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From: | Andreas Stahel |
Subject: | [Octave-bug-tracker] [bug #50012] ode23 internal interpolation |
Date: | Tue, 10 Jan 2017 09:38:05 +0000 (UTC) |
User-agent: | Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:50.0) Gecko/20100101 Firefox/50.0 |
URL: <http://savannah.gnu.org/bugs/?50012> Summary: ode23 internal interpolation Project: GNU Octave Submitted by: sha1 Submitted on: Tue 10 Jan 2017 10:38:04 AM CET Category: Octave Function Severity: 3 - Normal Priority: 5 - Normal Item Group: Inaccurate Result Status: None Assigned to: None Originator Name: Originator Email: Open/Closed: Open Discussion Lock: Any Release: dev Operating System: Any _______________________________________________________ Details: Recently I ran across a possible problem in the integration/interpolation of the ode23 solver. Examine the result of the enclosed script. The problem shows when working with the derivative of a solution and is most likely caused by the interpolation to the values given in tspan. When I change line 157 in the function integrate_adaptive order --> order+1 or order --> order-1 the results look smooth. Thus I suspect a minor problem with the piecewise interpolation of the order used by ode23. The problems show in version 4.2.0 and the development branch. The version of ode23 in odepkg does not display the problem. With best regards Andreas Stahel _______________________________________________________ File Attachments: ------------------------------------------------------- Date: Tue 10 Jan 2017 10:38:04 AM CET Name: Test_ode23.m Size: 838B By: sha1 <http://savannah.gnu.org/bugs/download.php?file_id=39422> ------------------------------------------------------- Date: Tue 10 Jan 2017 10:38:04 AM CET Name: Test_ode23.png Size: 29kB By: sha1 <http://savannah.gnu.org/bugs/download.php?file_id=39423> _______________________________________________________ Reply to this item at: <http://savannah.gnu.org/bugs/?50012> _______________________________________________ Message sent via/by Savannah http://savannah.gnu.org/
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