PCA biplot helper

Combines principal component scores and variable loadings in a single scatter plot. The helper accepts both standard matrices and bigmemory::big.matrix inputs, extracting only the requested component columns. When draw = TRUE, the function scales the loadings to match the score ranges, draws optional axes, overlays loading arrows, and labels observations when requested.

Usage

pca_plot_biplot(
  scores,
  loadings,
  components = c(1L, 2L),
  draw = TRUE,
  draw_axes = TRUE,
  draw_arrows = TRUE,
  label_points = FALSE,
  ...
)

Arguments

scores

Matrix or bigmemory::big.matrix containing principal component scores with observations in rows and components in columns.

loadings

Matrix or bigmemory::big.matrix of variable loadings whose columns correspond to principal components.

components

Integer vector of length two selecting the components to display.

draw

Logical; set to FALSE to return the prepared data without plotting.

draw_axes

Logical; when TRUE, horizontal and vertical axes are drawn through the origin.

draw_arrows

Logical; when TRUE, loading arrows are rendered.

label_points

Logical; when TRUE, point labels derived from row names are drawn next to the scores.

...

Additional graphical parameters passed to graphics::plot().

Value

A list containing the selected components, extracted scores, original loadings, scaled loadings (loadings_scaled), and the applied scale_factor. The list is returned invisibly. When draw = TRUE, a biplot is produced using base graphics.