# Composite Kernel Machine Regression based on Likelihood Ratio Test with Application for Combined Genetic and Gene-environment Interaction Effect In CKLRT: Composite Kernel Machine Regression Based on Likelihood Ratio Test

```knitr::opts_chunk\$set(echo = TRUE)
```

# Overview

This vegnette provides an introduction to the 'CKLRT' package. To load the package, users need to install package from CRAN and CKLRT from github. The package can be loaded with the following command:

```#install.packages("devtools")
library(devtools)
#install_github("andrewhaoyu/CKLRT")
library(CKLRT)
```

# Example

In this vegnette, we will decomstrate the methods with a simple example. 1. X present other covariates we want to adjust. 2. E represents the environment variable. 3. G is is the genotype matrix with two SNPs inside 4. y is the simulated outcomes.

```library(mgcv); library(MASS); library(nlme);
library(compiler);library(Rcpp);library(RcppEigen)
library(CKLRT)
set.seed(6)
n = 200 # the number of observations
X = rnorm(n) # the other covariates
p = 2 # two snp in a gene will be simulated
G = runif(n*p)< 0.5
G = G + runif(n*p) < 0.5
G = matrix(G, n,p) #genetic matrix
E = (runif(n) < 0.5)^2 #enviroment effect
y = rnorm(n) + G[,1] * 0.3 #observations
#apply the likelihood ratio test
omniLRT_fast(y, X =  cbind(X, E),K1 = G %*% t(G),K2 = (G*E) %*% t(G * E))
#apply the restricted likelihood ratio test
omniRLRT_fast(y, X =  cbind(X, E),K1 = G %*% t(G),K2 = (G*E) %*% t(G * E))
```

The results of the function contain three elements: 1. p.dir is the p-value of likelihood ratio test based on emprical distrition. 2. p.aud is the p-value by approximating the null distribution as a mixture of a point mass at zero with probability b and weighted chi square distribution with d degrees of freedom with probality of 1-b. 3. LR is the likelihood ratio test statistics.

# References

1. N. Zhao, H. Zhang, J. Clark, A. Maity, M. Wu. Composite Kernel Machine Regression based on Likelihood Ratio Test with Application for Combined Genetic and Gene-environment Interaction Effect (Submitted)

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CKLRT documentation built on May 1, 2019, 10:20 p.m.