R/ScaleAdv.R

In pcaPP: Robust PCA by Projection Pursuit

ScaleAdv <- function (x, center = mean, scale = sd)
{
	if (!is.matrix (x))
	{
		if (is.data.frame (x))
			x = as.matrix(x)
		else
			x = matrix (x, ncol = 1)
	}
	n = nrow (x)
	p = ncol (x)

	m = array (0, p)

	if (missing (scale))	## 2be removed as soon as the matrix-warning message in "sd" disappears.
		scale <- .colSds

	if (is.character (center))
		center = eval (parse (text = center))

	if (is.function (center))
	{
		m = center (x)
		
		if (is.list (m))
			m <- m$par
		else if (length (m) != p)
			m = apply (x, 2, center)
		x = x - matrix(1, nrow = n) %*% m
	}
	else if (length (center) == p & is.numeric (center))
	{
		m = center
		x = x - matrix(1, nrow = n) %*% m
	}
	else if (!is.null (center))
		warning ("Unknown center specification! Centering will be omitted.\n")

	s = array (1, p)
	if (is.character (scale))
		scale = eval (parse (text = scale))

	if (is.function (scale))
	{
		s = scale (x)
		if (length (s) != p)
			s = apply (x, 2, scale)
		x = x / matrix(1, nrow = n) %*% s
	}
	else if (length (scale) == p & is.numeric (scale))
	{
		s = scale
		x = x / matrix(1, nrow = n) %*% s
	}
	else if (!is.null (scale))
		warning ("Unknown scale specification! Scaling will be omitted.\n")

	return (list (x = x, center = m, scale = s))
}