# CGGP_internal_CorrMatMatern52: Matern 5/2 correlation function In CollinErickson/CGGP: Composite Grid Gaussian Processes

## Description

Calculate correlation matrix for two sets of points in one dimension. Note that this is not the correlation between two vectors.

## Usage

 ```1 2 3 4 5 6 7 8``` ```CGGP_internal_CorrMatMatern52( x1, x2, theta, return_dCdtheta = FALSE, return_numpara = FALSE, returnlogs = FALSE ) ```

## Arguments

 `x1` Vector of coordinates from same dimension `x2` Vector of coordinates from same dimension `theta` Correlation parameters: LS Log of parameter that controls lengthscale FD Logit of 0.5*parameter that controls the fractal dimension HE Log of parameter that controls the hurst effect `return_dCdtheta` Should dCdtheta be returned? `return_numpara` Should it just return the number of parameters? `returnlogs` Should log of correlation be returned?

## Value

Matrix of correlation values between x1 and x2

Other correlation functions: `CGGP_internal_CorrMatCauchySQT()`, `CGGP_internal_CorrMatCauchySQ()`, `CGGP_internal_CorrMatCauchy()`, `CGGP_internal_CorrMatGaussian()`, `CGGP_internal_CorrMatMatern32()`, `CGGP_internal_CorrMatPowerExp()`, `CGGP_internal_CorrMatWendland0()`, `CGGP_internal_CorrMatWendland1()`, `CGGP_internal_CorrMatWendland2()`
 `1` ```CGGP_internal_CorrMatMatern52(c(0,.2,.4),c(.1,.3,.5), theta=c(-.7)) ```