From: SourceForge.net <noreply@so...>  20120615 14:05:32

Bugs item #3535473, was opened at 20120615 07:05 Message generated for change (Tracker Item Submitted) made by chrisrein You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3535473&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: christoph reineke (chrisrein) Assigned to: Nobody/Anonymous (nobody) Summary: Simplification/Infinite sum Initial Comment: Enter in Maxima: simplify_sum(sum(n^2/(2*n)!,n,1,inf)); Maxima returns: (sqrt(%pi)*(sqrt(2)*bessel_i(3/2,1)+2^(3/2)*bessel_i(1/2,1)))/8 Maxima should return: %e/4 build_info("5.27.0","20120424 08:52:03","i686pcmingw32","GNU Common Lisp (GCL)","GCL 2.6.8") Regards Chris  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3535473&group_id=4933 
From: SourceForge.net <noreply@so...>  20120615 17:51:58

Bugs item #3535473, was opened at 20120615 07:05 Message generated for change (Comment added) made by rtoy You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3535473&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: Pending >Resolution: Wont Fix Priority: 5 Private: No Submitted By: christoph reineke (chrisrein) Assigned to: Nobody/Anonymous (nobody) Summary: Simplification/Infinite sum Initial Comment: Enter in Maxima: simplify_sum(sum(n^2/(2*n)!,n,1,inf)); Maxima returns: (sqrt(%pi)*(sqrt(2)*bessel_i(3/2,1)+2^(3/2)*bessel_i(1/2,1)))/8 Maxima should return: %e/4 build_info("5.27.0","20120424 08:52:03","i686pcmingw32","GNU Common Lisp (GCL)","GCL 2.6.8") Regards Chris  >Comment By: Raymond Toy (rtoy) Date: 20120615 10:51 Message: expand(exponentialize(ev(%,besselexpand=true))) > %e/4 I only knew to try this because bessel_i with half integer orders have representations in elementary functions, which you get by setting besselexpand to true. Marking as pending/wontfix  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3535473&group_id=4933 
From: SourceForge.net <noreply@so...>  20120616 11:19:57

Bugs item #3535473, was opened at 20120615 07:05 Message generated for change (Comment added) made by chrisrein You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3535473&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: Wont Fix Priority: 5 Private: No Submitted By: christoph reineke (chrisrein) Assigned to: Nobody/Anonymous (nobody) Summary: Simplification/Infinite sum Initial Comment: Enter in Maxima: simplify_sum(sum(n^2/(2*n)!,n,1,inf)); Maxima returns: (sqrt(%pi)*(sqrt(2)*bessel_i(3/2,1)+2^(3/2)*bessel_i(1/2,1)))/8 Maxima should return: %e/4 build_info("5.27.0","20120424 08:52:03","i686pcmingw32","GNU Common Lisp (GCL)","GCL 2.6.8") Regards Chris  >Comment By: christoph reineke (chrisrein) Date: 20120616 04:19 Message: Thanks for your help! Yes, if you are a specialist, it’s quite simple. If not, you have a problem. First you notice that all simplifications in the pull down menu of wx Maxima fail. Then you have to read a chapter about Bessel functions until you find “besselexpand”. After applying “besselexpand”, Maxima returns a sum of hyperbolic functions. Now you need “exponentialize” to get a sum of e functions and finally you see %e/4. Why do I have to do all these things? If I enter sum(n^2/(2*n)!,n,1,inf) in Wolfram Alpha I immediately get the correct result. <marking as pending/wontfix> Ok. Thanks again Chris  Comment By: Raymond Toy (rtoy) Date: 20120615 10:51 Message: expand(exponentialize(ev(%,besselexpand=true))) > %e/4 I only knew to try this because bessel_i with half integer orders have representations in elementary functions, which you get by setting besselexpand to true. Marking as pending/wontfix  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3535473&group_id=4933 
From: SourceForge.net <noreply@so...>  20120620 07:00:58

Bugs item #3535473, was opened at 20120615 07:05 Message generated for change (Comment added) made by rtoy You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3535473&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: Wont Fix Priority: 5 Private: No Submitted By: christoph reineke (chrisrein) Assigned to: Nobody/Anonymous (nobody) Summary: Simplification/Infinite sum Initial Comment: Enter in Maxima: simplify_sum(sum(n^2/(2*n)!,n,1,inf)); Maxima returns: (sqrt(%pi)*(sqrt(2)*bessel_i(3/2,1)+2^(3/2)*bessel_i(1/2,1)))/8 Maxima should return: %e/4 build_info("5.27.0","20120424 08:52:03","i686pcmingw32","GNU Common Lisp (GCL)","GCL 2.6.8") Regards Chris  >Comment By: Raymond Toy (rtoy) Date: 20120620 00:00 Message: I think it's very hard in general to know what the right answer should be. Yes %e/4 is a very simple answer. But sometimes it's also nice to know that the sum can be expressed in terms of bessel_i, which might lead to insight into other similar sums. If maxima simplified to %e/4, you wouldn't know about bessel_i, possibly missing out on the insight. But it's also nice to know that maxima can simplify the result to %e/4, for the case where you don't care about the insight. :)  Comment By: christoph reineke (chrisrein) Date: 20120616 04:19 Message: Thanks for your help! Yes, if you are a specialist, it’s quite simple. If not, you have a problem. First you notice that all simplifications in the pull down menu of wx Maxima fail. Then you have to read a chapter about Bessel functions until you find “besselexpand”. After applying “besselexpand”, Maxima returns a sum of hyperbolic functions. Now you need “exponentialize” to get a sum of e functions and finally you see %e/4. Why do I have to do all these things? If I enter sum(n^2/(2*n)!,n,1,inf) in Wolfram Alpha I immediately get the correct result. <marking as pending/wontfix> Ok. Thanks again Chris  Comment By: Raymond Toy (rtoy) Date: 20120615 10:51 Message: expand(exponentialize(ev(%,besselexpand=true))) > %e/4 I only knew to try this because bessel_i with half integer orders have representations in elementary functions, which you get by setting besselexpand to true. Marking as pending/wontfix  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3535473&group_id=4933 