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Re: Equivalent of EXCEL LINEST function? [message #24781 is a reply to message #24775]

Fri, 20 April 2001 17:30

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

Bruce Bowler <bbowler@bigelow.org> writes:
> So it is... now for "stupid question #347" (tm).
>
> How do I turn a vector (which is what I have for x) into an array?
>
> help, x
> x float = array[12345]
> help, y
> y float = array[12345]
> weight = replicate(1.0,n_elements(y))
> help, weight
> weight float = array[12345]
> result = regress(x,y,weight,/relative_weight)
> % REGRESS: Incompatable arrays.
>
> Looking at the code for regress, the only condition I violate to cause
> that message is that my X is only 1 dimenesion, not 2...

Probably you want to REFORM the vector into an array ( = reform(x,1,n))

However using REGRESS may be like killing a fly with a shotgun, a bit
of overkill.

Why not use LINFIT and CORRELATE, which standard IDL functions?

p = linfit(x,y, sigma=dp) ;; DP are parameter uncertainties
r2 = correlate(x,y)

Done!

Craig

--
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Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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[Message index]

		Re: Equivalent of EXCEL LINEST function? By: Bruce Bowler on Mon, 23 April 2001 13:09
		Re: Equivalent of EXCEL LINEST function? By: Craig Markwardt on Fri, 20 April 2001 17:30
		Re: Equivalent of EXCEL LINEST function? By: Bruce Bowler on Fri, 20 April 2001 11:05
		Re: Equivalent of EXCEL LINEST function? By: Med Bennett on Thu, 19 April 2001 12:16
		Re: Equivalent of EXCEL LINEST function? By: Craig Markwardt on Mon, 23 April 2001 13:46

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