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From: SourceForge.net <noreply@so...>  20080513 19:35:43

Bugs item #1963314, was opened at 20080513 12:35 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=1963314&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  Integration Group: None Status: Open Resolution: None Priority: 5 Private: Yes Submitted By: Nobody/Anonymous (nobody) Assigned to: Nobody/Anonymous (nobody) Summary: Fresnel integral  function romberg error. Initial Comment: Maxima 5.14.0 Linux and 5.15.0 Windows. Fresnel integral: http://en.wikipedia.org/wiki/Fresnel_integral http://upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Fresnel_Integrals_%28Normalised%29.svg/250pxFresnel_Integrals_%28Normalised%29.svg.png Maxima command: for i:1 thru 10 do display(romberg(sin(%pi/2*(x^2)),x,0,i)); .... romberg(sin((%pi*x^2)/2),x,0,7)=0.49970480390049 romberg(sin((%pi*x^2)/2),x,0,8)=1.0449974219284286*10^14 romberg(sin((%pi*x^2)/2),x,0,9)=0.49986104588168 also romberg(cos((%pi*x^2)/2),x,0,7)=0.54546705790348 romberg(cos((%pi*x^2)/2),x,0,8)=8.0 romberg(cos((%pi*x^2)/2),x,0,9)=0.53536612585252 in point x=8 is error. Thx  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1963314&group_id=4933 
From: SourceForge.net <noreply@so...>  20080514 00:30:39

Bugs item #1963314, was opened at 20080513 13:35 Message generated for change (Comment added) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1963314&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: Share Libraries Group: None >Status: Pending >Resolution: Wont Fix Priority: 5 Private: Yes Submitted By: Nobody/Anonymous (nobody) Assigned to: Nobody/Anonymous (nobody) Summary: Fresnel integral  function romberg error. Initial Comment: Maxima 5.14.0 Linux and 5.15.0 Windows. Fresnel integral: http://en.wikipedia.org/wiki/Fresnel_integral http://upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Fresnel_Integrals_%28Normalised%29.svg/250pxFresnel_Integrals_%28Normalised%29.svg.png Maxima command: for i:1 thru 10 do display(romberg(sin(%pi/2*(x^2)),x,0,i)); .... romberg(sin((%pi*x^2)/2),x,0,7)=0.49970480390049 romberg(sin((%pi*x^2)/2),x,0,8)=1.0449974219284286*10^14 romberg(sin((%pi*x^2)/2),x,0,9)=0.49986104588168 also romberg(cos((%pi*x^2)/2),x,0,7)=0.54546705790348 romberg(cos((%pi*x^2)/2),x,0,8)=8.0 romberg(cos((%pi*x^2)/2),x,0,9)=0.53536612585252 in point x=8 is error. Thx  >Comment By: Robert Dodier (robert_dodier) Date: 20080513 18:30 Message: Logged In: YES user_id=501686 Originator: NO romberg is easily fooled by oscillatory integrands: it evaluates the integrand at a few points and sees that they are the same, so it thinks the integrand is constant. Much better to use the Quadpack functions, namely quad_qags, etc. ?? quad at the input prompt should find them. You can fiddle with some parameters to make romberg succeed on this problem (?? romberg finds them), but romberg is just not a very strong algorithm; use quad_qags or some other Quadpack function instead. Marking this report as "won't fix"; the romberg function is a correct implementation of Romberg's method. Instead of closing it, I'll leave it pending, so it stays open for a while in case the original poster comes back. Note: please log in so that annotations on bug reports are automatically sent to you.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1963314&group_id=4933 
From: SourceForge.net <noreply@so...>  20080514 00:31:39

Bugs item #1963314, was opened at 20080513 13:35 Message generated for change (Settings changed) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1963314&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: Share Libraries Group: None Status: Pending Resolution: Wont Fix Priority: 5 >Private: No Submitted By: Nobody/Anonymous (nobody) Assigned to: Nobody/Anonymous (nobody) Summary: Fresnel integral  function romberg error. Initial Comment: Maxima 5.14.0 Linux and 5.15.0 Windows. Fresnel integral: http://en.wikipedia.org/wiki/Fresnel_integral http://upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Fresnel_Integrals_%28Normalised%29.svg/250pxFresnel_Integrals_%28Normalised%29.svg.png Maxima command: for i:1 thru 10 do display(romberg(sin(%pi/2*(x^2)),x,0,i)); .... romberg(sin((%pi*x^2)/2),x,0,7)=0.49970480390049 romberg(sin((%pi*x^2)/2),x,0,8)=1.0449974219284286*10^14 romberg(sin((%pi*x^2)/2),x,0,9)=0.49986104588168 also romberg(cos((%pi*x^2)/2),x,0,7)=0.54546705790348 romberg(cos((%pi*x^2)/2),x,0,8)=8.0 romberg(cos((%pi*x^2)/2),x,0,9)=0.53536612585252 in point x=8 is error. Thx  Comment By: Robert Dodier (robert_dodier) Date: 20080513 18:30 Message: Logged In: YES user_id=501686 Originator: NO romberg is easily fooled by oscillatory integrands: it evaluates the integrand at a few points and sees that they are the same, so it thinks the integrand is constant. Much better to use the Quadpack functions, namely quad_qags, etc. ?? quad at the input prompt should find them. You can fiddle with some parameters to make romberg succeed on this problem (?? romberg finds them), but romberg is just not a very strong algorithm; use quad_qags or some other Quadpack function instead. Marking this report as "won't fix"; the romberg function is a correct implementation of Romberg's method. Instead of closing it, I'll leave it pending, so it stays open for a while in case the original poster comes back. Note: please log in so that annotations on bug reports are automatically sent to you.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1963314&group_id=4933 
From: SourceForge.net <noreply@so...>  20080514 00:32:49

