corrected_cs_bhat {corrcoverage} | R Documentation |
Corrected credible set using estimated effect sizes and their standard errors
Description
Corrected credible set using estimated effect sizes and their standard errors
Usage
corrected_cs_bhat(
bhat,
V,
N0,
N1,
Sigma,
W = 0.2,
lower = 0,
upper = 1,
desired.cov,
acc = 0.005,
max.iter = 20,
pp0min = 0.001
)
Arguments
bhat |
Estimated effect sizes |
V |
Prior variance of estimated effect sizes |
N0 |
Number of controls |
N1 |
Number of cases |
Sigma |
Correlation matrix of SNPs |
W |
Prior for the standard deviation of the effect size parameter, beta (default 0.2) |
lower |
Lower threshold (default = 0) |
upper |
Upper threshold (default = 1) |
desired.cov |
The desired coverage of the causal variant in the credible set |
acc |
Accuracy of corrected coverage to desired coverage (default = 0.005) |
max.iter |
Maximum iterations (default = 20) |
pp0min |
Only average over SNPs with pp0 > pp0min |
Value
List of variants in credible set, required threshold, the corrected coverage and the size of the credible set
Author(s)
Anna Hutchinson
Examples
# this is a long running example
# In this example, the function is used to find a corrected 95% credible set
# using bhats and their standard errors, that is the smallest set of variants
# required such that the resultant credible set has coverage close to (/within
# some accuracy of) the "desired coverage" (here set to 0.95). Max.iter parameter
# defines the maximum number of iterations to try in the root bisection algorithm,
# this should be increased to ensure convergence to the desired coverage, but is set
# to 1 here for speed (and thus the resultant credible set will not be accurate).
set.seed(18)
nsnps <- 100
N0 <- 500 # number of controls
N1 <- 500 # number of cases
# simulate fake haplotypes to obtain MAFs and LD matrix
## generate example LD matrix
library(mvtnorm)
nsamples = 1000
simx <- function(nsnps, nsamples, S, maf=0.1) {
mu <- rep(0,nsnps)
rawvars <- rmvnorm(n=nsamples, mean=mu, sigma=S)
pvars <- pnorm(rawvars)
x <- qbinom(1-pvars, 1, maf)
}
S <- (1 - (abs(outer(1:nsnps,1:nsnps,`-`))/nsnps))^4
X <- simx(nsnps,nsamples,S)
LD <- cor2(X)
maf <- colMeans(X)
varbeta <- Var.data.cc(f = maf, N = N0 + N1, s = N1/(N0+N1))
bhats = rnorm(nsnps,0,0.2) # log OR
names(bhats) <- seq(1,length(bhats))
corrected_cs_bhat(bhat = bhats, V = varbeta, N0, N1, Sigma = LD, desired.cov = 0.9, max.iter = 1)
# max.iter set low for speed, should be set to at
# least the default to ensure convergence to desired coverage
[Package corrcoverage version 1.2.1 Index]