#
# A self-started function for the model
#
# f(x) = a +(b-a)(1 - exp(-c x))
#
oneMinusExpModel = function(predictor, a, b, c){
    a + (b-a)*(1 - exp(-c*predictor))
}

oneMinusExpModelInit = function(mCall, LHS, data){
    xy = sortedXyData(mCall[['predictor']], LHS, data)

    a0 = min(xy$y)* 0.9
    b0 = max(xy$y)* 1.1
    
    Y = log(1 -(xy$y - a0)/(b0 - a0))
    X = xy$x
    lmFit = lm(Y ~ X - 1)
    coefs = as.double(coef(lmFit))
    c0 = -coefs[1]
    
    value = c(a0, b0, c0)
    names(value)= mCall[c('a','b','c')]
    value
}

SSoneMinusExp = selfStart(oneMinusExpModel, oneMinusExpModelInit, c('a', 'b', 'c'))