Question

我跟随Pinheiro＆amp; Bates 2000 pp.345。我想适应一个nls模型，并修改了一个逻辑模型。我想创建一个自启动功能，但错误显示。当我运行“logist3P”时，模型公式中没有出现错误“参数'标尺'”。我认为问题是因为我为“scal”参数设置了一个公式。如何将“scal”的公式放入并避免错误？

logistin3P <- function(mCall, LHS, data)
{
  xy <- sortedXyData(mCall[["x"]], LHS, data)
  if(nrow(xy)<3) {stop("Too few distinct input values to fit a logistic")}
  Asym <- max(abs(xy[,"y"]))
  if(Asym !=max(xy[,"y"])) Asym <- -Asym #negative asymptote
  xmid <- NLSstClosestX(xy, 0.5 * Asym)
  scal <- (((log(Asym)+log(Asym*0.75))/ log(Asym*0.75))/((xmid*1.5)-xmid))         
  value <- c(Asym, xmid, scal)
  names(value) <- mCall[c("Asym","xmid","scal")]
  value
}

logist3P <- selfStart(~Asym/(1+exp(- scal(x-xmid))), initial = logistin3P, parameters = c("Asym","xmid","scal"))

Answer 1

我相信您在模型参数中的*之后缺少scal：

logist3P <- selfStart(~Asym/(1+exp(- scal*(x-xmid))), initial = logistin3P, parameters = c("Asym","xmid","scal"))

新的自启动功能

1 个答案: