From: SourceForge.net <no...@so...> - 2004-04-15 19:40:54
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Bugs item #935030, was opened at 2004-04-14 11:17 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=935030&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Barton Willis (willisbl) Assigned to: Nobody/Anonymous (nobody) Summary: ratsimp with algebraic == true Initial Comment: With algebraic == true, ratsimp doesn't fully simplify some expressions. Here is an example (C1) display2d : false$ (C2) algebraic : true$ (C3) integrate(1/(2+x^3),x)$ (C4) ratsimp(diff(%,x)); (D4) 4*2^(2/3)/(4*2^(2/3)*x^3+8*2^(2/3)) (C5) ratsimp(%); (D5) 1/(x^3+2) Maybe this is the purpose of fullratsimp, but it seems odd that ratsimp fails to cancel the factor of 2^(2/3). I discovered this when I ran run_testsuite with algebraic == true. (C6) build_info(); Maxima version: 5.9.0.1cvs Maxima build date: 7:58 4/5/2004 host type: i686-pc-mingw32 lisp-implementation-type: Kyoto Common Lisp lisp-implementation-version: GCL 2.7.0 Barton ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=935030&group_id=4933 |
From: SourceForge.net <no...@so...> - 2004-04-19 19:55:20
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Bugs item #935030, was opened at 2004-04-14 12:17 Message generated for change (Comment added) made by macrakis You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=935030&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Barton Willis (willisbl) Assigned to: Nobody/Anonymous (nobody) Summary: ratsimp with algebraic == true Initial Comment: With algebraic == true, ratsimp doesn't fully simplify some expressions. Here is an example (C1) display2d : false$ (C2) algebraic : true$ (C3) integrate(1/(2+x^3),x)$ (C4) ratsimp(diff(%,x)); (D4) 4*2^(2/3)/(4*2^(2/3)*x^3+8*2^(2/3)) (C5) ratsimp(%); (D5) 1/(x^3+2) Maybe this is the purpose of fullratsimp, but it seems odd that ratsimp fails to cancel the factor of 2^(2/3). I discovered this when I ran run_testsuite with algebraic == true. (C6) build_info(); Maxima version: 5.9.0.1cvs Maxima build date: 7:58 4/5/2004 host type: i686-pc-mingw32 lisp-implementation-type: Kyoto Common Lisp lisp-implementation-version: GCL 2.7.0 Barton ---------------------------------------------------------------------- >Comment By: Stavros Macrakis (macrakis) Date: 2004-04-19 15:55 Message: Logged In: YES user_id=588346 Though this is annoying and surprising, it *is* documented: >>>>>>>>>(fullratsimp) When non-rational expressions are involved, one call to RATSIMP followed as is usual by non-rational ("general") simplification may not be sufficient to return a simplified result. <<<<<<<<< Also, the algebraic flag only changes the behavior with gcd=spmod. With gcd=subres (the default), you need two ratsimp's regardless of the setting of algebraic. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=935030&group_id=4933 |
From: SourceForge.net <no...@so...> - 2006-07-29 06:13:55
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Bugs item #935030, was opened at 2004-04-14 10:17 Message generated for change (Comment added) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=935030&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 - Simplification Group: None Status: Open Resolution: None Priority: 5 Submitted By: Barton Willis (willisbl) Assigned to: Nobody/Anonymous (nobody) Summary: ratsimp with algebraic == true Initial Comment: With algebraic == true, ratsimp doesn't fully simplify some expressions. Here is an example (C1) display2d : false$ (C2) algebraic : true$ (C3) integrate(1/(2+x^3),x)$ (C4) ratsimp(diff(%,x)); (D4) 4*2^(2/3)/(4*2^(2/3)*x^3+8*2^(2/3)) (C5) ratsimp(%); (D5) 1/(x^3+2) Maybe this is the purpose of fullratsimp, but it seems odd that ratsimp fails to cancel the factor of 2^(2/3). I discovered this when I ran run_testsuite with algebraic == true. (C6) build_info(); Maxima