調整xgboost參數時，循環無法在R中按預期工作

Question

該問題基於：

R中的xgboost：xgb.cv如何將最佳參數傳遞給xgb.train

我試圖用不同的參數類似地循環：

for (iter in 1:100){

param <- list(objective = "binary:logistic",
              eval_metric = "auc",
              max_depth = sample(2:6,1),
              eta = runif(.01,.1,.05),
              gamma = runif(.01,.05,.1), 
              subsample = runif(.9,.8,.7),
              colsample_bytree = runif(.8,.9,.5), 
              min_child_weight = sample(30:100,1),
              max_delta_step = sample(1:10,1)
)

但這會引發錯誤，因為參數在第一次迭代時將值取為：

max_depth : int 6
eta : num(0)
gamma: num(0)
subsample : num(0)
colsample_bytree : num(0)
min_child_weight: int 63
max_delta_step: int 2

是什么導致這種行為？

Answer 1

好像我弄錯了runif函數。

這似乎正在工作：

param <- list(objective = "binary:logistic",
              eval_metric = "auc",
              max_depth = sample(2:6,1),
              eta = runif(1,.01,.05),
              gamma = runif(1,.01,.1), 
              subsample = runif(1,0.6,0.9),
              colsample_bytree = runif(1,.5,1), 
              min_child_weight = sample(30:100,1),
              max_delta_step = sample(1:10,1)