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From: SourceForge.net <noreply@so...>  20090108 16:17:46

Bugs item #2494112, was opened at 20090108 17:17 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=2494112&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  Plotting Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Fabrizio Berloco (fabri_berloco) Assigned to: Nobody/Anonymous (nobody) Summary: Clotoid (Cornu's Spiral) is not plotted Initial Comment: I'm trying to plot a Cornu's Spiral that is given by a parametric plot of Fresnel Integrals, but I get a very wrong graph; I tried also plotting the same function on Mathematica and I got the right graph; this is maxima (wxMaxima 0.7.1 GNU Linux Debian) code: x(t)=integrate(cos(2*(t^2)/%pi),t)/sqrt(2/%pi); y(t)=integrate(sin(2*(t^2)/%pi),t)/sqrt(2/%pi); plot2d([parametric,x(t),y(t),[t,7,7]]); Mathematica (Linux Version) code is: ParametricPlot[{FresnelC[Sqrt[2/Pi]*t]/Sqrt[2/Pi], FresnelS[Sqrt[2/Pi]*t]/Sqrt[2/Pi]}, {t, 7, 7}] With this last I get the right spiral (see also: "http://wapedia.mobi/en/Image:Cornu_Spiral.svg";)  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2494112&group_id=4933 
From: SourceForge.net <noreply@so...>  20090110 17:48:02

Bugs item #2494112, was opened at 20090108 17:17 Message generated for change (Comment added) made by crategus You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2494112&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  Plotting Group: None >Status: Pending >Resolution: Works For Me Priority: 5 Private: No Submitted By: Fabrizio Berloco (fabri_berloco) Assigned to: Nobody/Anonymous (nobody) Summary: Clotoid (Cornu's Spiral) is not plotted Initial Comment: I'm trying to plot a Cornu's Spiral that is given by a parametric plot of Fresnel Integrals, but I get a very wrong graph; I tried also plotting the same function on Mathematica and I got the right graph; this is maxima (wxMaxima 0.7.1 GNU Linux Debian) code: x(t)=integrate(cos(2*(t^2)/%pi),t)/sqrt(2/%pi); y(t)=integrate(sin(2*(t^2)/%pi),t)/sqrt(2/%pi); plot2d([parametric,x(t),y(t),[t,7,7]]); Mathematica (Linux Version) code is: ParametricPlot[{FresnelC[Sqrt[2/Pi]*t]/Sqrt[2/Pi], FresnelS[Sqrt[2/Pi]*t]/Sqrt[2/Pi]}, {t, 7, 7}] With this last I get the right spiral (see also: "http://wapedia.mobi/en/Image:Cornu_Spiral.svg";)  >Comment By: Dieter Kaiser (crategus) Date: 20090110 18:48 Message: At first, I think, the problem is not well formulated. The Fresnel functions have to be given as a definite integral e.g. C(t) := integrate(cos(%pi*x^2/2),x,0,t) This could be the definitions to do the numerical evaluation (example taken from the mailing list): (%i5) assume(t>0)$ (%i6) x(t):=realpart(float(''integrate(cos(%pi*x^2/2),x,0,t)))$ (%i7) y(t):=realpart(float(''integrate(sin(%pi*x^2/2),x,0,t)))$ The following plot will work with Maxima 5.17post (in Maxima 5.17 we have a bug in the numerical evaluation of the Error function for imaginary arguments): (%i8) plot2d([parametric,x(t),y(t),[t,7,7]],[nticks,300]); Because the Fresnel Integrals are implemented in Maxima 5.17post this works too: (%i9) plot2d([parametric,fresnel_c(t),fresnel_s(t),[t,7,7]],[nticks,300]); The numerical evaluation of the integrals need the evaluation of the Error function for complex arguments. This is not implemented in earlier versions of Maxima. An alternative is to do the numerical evaluation of the integrals with the package quadpack. The plot works with Maxima 5.17post. Setting this bug report to pending. Dieter Kaiser  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2494112&group_id=4933 
From: SourceForge.net <noreply@so...>  20090318 18:50:03

Bugs item #2494112, was opened at 20090108 16:17 Message generated for change (Comment added) made by sfrobot You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2494112&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  Plotting Group: None >Status: Closed Resolution: Works For Me Priority: 5 Private: No Submitted By: Fabrizio Berloco (fabri_berloco) Assigned to: Nobody/Anonymous (nobody) Summary: Clotoid (Cornu's Spiral) is not plotted Initial Comment: I'm trying to plot a Cornu's Spiral that is given by a parametric plot of Fresnel Integrals, but I get a very wrong graph; I tried also plotting the same function on Mathematica and I got the right graph; this is maxima (wxMaxima 0.7.1 GNU Linux Debian) code: x(t)=integrate(cos(2*(t^2)/%pi),t)/sqrt(2/%pi); y(t)=integrate(sin(2*(t^2)/%pi),t)/sqrt(2/%pi); plot2d([parametric,x(t),y(t),[t,7,7]]); Mathematica (Linux Version) code is: ParametricPlot[{FresnelC[Sqrt[2/Pi]*t]/Sqrt[2/Pi], FresnelS[Sqrt[2/Pi]*t]/Sqrt[2/Pi]}, {t, 7, 7}] With this last I get the right spiral (see also: "http://wapedia.mobi/en/Image:Cornu_Spiral.svg";)  >Comment By: SourceForge Robot (sfrobot) Date: 20090318 18:49 Message: This Tracker item was closed automatically by the system. It was previously set to a Pending status, and the original submitter did not respond within 14 days (the time period specified by the administrator of this Tracker).  Comment By: Dieter Kaiser (crategus) Date: 20090110 17:48 Message: At first, I think, the problem is not well formulated. The Fresnel functions have to be given as a definite integral e.g. C(t) := integrate(cos(%pi*x^2/2),x,0,t) This could be the definitions to do the numerical evaluation (example taken from the mailing list): (%i5) assume(t>0)$ (%i6) x(t):=realpart(float(''integrate(cos(%pi*x^2/2),x,0,t)))$ (%i7) y(t):=realpart(float(''integrate(sin(%pi*x^2/2),x,0,t)))$ The following plot will work with Maxima 5.17post (in Maxima 5.17 we have a bug in the numerical evaluation of the Error function for imaginary arguments): (%i8) plot2d([parametric,x(t),y(t),[t,7,7]],[nticks,300]); Because the Fresnel Integrals are implemented in Maxima 5.17post this works too: (%i9) plot2d([parametric,fresnel_c(t),fresnel_s(t),[t,7,7]],[nticks,300]); The numerical evaluation of the integrals need the evaluation of the Error function for complex arguments. This is not implemented in earlier versions of Maxima. An alternative is to do the numerical evaluation of the integrals with the package quadpack. The plot works with Maxima 5.17post. Setting this bug report to pending. Dieter Kaiser  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2494112&group_id=4933 