直接安装 nnet 包，运用nnet 函数来训练模型，我试着写了一个例子，用nnet 包拟合 sin 正弦函数，希望能够有帮助 y = 0.5 + 0.4 * sin(2pi * x)

        library(nnet)
        xTrain <- rbind(cbind(runif(150,min = 0,max = 0.5),runif(150,min = 0, max = 0.5)) ,
cbind(runif(150,min = 0.5, max =1),runif(150,min = 0.5, max = 1))
)
        nObs <- dim(xTrain)[1]
        yTrain <- 0.5 + 0.4 * sin(2* pi * xTrain%*% c(0.4,0.6)) +rnorm(nObs,mean = 0, sd = 0.05)
        plot(xTrain %*% c(0.4,0.6),yTrain)
        # Training nnet models
        net <- nnet(yTrain ~ xTrain,size = 3,rang = 0.1,decay = 5e-4, maxit = 500)
        wts <- net$wts

# 还试着用 nnetpredint包来添加预测的置信区间
https://bbs.pinggu.org/thread-4156657-1-1.html