r - gam() 中的“非列表对比参数被忽略”

Question

我收到以下警告non-list contrasts argument ignored。有人知道出了什么问题吗？谢谢。

R> tmp=data.frame(x=seq_len(100), y=rpois(seq_len(100), lambda=seq_len(100)/10))
R> library(gam)
Loading required package: splines
Loading required package: foreach
Loaded gam 1.16.1

Warning message:
package ‘foreach’ was built under R version 3.6.2 
R> fit=gam(y~s(x), family=poisson, data=tmp)
Warning message:
In model.matrix.default(mt, mf, contrasts) :
  non-list contrasts argument ignored

标签： rgam