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OpenDendro / dplR

This is the dev site for the dplR package in R
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Gleichläufigkeit #10

Closed Mono2 closed 2 years ago

Mono2 commented 2 years ago

Hi, first of all, I really enjoy dplR. Thank you for all the work you have put into this package!

I have a question regarding the calculation of Glk in dplR: if one series lacks growth change from one year to the other, while the other series does not, you calculate a "1" for that year. But shouldn't it be a "2"?

Let's take an example of two five-year long series, which feature growth changes (sign()) as follows:

series 1 series 2 series 1 - series 2
-1 -1 0
-1 1 2
-1 0 1
1 1 0
colSum: 3

Your Glk-value would be 1-(3/(2*4) = 0.625 Maybe I am mistaken, but I would think Glk should be 0.5, because only the first and last year feature similar growth change.

In case I am wrong, I excuse for the issue...

All the best, Manuel

Mono2 commented 2 years ago

Well I now did find the SGC (Synchronous Growth Changes) by @RonaldVisser....