R solve.default（H，g[！fixed]）中的mlogit错误：Lapack例程dgesv:系统完全是单数的：U[2,2]=0

我想将我的数据转换为mlogit.data，我这样做了

a<- mlogit.data(Fit.Train.KNN, choice ="Vote", 
                shape = c("wide"),
  alt.levels = c( "Scioli","Macri",
                  "Massa", "Carrio", "Sanz ","Stolbizer", "Indecisos", "Voto en blanco"))

Model.mulnom<- mlogit("Vote " ~ "Gender" , shape = c("long"), id="id",
                        alt.levels = c( "Scioli","Macri",
                                        "Massa", "Carrio", 
                                        "Sanz ","Stolbizer", "Indecisos", 
                                        "Voto en blanco") ,
                        reflevel= "Scioli",choice = "Vote", data= a
                        ) 

**Error in solve.default(H, g[!fixed]) : 

  Lapack routine dgesv: system is exactly singular: U[2,2] = 0**