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Student Support Forum: 'How do I choose precision & accuracy in NDSolve?' topicStudent Support Forum > General > "How do I choose precision & accuracy in NDSolve?"

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snackman
07/21/10 04:51am

How do I choose the right Precision and/or Accuracy in NDSolve so that I don't get the following errors?

sol2 = NDSolve[{15*theta''[s] ==
N3[s] Cos[theta[s]] - N1[s] Sin[theta[s]],
N1'[s] == 0, N3'[s] == 0,
x'[s] == Cos[theta[s]],
z'[s] == Sin[theta[s]],
x[0] == 0, x[1.5] == 1,
z[0] == 0, z[1.5] == 0,
theta[0] == 0, theta[1.5] == 0}, {theta, x, z, N1, N3}, {s, 0, 1.5}];

FindRoot::sszero: The step size in the search has become less than the tolerance prescribed by the PrecisionGoal option, but the function value is still greater than the tolerance prescribed by the AccuracyGoal option. >>

NDSolve::berr: There are significant errors {-0.25,0.25,-<<24>>,<<21>>,-<<23>>,-1.27536*10^-16} in the boundary value residuals. Returning the best solution found. >>

A solution for this paticular problem would be helpful, and adaptive way to make it work for a range of boundary conditions would be even better. Thanks in advance!

Attachment: problem.nb, URL: ,

Subject (listing for 'How do I choose precision & accuracy in NDSolve?')
Author Date Posted
How do I choose precision & accuracy in NDSolve? snackman 07/21/10 04:51am
Re: How do I choose precision & accuracy in NDS... yehuda ben-s... 07/25/10 02:57am
Re: Re: How do I choose precision & accuracy in... snackman 07/26/10 02:10am
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