Bugs item #1963314, was opened at 20080513 13:35 Message generated for change (Comment added) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1963314&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: Share Libraries Group: None >Status: Open Resolution: Wont Fix Priority: 5 Private: No Submitted By: Nobody/Anonymous (nobody) Assigned to: Nobody/Anonymous (nobody) Summary: Fresnel integral  function romberg error. Initial Comment: Maxima 5.14.0 Linux and 5.15.0 Windows. Fresnel integral: http://en.wikipedia.org/wiki/Fresnel_integral http://upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Fresnel_Integrals_%28Normalised%29.svg/250pxFresnel_Integrals_%28Normalised%29.svg.png Maxima command: for i:1 thru 10 do display(romberg(sin(%pi/2*(x^2)),x,0,i)); .... romberg(sin((%pi*x^2)/2),x,0,7)=0.49970480390049 romberg(sin((%pi*x^2)/2),x,0,8)=1.0449974219284286*10^14 romberg(sin((%pi*x^2)/2),x,0,9)=0.49986104588168 also romberg(cos((%pi*x^2)/2),x,0,7)=0.54546705790348 romberg(cos((%pi*x^2)/2),x,0,8)=8.0 romberg(cos((%pi*x^2)/2),x,0,9)=0.53536612585252 in point x=8 is error. Thx  >Comment By: Robert Dodier (robert_dodier) Date: 20080513 18:32 Message: Logged In: YES user_id=501686 Originator: NO Changing status back to open so it appears in the default browsing mode.  Comment By: Robert Dodier (robert_dodier) Date: 20080513 18:30 Message: Logged In: YES user_id=501686 Originator: NO romberg is easily fooled by oscillatory integrands: it evaluates the integrand at a few points and sees that they are the same, so it thinks the integrand is constant. Much better to use the Quadpack functions, namely quad_qags, etc. ?? quad at the input prompt should find them. You can fiddle with some parameters to make romberg succeed on this problem (?? romberg finds them), but romberg is just not a very strong algorithm; use quad_qags or some other Quadpack function instead. Marking this report as "won't fix"; the romberg function is a correct implementation of Romberg's method. Instead of closing it, I'll leave it pending, so it stays open for a while in case the original poster comes back. Note: please log in so that annotations on bug reports are automatically sent to you.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1963314&group_id=4933 
From: SourceForge.net <noreply@so...>  20080603 03:58:47

Bugs item #1963314, was opened at 20080513 13:35 Message generated for change (Comment added) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1963314&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: Share Libraries Group: None >Status: Closed Resolution: Wont Fix Priority: 5 Private: No Submitted By: Nobody/Anonymous (nobody) Assigned to: Nobody/Anonymous (nobody) Summary: Fresnel integral  function romberg error. Initial Comment: Maxima 5.14.0 Linux and 5.15.0 Windows. Fresnel integral: http://en.wikipedia.org/wiki/Fresnel_integral http://upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Fresnel_Integrals_%28Normalised%29.svg/250pxFresnel_Integrals_%28Normalised%29.svg.png Maxima command: for i:1 thru 10 do display(romberg(sin(%pi/2*(x^2)),x,0,i)); .... romberg(sin((%pi*x^2)/2),x,0,7)=0.49970480390049 romberg(sin((%pi*x^2)/2),x,0,8)=1.0449974219284286*10^14 romberg(sin((%pi*x^2)/2),x,0,9)=0.49986104588168 also romberg(cos((%pi*x^2)/2),x,0,7)=0.54546705790348 romberg(cos((%pi*x^2)/2),x,0,8)=8.0 romberg(cos((%pi*x^2)/2),x,0,9)=0.53536612585252 in point x=8 is error. Thx  >Comment By: Robert Dodier (robert_dodier) Date: 20080602 21:58 Message: Logged In: YES user_id=501686 Originator: NO Closing this report as "won't fix" per earlier comment.  Comment By: Robert Dodier (robert_dodier) Date: 20080513 18:32 Message: Logged In: YES user_id=501686 Originator: NO Changing status back to open so it appears in the default browsing mode.  Comment By: Robert Dodier (robert_dodier) Date: 20080513 18:30 Message: Logged In: YES user_id=501686 Originator: NO romberg is easily fooled by oscillatory integrands: it evaluates the integrand at a few points and sees that they are the same, so it thinks the integrand is constant. Much better to use the Quadpack functions, namely quad_qags, etc. ?? quad at the input prompt should find them. You can fiddle with some parameters to make romberg succeed on this problem (?? romberg finds them), but romberg is just not a very strong algorithm; use quad_qags or some other Quadpack function instead. Marking this report as "won't fix"; the romberg function is a correct implementation of Romberg's method. Instead of closing it, I'll leave it pending, so it stays open for a while in case the original poster comes back. Note: please log in so that annotations on bug reports are automatically sent to you.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=1963314&group_id=4933 
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