fix the value of nugget
On 09/09/2015 01:09 PM, Sherien Al-Azerji wrote:
Dear All, I'm running Universal kriking method and I need to set the value of nugget in the variogram model to zero even after fitting a variogram, I need the fitted variogram to have a zero nugget. How can I do this please.
Showing what you've tried would help. Assuming you use package gstat, you can pass a variogram model without nugget (e.g. vgm(1, "Exp", 300) ) to fit.variogram, and no (=zero) nugget will be fitted.
another question please, some times when I run my code I get this error message (LDL factor) what this mean? and how can I solve it.
It means the covariance matrix is (too close to) singular; this happens if you have (nearly) duplicate observations, or a variogram model that gives rise to (nearly) perfectly correlated observations, such as the Gaussian model.
Best Regards Sherien [[alternative HTML version deleted]]
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