normalize_gram: Normalization of the Gram matrix
In conmolfields: Continuous molecular fields

Normalization of the Gram matrix

1	normalize_gram(gram)

gram

##---- Should be DIRECTLY executable !! ----
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as

function(gram) {
  ndim <- dim(gram)[1]
  for (irow in 1:(ndim-1)) {
    for (icol in (irow+1):ndim) {
      gram[irow,icol] <- gram[irow,icol] / (sqrt(gram[irow,irow]) * sqrt(gram[icol,icol]))
      gram[icol,irow] <- gram[irow,icol]
    }
  }
  for (i in 1:ndim) {
    gram[i,i] <- 1.0
  }
  gram
}