错误：“使用mlr3优化参数”消息

Question

我使用参数优化(随机搜索)与mlr3，但它给了我以下错误。我也尝试过其他型号(kknn)，但同样的错误也出现了。

Error: Resampling 'cv' may not be instantiated

///My code is here 

data = readARFF("xerces.arff")
index= sample(1:nrow(data), 0.7*nrow(data))
train= data[index,]
test= data[-index,]
task = TaskRegr$new("data", backend = train, target = "bug")

learner5=lrn("regr.randomForest")
resampling_cv = rsmp("cv", folds = 10L)
resampling_cv$instantiate(task)
measure= msr("regr.mae")

search_space = paradox::ParamSet$new(
 params = list(paradox::ParamInt$new("ntree", lower = 100, upper = 500)))

terminator = trm("evals", n_evals = 30)
tuner = tnr("random_search")

at = AutoTuner$new(
        learner = learner5,
        resampling = resampling_cv,
        measure = measure,
        search_space = search_space,
        terminator = terminator,
        tuner = tuner,  store_tuning_instance = TRUE,
        store_benchmark_result = TRUE,
        store_models = TRUE
)

Answer 1

使用resampling_cv$instantiate(task)实例化重采样。删除这一行，它就能工作了。