This is a function that takes in two matrices of dimension nxB and nxk and returns a Bxk matrix that comes from element-wise multiplication of every column in the first matrix times the entire second matrix and the averaging over the n-dimension. It is equivalent (but faster than) the following R code: `sapply(1:biters, function(b) sqrt(n)*colMeans(Umat[,b]*inf.func))` . This function is particularly useful for fast computations using the multiplier bootstrap.
element_wise_mult(U, inf_func)nxB matrix (e.g., these could be a matrix of Rademachar weights for B bootstrap iterations using the multiplier bootstrap
nxk matrix of (e.g., these could be a matrix containing the influence function for different parameter estimates)
a Bxk matrix