Y: The data matrix. Rows are observations and columns are features (e.g. genes). If not specified, Y.svd must be specified instead (which is faster).
Z: Any variables to regress out of Y as a preprocessing step. May simply be 1 (the default) for an intercept term, i.e. the columns of Y are mean centered. May also be NULL.
Y.svd: The SVD of Y, as returned by the svd function.
Details
Because 0 cannot be plotted on a log scale, if any singular values are equal to 0, they will be changed to the minimum non-zero singular value and plotted in red. Exception: singular values that are 0 as a result of regressing out Z are simply not plotted.