R/linloglines.R

In TIMP: Fitting Separable Nonlinear Models in Spectroscopy and Microscopy

"linloglines" <-
  function(x, mu, alpha) {
    if (alpha != 0) {
      for (i in 1:length(x)) {
        if ((x[i] - mu) / alpha >= 1) {
          x[i] <- alpha + (alpha * log10((x[i] - mu) / alpha))
        } else if ((x[i] - mu) / alpha < -1) {
          x[i] <- -alpha - (alpha * log10((mu - x[i]) / alpha))
        } else {
          x[i] <- x[i] - mu
        }
      }
    } else {
      for (i in 1:length(x)) {
        x[i] <- x[i] - mu
      }
    }
    x
  }