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Re: Check numerical derivatives [message #94535 is a reply to message #94534]

Wed, 28 June 2017 07:46

wlandsman
Messages: 743
Registered: June 2000

Senior Member

On Wednesday, June 28, 2017 at 4:23:45 AM UTC-4, geo...@gmail.com wrote:

> Your comment 2 was interesting. Is any other way to make it calculate the derivatives of all columns tho?

Well, you can't take the left-sided derivative of the first column because there is no column to the left. But it might be useful to keep the derivative array the same size as the original array. One could use the right-sided derivative for the first column, which would be the same as the left-sided derivative of the second column. --Wayne

F_x = F[1:nx-1,*]-F[0:nx-2,*]
F_x = [F_x[0,*],F_x]

(Of course the three point Lagrangian interpolation of the DERIV() function would be preferable.)

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[Message index]

		Check numerical derivatives By: geo85c on Tue, 27 June 2017 03:30
		Re: Check numerical derivatives By: wlandsman on Tue, 27 June 2017 07:52
		Re: Check numerical derivatives By: geo85c on Wed, 28 June 2017 01:23
		Re: Check numerical derivatives By: wlandsman on Wed, 28 June 2017 07:46

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