result_est_MAP: Posterior inference results from the object of S5

In BayesS5: Bayesian Variable Selection Using Simplified Shotgun Stochastic Search with Screening (S5)

Description

Using the object of S5, the maximum a posteriori (MAP) estimator and Bayesian Model Averaged (BMA) estimators of the regression coefficients are provided.

Usage

result_est_MAP(res,X,y,obj_fun,verbose = TRUE)

Arguments

res	an object of the 'S5' function.
X	the covariates.
y	the response varaible.
obj_fun	the negative log (unnormalized) posterior density when a model is given.
verbose	logical; default is TRUE.

Value

intercept.MAP	the MAP estimator of the intercept.
beta.MAP	the MAP estimator of the regression coefficients.
sig.MAP	the MAP estimator of the regression variance.
intercept.BMA	the Baeysian model averaged estimator of the intercept.
beta.BMA	the Bayesian model averaged estimator of the regression coefficients.

Author(s)

Shin Minsuk and Ruoxuan Tian

References

Shin, M., Bhattacharya, A., Johnson V. E. (2018) A Scalable Bayesian Variable Selection Using Nonlocal Prior Densities in Ultrahigh-dimensional Settings, Statistica Sinica.

Hans, C., Dobra, A., and West, M. (2007). Shotgun stochastic search for large p regression. Journal of the American Statistical Association, 102, 507-516.

Nikooienejad,A., Wang, W., and Johnson V.E. (2016). Bayesian variable selection for binary outcomes in high dimensional genomic studies using non-local priors. Bioinformatics, 32(9), 1338-45.

Examples

p=5000
n = 100

indx.beta = 1:5
xd0 = rep(0,p);xd0[indx.beta]=1
bt0 = rep(0,p); 
bt0[1:5]=c(1,1.25,1.5,1.75,2)*sample(c(1,-1),5,replace=TRUE)
xd=xd0
bt=bt0
X = matrix(rnorm(n*p),n,p)
y = X%*%bt0 + rnorm(n)*sqrt(1.5)
X = scale(X)
y = y-mean(y)
y = as.vector(y)

### piMoM  
#C0 = 2 # the number of repetitions of S5 algorithms to explore the model space
#tuning = 10 # tuning parameter
#tuning = hyper_par(type="pimom",X,y,thre = p^-0.5)
#print(tuning)
#ind_fun = ind_fun_pimom # choose the prior on the regression coefficients (pimom in this case)
#model = Bernoulli_Uniform # choose the model prior 
#tem =  seq(0.4,1,length.out=20)^2 # the sequence of the temperatures

#fit_pimom = S5(X,y,ind_fun=ind_fun,model = model,tuning=tuning,tem=tem,C0=C0)
#fit_pimom$GAM # the searched models by S5
#fit_pimom$OBJ # the corresponding log (unnormalized) posterior probability

#res_pimom = result(fit_pimom)
#est.MAP = result_est_MAP(res_pimom,X,y,obj_fun_pimom,verbose=TRUE)
#plot(est.MAP$beta.MAP,est.MAP$beta.BMA)
#abline(0,1,col="red")

BayesS5 documentation built on March 26, 2020, 7:14 p.m.