From: SourceForge.net <noreply@so...>  20040310 03:29:04

Bugs item #913239, was opened at 20040309 22:11 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=913239&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Integral with erf wrong (multiplicative constant off) Initial Comment: integrate(exp(k*t)/sqrt(k*t),t) => SQRT(%PI) k ERF(SQRT(k t)) should be SQRT(%PI) ERF(SQRT(k t)) /k Reported by Kevin Ellwood (kellwood@...) on the Maxima mailing list Tue 2004Mar09 17:38 "I found a few other integrals involving erf() that had similar error in carrying constants through." Macrakis confirms on Maxima 5.9.0 gcl 2.5.0 W2k Fateman reports that this bug is fixed in commercial Macsyma.  Original bug report email I am not to sure if this is a know issue (or if I did something wrong) but I think I found a small bug. I was doing some work with maxima (5.9) in which I was checking my own calculations and I discovered that it got the wrong answer for: (C1) integrate(exp(k*t)/sqrt(k*t),t); (D1) SQRT(%PI) k ERF(SQRT(k t)) The correct answer is: SQRT(%PI) ERF(SQRT(k t)) /k As is shown here: (C3) derivative(sqrt(%PI)/k*erf(sqrt(k*t)),t);  k t %E (D3)  SQRT(k t) Maxima got the hard part correct but failed to carry "k" through the integration correctly. I found a few other integrals involving erf() that had similar error in carrying constants through.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=913239&group_id=4933 
From: SourceForge.net <noreply@so...>  20051210 02:31:38

Bugs item #913239, was opened at 20040309 22:11 Message generated for change (Comment added) made by rtoy You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=913239&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: Closed >Resolution: Fixed Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: Integral with erf wrong (multiplicative constant off) Initial Comment: integrate(exp(k*t)/sqrt(k*t),t) => SQRT(%PI) k ERF(SQRT(k t)) should be SQRT(%PI) ERF(SQRT(k t)) /k Reported by Kevin Ellwood (kellwood@...) on the Maxima mailing list Tue 2004Mar09 17:38 "I found a few other integrals involving erf() that had similar error in carrying constants through." Macrakis confirms on Maxima 5.9.0 gcl 2.5.0 W2k Fateman reports that this bug is fixed in commercial Macsyma.  Original bug report email I am not to sure if this is a know issue (or if I did something wrong) but I think I found a small bug. I was doing some work with maxima (5.9) in which I was checking my own calculations and I discovered that it got the wrong answer for: (C1) integrate(exp(k*t)/sqrt(k*t),t); (D1) SQRT(%PI) k ERF(SQRT(k t)) The correct answer is: SQRT(%PI) ERF(SQRT(k t)) /k As is shown here: (C3) derivative(sqrt(%PI)/k*erf(sqrt(k*t)),t);  k t %E (D3)  SQRT(k t) Maxima got the hard part correct but failed to carry "k" through the integration correctly. I found a few other integrals involving erf() that had similar error in carrying constants through.  >Comment By: Raymond Toy (rtoy) Date: 20051209 21:31 Message: Logged In: YES user_id=28849 Current maxima produces the correct result. Closing bug.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=913239&group_id=4933 