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Nonlinear derivative in finite difference

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Old   February 23, 2021, 09:24
Default Nonlinear derivative in finite difference
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How to write this in finite difference?

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Old   February 23, 2021, 10:24
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first decide which finite difference you need for d/dx. stencil size - number of nodes - one sided or central. then plug in for inner derivative and apply. then plug in for outer derivative and apply. alternative is: work out full terms first, then apply. what is the purpose of this?
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Old   February 23, 2021, 13:49
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Quote:
Originally Posted by BoxQwerty View Post
How to write this in finite difference?

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If you want to use the divergence form you simply write


0.5*(f(i+1)**3-f(i-1)**3)/h


where f is a vector where you previously computed the discrete derivative du/dx.


Conversely you can expand the derivative in a quasi-linear form.
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