WIPF                    Weighted Iterative Proportional Fitting (WIPF)
                        in N (greater than 1) dimensions
WIPF1                   Weighted Iterative Proportional Fitting (WIPF)
                        in one dimension
WIPF2                   Weighted Iterative Proportional Fitting (WIPF)
                        in two dimensions
WIPF3                   Weighted Iterative Proportional Fitting (WIPF)
                        in three dimensions
array2df                Array to long-format data frame
df2array                Long-format data frame to array
