Warn about columns standardization cannot scale

Names the columns by name where they have one and by index otherwise, since an index is no help when the matrix came from a data frame and a name is not available when it did not. This is a warning rather than an error because a single row is a legitimate way to get here: sd() of one value is NA.

Usage

warn_constant_columns(x, flat, what)

Arguments

x

The matrix being standardized.

flat

Logical vector marking the columns with no usable spread.

what

Name of the argument x came from, "theta" or "x".