[ https://issues.apache.org/jira/browse/MATH-596?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Luc Maisonobe resolved MATH-596. -------------------------------- Resolution: Fixed Fixed in subversion repository as of r1139831. Thanks for the report > GraggBulirschStoerIntegrator output too low > ------------------------------------------- > > Key: MATH-596 > URL: https://issues.apache.org/jira/browse/MATH-596 > Project: Commons Math > Issue Type: Bug > Affects Versions: 3.0 > Reporter: Dennis Hendriks > Attachments: MyTest.java, MyTest2.java > > > I have the following problem: > x(3.0) = 4.0 > x' = 3.0 > t0 = 3.0 > tend = 10.0 > ODE solving using the GraggBulirschStoerIntegrator(1e-10, 100.0, 1e-7, 1e-7) > integrator, gives me: > t, x, x' > 3.0, 4.0, 3.0 > 3.105840007284127, 4.0, 3.0 > 3.829973288493221, 4.31752002185238, 3.0 > 8.784328663271161, 6.489919865479664, 3.0 > 10.0, 21.35298598981348, 3.0 > Clearly, the value of x at time 3.10... should be something like 4.30... and > not 4.0. Also, the value of x at time 10.0 should be around 25.0 and not be > 21.35... > If we switch to the DormandPrince853Integrator(1e-10, 100.0, 1e-7, 1e-7), it > gives me: > 3.0, 4.0, 3.0 > 3.079933916721644, 4.239801750164932, 3.0 > 3.8792730839380845, 6.637819251814253, 3.0 > 10.0, 24.999999999999996, 3.0 > as expected. > This seems to me like the GraggBulirschStoerIntegrator has a bug... -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira