From: SourceForge.net <noreply@so...>  20060921 07:07:17

Bugs item #1562671, was opened at 20060921 09:07 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=1562671&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: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Elmar Zander (zandere) Assigned to: Nobody/Anonymous (nobody) Summary: Handling of infinities Initial Comment: The handling of inf seems to be like that of a really huge (bigger than everything else) but otherwise specific number. Some examples: infinf => 0 inf/inf => 1 inf*0 => 0 Those should all return "undefined". In the following cases the return value should be directly simplified to inf again inf*inf => inf^2 inf+inf => 2*inf 4*inf => 4*inf Also comparisons like the following should be undefined: is( inf>=inf ) => true if( inf>=2*inf ) => false Furthermore there is no relation between inf and minf: inf => inf minf => minf inf+minf => inf+minf Those should return minf, inf, and und respectively. It would be nice if infinities would be handled like in the IEEE floating point standard which, I think, makes more sense in those cases.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1562671&group_id=4933 
From: SourceForge.net <noreply@so...>  20061204 23:51:01

Bugs item #1562671, was opened at 20060921 03:07 Message generated for change (Comment added) made by macrakis You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1562671&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: None Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Elmar Zander (zandere) Assigned to: Nobody/Anonymous (nobody) Summary: Handling of infinities Initial Comment: The handling of inf seems to be like that of a really huge (bigger than everything else) but otherwise specific number. Some examples: infinf => 0 inf/inf => 1 inf*0 => 0 Those should all return "undefined". In the following cases the return value should be directly simplified to inf again inf*inf => inf^2 inf+inf => 2*inf 4*inf => 4*inf Also comparisons like the following should be undefined: is( inf>=inf ) => true if( inf>=2*inf ) => false Furthermore there is no relation between inf and minf: inf => inf minf => minf inf+minf => inf+minf Those should return minf, inf, and und respectively. It would be nice if infinities would be handled like in the IEEE floating point standard which, I think, makes more sense in those cases.  >Comment By: Stavros Macrakis (macrakis) Date: 20061204 18:50 Message: Logged In: YES user_id=588346 Originator: NO Yes, these limitations are known. Basically, the only parts of Maxima that know about inf/minf/und/ind/infinity are the limit and definite integral packages. As far as the rest of Maxima is concerned, INF is just a variable like X. This is silly, of course. The problem is that correcting this in the obvious way means special cases throughout the simplification code, which assumes that if two identifiers are the same identifier, they are equal.... There are other possible solutions (e.g. making each infinity produced unique in some way), but they have their complications, too....  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1562671&group_id=4933 
From: SourceForge.net <noreply@so...>  20061226 21:32:41

Bugs item #1562671, was opened at 20060921 01:07 Message generated for change (Settings changed) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1562671&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 Private: No Submitted By: Elmar Zander (zandere) Assigned to: Nobody/Anonymous (nobody) Summary: Handling of infinities Initial Comment: The handling of inf seems to be like that of a really huge (bigger than everything else) but otherwise specific number. Some examples: infinf => 0 inf/inf => 1 inf*0 => 0 Those should all return "undefined". In the following cases the return value should be directly simplified to inf again inf*inf => inf^2 inf+inf => 2*inf 4*inf => 4*inf Also comparisons like the following should be undefined: is( inf>=inf ) => true if( inf>=2*inf ) => false Furthermore there is no relation between inf and minf: inf => inf minf => minf inf+minf => inf+minf Those should return minf, inf, and und respectively. It would be nice if infinities would be handled like in the IEEE floating point standard which, I think, makes more sense in those cases.  Comment By: Stavros Macrakis (macrakis) Date: 20061204 16:50 Message: Logged In: YES user_id=588346 Originator: NO Yes, these limitations are known. Basically, the only parts of Maxima that know about inf/minf/und/ind/infinity are the limit and definite integral packages. As far as the rest of Maxima is concerned, INF is just a variable like X. This is silly, of course. The problem is that correcting this in the obvious way means special cases throughout the simplification code, which assumes that if two identifiers are the same identifier, they are equal.... There are other possible solutions (e.g. making each infinity produced unique in some way), but they have their complications, too....  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1562671&group_id=4933 
From: SourceForge.net <noreply@so...>  20080405 22:31:33

Bugs item #1562671, was opened at 20060921 01:07 Message generated for change (Settings changed) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1562671&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: 7 Private: No Submitted By: Elmar Zander (zandere) Assigned to: Nobody/Anonymous (nobody) Summary: Handling of infinities Initial Comment: The handling of inf seems to be like that of a really huge (bigger than everything else) but otherwise specific number. Some examples: infinf => 0 inf/inf => 1 inf*0 => 0 Those should all return "undefined". In the following cases the return value should be directly simplified to inf again inf*inf => inf^2 inf+inf => 2*inf 4*inf => 4*inf Also comparisons like the following should be undefined: is( inf>=inf ) => true if( inf>=2*inf ) => false Furthermore there is no relation between inf and minf: inf => inf minf => minf inf+minf => inf+minf Those should return minf, inf, and und respectively. It would be nice if infinities would be handled like in the IEEE floating point standard which, I think, makes more sense in those cases.  >Comment By: Robert Dodier (robert_dodier) Date: 20080405 16:31 Message: Logged In: YES user_id=501686 Originator: NO Increasing the priority of this item.  Comment By: Stavros Macrakis (macrakis) Date: 20061204 16:50 Message: Logged In: YES user_id=588346 Originator: NO Yes, these limitations are known. Basically, the only parts of Maxima that know about inf/minf/und/ind/infinity are the limit and definite integral packages. As far as the rest of Maxima is concerned, INF is just a variable like X. This is silly, of course. The problem is that correcting this in the obvious way means special cases throughout the simplification code, which assumes that if two identifiers are the same identifier, they are equal.... There are other possible solutions (e.g. making each infinity produced unique in some way), but they have their complications, too....  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1562671&group_id=4933 