## [Maxima-bugs] [ maxima-Bugs-3529992 ] Shi (sinh integral) wrong branch, integrate inconsisten

 [Maxima-bugs] [ maxima-Bugs-3529992 ] Shi (sinh integral) wrong branch, integrate inconsisten From: SourceForge.net - 2012-05-27 16:46:44 ```Bugs item #3529992, was opened at 2012-05-26 11:06 Message generated for change (Settings changed) made by rtoy You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3529992&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 - Floating point Group: None >Status: Closed >Resolution: Fixed Priority: 5 Private: No Submitted By: https://www.google.com/accounts () Assigned to: Nobody/Anonymous (nobody) Summary: Shi (sinh integral) wrong branch, integrate inconsisten Initial Comment: Note that expintegral_shi(x) is a real function - see A&S or Wolfram Alpha. http://www.wolframalpha.com/input/?i=integrate+Shi%28x%29+from+0+to+1%2F2 gives about .125872409 as does mpmath. (%i11) expand(float(integrate(expintegral_shi(x),x,0,1/2))); (%o11) 1.5707963267948966*%i+.12587240970345281 Extra pi/2? This come from (%i30) float(expintegral_shi(1/2)); (%o30) 3.141592653589793*%i+0.506996749819667 So Maxima is, oddly, using a different branch for this function even though they cite The Exponential Integral Shi(z) (A&S 5.2.3) and http://people.math.sfu.ca/~cbm/aands/page_231.htm clearly makes this something that should be real. See http://trac.sagemath.org/sage_trac/ticket/11143 where this was first noticed. ---------------------------------------------------------------------- >Comment By: Raymond Toy (rtoy) Date: 2012-05-27 09:46 Message: Fixed in git. Thanks for the report. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3529992&group_id=4933 ```

 [Maxima-bugs] [ maxima-Bugs-3529992 ] Shi (sinh integral) wrong branch, integrate inconsisten From: SourceForge.net - 2012-05-26 18:06:38 ```Bugs item #3529992, was opened at 2012-05-26 11:06 Message generated for change (Tracker Item Submitted) made by You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3529992&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 Private: No Submitted By: https://www.google.com/accounts () Assigned to: Nobody/Anonymous (nobody) Summary: Shi (sinh integral) wrong branch, integrate inconsisten Initial Comment: Note that expintegral_shi(x) is a real function - see A&S or Wolfram Alpha. http://www.wolframalpha.com/input/?i=integrate+Shi%28x%29+from+0+to+1%2F2 gives about .125872409 as does mpmath. (%i11) expand(float(integrate(expintegral_shi(x),x,0,1/2))); (%o11) 1.5707963267948966*%i+.12587240970345281 Extra pi/2? This come from (%i30) float(expintegral_shi(1/2)); (%o30) 3.141592653589793*%i+0.506996749819667 So Maxima is, oddly, using a different branch for this function even though they cite The Exponential Integral Shi(z) (A&S 5.2.3) and http://people.math.sfu.ca/~cbm/aands/page_231.htm clearly makes this something that should be real. See http://trac.sagemath.org/sage_trac/ticket/11143 where this was first noticed. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3529992&group_id=4933 ```
 [Maxima-bugs] [ maxima-Bugs-3529992 ] Shi (sinh integral) wrong branch, integrate inconsisten From: SourceForge.net - 2012-05-27 16:46:44 ```Bugs item #3529992, was opened at 2012-05-26 11:06 Message generated for change (Settings changed) made by rtoy You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3529992&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 - Floating point Group: None >Status: Closed >Resolution: Fixed Priority: 5 Private: No Submitted By: https://www.google.com/accounts () Assigned to: Nobody/Anonymous (nobody) Summary: Shi (sinh integral) wrong branch, integrate inconsisten Initial Comment: Note that expintegral_shi(x) is a real function - see A&S or Wolfram Alpha. http://www.wolframalpha.com/input/?i=integrate+Shi%28x%29+from+0+to+1%2F2 gives about .125872409 as does mpmath. (%i11) expand(float(integrate(expintegral_shi(x),x,0,1/2))); (%o11) 1.5707963267948966*%i+.12587240970345281 Extra pi/2? This come from (%i30) float(expintegral_shi(1/2)); (%o30) 3.141592653589793*%i+0.506996749819667 So Maxima is, oddly, using a different branch for this function even though they cite The Exponential Integral Shi(z) (A&S 5.2.3) and http://people.math.sfu.ca/~cbm/aands/page_231.htm clearly makes this something that should be real. See http://trac.sagemath.org/sage_trac/ticket/11143 where this was first noticed. ---------------------------------------------------------------------- >Comment By: Raymond Toy (rtoy) Date: 2012-05-27 09:46 Message: Fixed in git. Thanks for the report. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=3529992&group_id=4933 ```