# derivcormatrix: First and second derivates of some correlation matrix In CensSpatial: Censored Spatial Models

## Description

It computes the matrix of first and second derivates for the exponential, gaussian, matern, spherical, powered exponential and Cauchy correlation matrix.

## Usage

 `1` ```derivcormatrix(coords, phi, kappa = 0, cov.model = "exponential") ```

## Arguments

 `coords` 2D spatial coordinates. `phi` parameter for the matern, powered exponential and cauchy functions. `kappa` parameter for all correlation functions. `cov.model` parameter correlation funtion to calculates the derivates in this case 6 functions are avalible "exponential", "gaussian", "matern", "spherical", "powered.exponential", "cauchy".

## Details

The correlations functions used to calculate the derivates from this 6 functions are based in the functions by the package `geoR` (see `cov.spatial`).

## Value

 `H` distance matrix. `devR1` first derivate of the correlation matrix. `devR2` second derivate of the correlation matrix.

## Author(s)

Alejandro Ordonez <<ordonezjosealejandro@gmail.com>>, Victor H. Lachos <<hlachos@ime.unicamp.br>> and Christian E. Galarza <<cgalarza88@gmail.com>>

Maintainer: Alejandro Ordonez <<ordonezjosealejandro@gmail.com>>

## References

Diggle, P. & Ribeiro, P. (2007). Model-Based Geostatistics. Springer Series in Statistics.

Gradshtejn, I. S. & Ryzhik, I. M. (1965). Table of integrals, series and products. Academic Press.

`SAEMSCL`
 ```1 2 3 4 5 6 7``` ```n<-200 n1=100 r1=sample(seq(1,30,length=400),n+n1) r2=sample(seq(1,30,length=400),n+n1) coords=cbind(r1,r2) s=derivcormatrix(coords=coords,phi=2,kappa=2,cov.model="exponential") ```