3))*y+x^2+2] algsys(eqt,[x,y]) => good solutions solve(eqt,[x,y]) => [] ---------------------------------------------------------------------- >Comment By: Stavros Macrakis (macrakis) Date: 2010-07-24 11:44 Message: observed in Maxima 5.21.1 http://maxima.sourceforge.net using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (a.k.a. GCL) ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3034049&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-3034049 ] Elementary Algsys/Solve bug From: SourceForge.net - 2010-07-24 16:46:11 ```Bugs item #3034049, was opened at 2010-07-24 10:41 Message generated for change (Comment added) made by willisbl You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3034049&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: 7 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Elementary Algsys/Solve bug Initial Comment: eqs: [y^2+x^2-(400-400/(2/q+1))^2 = 0,(-y-400/(2/q+1)+400)^2+x^2-640000/(2/q+1)^2 = 0] solve(eqs,[x,y]) gives correct solution, but solve(subst(sqrt(3),q,eqs),[x,y]) yields []! A possibly related case: eqt: [y^2+x^2-1,y^2+(1-sqrt(3))*y+x^2+2] algsys(eqt,[x,y]) => good solutions solve(eqt,[x,y]) => [] ---------------------------------------------------------------------- >Comment By: Barton Willis (willisbl) Date: 2010-07-24 11:46 Message: Setting algebraic to true is *not* a workaround. Maxima is unable to even solve a triangular form of these equations; of course, the triangular form may have spurious solutions. This is a high priority bug. (%i1) algebraic : true\$ (%i2) load(to_poly_solver)\$ (%i3) eqs: [y^2+x^2-(400-400/(2/q+1))^2 = 0,(-y-400/(2/q+1)+400)^2+x^2-640000/(2/q+1)^2 = 0]\$ (%i4) eqs : subst(q = sqrt(3),eqs)\$ (%i5) eqs : radcan(ratnumer(eqs)); (%o5) [y^2+x^2+2560000*sqrt(3)-4480000=0,y^2+(1600*sqrt(3)-3200)*y+x^2+5120000*sqrt(3)-8960000=0] (%i6) eqs : elim(eqs,[y,x]); (%o6) [[],[4*sqrt(3)*y^2-7*y^2+4000*3^(3/2)*y-20800*y+8960000*sqrt(3)-15520000,y^2+x^2+2560000*sqrt(3)-4480000]] (%i7) eqs : second(eqs); (%o7) [4*sqrt(3)*y^2-7*y^2+4000*3^(3/2)*y-20800*y+8960000*sqrt(3)-15520000,y^2+x^2+2560000*sqrt(3)-4480000] (%i8) solve(eqs,[x,y]); (%o8) [] (%i9) solve(first(eqs),y); (%o9) [y=400*sqrt(3)-800] ---------------------------------------------------------------------- Comment By: Stavros Macrakis (macrakis) Date: 2010-07-24 10:44 Message: observed in Maxima 5.21.1 http://maxima.sourceforge.net using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (a.k.a. GCL) ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3034049&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-3034049 ] Elementary Algsys/Solve bug From: SourceForge.net - 2010-07-24 20:04:54 ```Bugs item #3034049, was opened at 2010-07-24 11:41 Message generated for change (Comment added) made by macrakis You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3034049&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: 7 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Elementary Algsys/Solve bug Initial Comment: eqs: [y^2+x^2-(400-400/(2/q+1))^2 = 0,(-y-400/(2/q+1)+400)^2+x^2-640000/(2/q+1)^2 = 0] solve(eqs,[x,y]) gives correct solution, but solve(subst(sqrt(3),q,eqs),[x,y]) yields []! A possibly related case: eqt: [y^2+x^2-1,y^2+(1-sqrt(3))*y+x^2+2] algsys(eqt,[x,y]) => good solutions solve(eqt,[x,y]) => [] ---------------------------------------------------------------------- >Comment By: Stavros Macrakis (macrakis) Date: 2010-07-24 16:04 Message: Just plain solve(eqs) and solve(eqt) work fine. ---------------------------------------------------------------------- Comment By: Barton Willis (willisbl) Date: 2010-07-24 12:46 Message: Setting algebraic to true is *not* a workaround. Maxima is unable to even solve a triangular form of these equations; of course, the triangular form may have spurious solutions. This is a high priority bug. (%i1) algebraic : true\$ (%i2) load(to_poly_solver)\$ (%i3) eqs: [y^2+x^2-(400-400/(2/q+1))^2 = 0,(-y-400/(2/q+1)+400)^2+x^2-640000/(2/q+1)^2 = 0]\$ (%i4) eqs : subst(q = sqrt(3),eqs)\$ (%i5) eqs : radcan(ratnumer(eqs)); (%o5) [y^2+x^2+2560000*sqrt(3)-4480000=0,y^2+(1600*sqrt(3)-3200)*y+x^2+5120000*sqrt(3)-8960000=0] (%i6) eqs : elim(eqs,[y,x]); (%o6) [[],[4*sqrt(3)*y^2-7*y^2+4000*3^(3/2)*y-20800*y+8960000*sqrt(3)-15520000,y^2+x^2+2560000*sqrt(3)-4480000]] (%i7) eqs : second(eqs); (%o7) [4*sqrt(3)*y^2-7*y^2+4000*3^(3/2)*y-20800*y+8960000*sqrt(3)-15520000,y^2+x^2+2560000*sqrt(3)-4480000] (%i8) solve(eqs,[x,y]); (%o8) [] (%i9) solve(first(eqs),y); (%o9) [y=400*sqrt(3)-800] ---------------------------------------------------------------------- Comment By: Stavros Macrakis (macrakis) Date: 2010-07-24 11:44 Message: observed in Maxima 5.21.1 http://maxima.sourceforge.net using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (a.k.a. GCL) ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3034049&group_id=4933 ```