version: 5.9.0.1cvs Maxima build date: 7:58 4/5/2004 host type: i686-pc-mingw32 lisp-implementation-type: Kyoto Common Lisp lisp-implementation-version: GCL 2.7.0 Barton ---------------------------------------------------------------------- >Comment By: Robert Dodier (robert_dodier) Date: 2006-07-29 00:13 Message: Logged In: YES user_id=501686 Observed in 5.9.3cvs. ---------------------------------------------------------------------- Comment By: Stavros Macrakis (macrakis) Date: 2004-04-19 13:55 Message: Logged In: YES user_id=588346 Though this is annoying and surprising, it *is* documented: >>>>>>>>>(fullratsimp) When non-rational expressions are involved, one call to RATSIMP followed as is usual by non-rational ("general") simplification may not be sufficient to return a simplified result. <<<<<<<<< Also, the algebraic flag only changes the behavior with gcd=spmod. With gcd=subres (the default), you need two ratsimp's regardless of the setting of algebraic. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=935030&group_id=4933 |
From: SourceForge.net <no...@so...> - 2010-03-20 01:32:37
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Bugs item #935030, was opened at 2004-04-14 18:17 Message generated for change (Settings changed) made by crategus You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=935030&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 - Simplification Group: None >Status: Closed >Resolution: Works For Me Priority: 5 Private: No Submitted By: Barton Willis (willisbl) Assigned to: Nobody/Anonymous (nobody) Summary: ratsimp with algebraic == true Initial Comment: With algebraic == true, ratsimp doesn't fully simplify some expressions. Here is an example (C1) display2d : false$ (C2) algebraic : true$ (C3) integrate(1/(2+x^3),x)$ (C4) ratsimp(diff(%,x)); (D4) 4*2^(2/3)/(4*2^(2/3)*x^3+8*2^(2/3)) (C5) ratsimp(%); (D5) 1/(x^3+2) Maybe this is the purpose of fullratsimp, but it seems odd that ratsimp fails to cancel the factor of 2^(2/3). I discovered this when I ran run_testsuite with algebraic == true. (C6) build_info(); Maxima version: 5.9.0.1cvs Maxima build date: 7:58 4/5/2004 host type: i686-pc-mingw32 lisp-implementation-type: Kyoto Common Lisp lisp-implementation-version: GCL 2.7.0 Barton ---------------------------------------------------------------------- >Comment By: Dieter Kaiser (crategus) Date: 2010-03-20 02:32 Message: This behavior is no longer present in Maxima 5.20post: (%i1) algebraic:true; (%o1) true (%i2) integrate(1/(2+x^3),x); (%o2) -log(2^(2/3)*x^2-2*x+2^(4/3))/(3*2^(5/3)) +atan((2^(5/3)*x-2)/(2*sqrt(3)))/(2^(2/3)*sqrt(3)) +log(x+2^(1/3))/(3*2^(2/3)) (%i3) ratsimp(diff(%,x)); (%o3) 1/(x^3+2) This works for algebraic:false the same way. We get immediately a fully simplified and correct result from ratsimp. The reason might be that the simplification of powers of integers has been implemented more consistent the last year. Closing this bug report as "Works for me". Dieter Kaiser ---------------------------------------------------------------------- Comment By: Robert Dodier (robert_dodier) Date: 2006-07-29 08:13 Message: Logged In: YES user_id=501686 Observed in 5.9.3cvs. ---------------------------------------------------------------------- Comment By: Stavros Macrakis (macrakis) Date: 2004-04-19 21:55 Message: Logged In: YES user_id=588346 Though this is annoying and surprising, it *is* documented: >>>>>>>>>(fullratsimp) When non-rational expressions are involved, one call to RATSIMP followed as is usual by non-rational ("general") simplification may not be sufficient to return a simplified result. <<<<<<<<< Also, the algebraic flag only changes the behavior with gcd=spmod. With gcd=subres (the default), you need two ratsimp's regardless of the setting of algebraic. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=935030&group_id=4933 |