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Re: derivative function in IDL similar as DIFF in matlab [message #86462 is a reply to message #86461]

Tue, 12 November 2013 02:27

lecacheux.alain
Messages: 325
Registered: January 2008

Senior Member

Le mardi 12 novembre 2013 11:08:11 UTC+1, Jie Zhou a écrit :
> Is there a derivative function in IDL similar as DIFF in matlab? I think the DERIV is different from DIFF.

The DERIV function in IDL uses a second order formula for the discrete differenciation (known as 3-point Lagrange interpolation). Afaik, Matlab DIFF computes a simple difference given, in IDL, by x - shift(x,1), where x is your data series.
alx.

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[Message index]

		derivative function in IDL similar as DIFF in matlab By: Jie Zhou on Tue, 12 November 2013 02:08
		Re: derivative function in IDL similar as DIFF in matlab By: lecacheux.alain on Tue, 12 November 2013 02:27
		Re: derivative function in IDL similar as DIFF in matlab By: Matthew Argall on Tue, 12 November 2013 04:01
		Re: derivative function in IDL similar as DIFF in matlab By: lecacheux.alain on Tue, 12 November 2013 04:07
		Re: derivative function in IDL similar as DIFF in matlab By: Matthew Argall on Tue, 12 November 2013 04:08
		Re: derivative function in IDL similar as DIFF in matlab By: Jie Zhou on Tue, 12 November 2013 04:18
		Re: derivative function in IDL similar as DIFF in matlab By: Matthew Argall on Tue, 12 November 2013 06:07

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