Functions:
=========
bpca.default      Biplot for `data.frame' or `matrix' objects.
bpca.prcomp       Biplot for `prcomp' objects.
bppca             Main function (S3 based).
plot.bpca.2d      Plots `bpca.2d' objects with the package `graphics'.
plot.bpca.3d      Plots `bpca.3d' objects with the packages `scatterplot3d'
                  (`graphics' based) and `rgl' (OpenGL based).
plot.qbpca        Plots `qbpca' objects with the package `graphics'.
qbpca             Evaluates the quality of the biplot representation for
                  `bpca.2d' and `bpca.3d' objects.
summary.bpca      Summarizes `bpca' (`bpca.2d' and `bpca.3d') objects.
var.rbf           Calculates the matrix of graphical correlations projected by
                  the biplot for `bpca.2d' and `bpca.3d' objects.
var.rdf           Calculates the matrix of `poor' graphical correlations,
                  represented by the biplot, for `bpca.2d' and `bpca_3d'
                  objects.
dt.tools          Calculates vector variable lengths, angles between vector
                  variables and variable correlations from `data.frame' or
                  `matrix' objects.

Datasets:
========
gabriel1971       Percentages of households having various facilities and
                  appliances in East Jerusalem Arab areas, by quarters of
                  the town.
gge2003           A didatic matrix of genotypes (rows) and environments
                  (columns).
