Error: missing the following mandatory columns: ..stratum_wt

[invain1218]

I am currently using the "smote" pipeline in my project to balance my dataset, which includes a strata variable. The tsk$strata is set to use the feature "wt" for stratification, and the target variable is vs (binary: 0-1).

Here's the code snippet I am using:

pob = po("encode") %>>% po("smote")
pro_tsk = pob$train(train_tsk)[[1]]

However, I encountered the following error:

Cannot rbind data to task 'classification', missing the following mandatory columns: ..stratum_wt
This happened in PipeOp traindata's $train()

It seems the issue is related to the missing strata variable during the pipeline execution. But I can't fix it.
Thank you in advance for your help! 😊

[mb706]

Sorry for the late response. The SMOTE pipeop tries to create new samples, but does not know how to fill the "strata" column for these samples. If you want to use SMOTE, you need to either remove the "strata" column altogether, or convert it into a feature column (you can convert it back to strata after the SMOTE pipeop), using po("colroles"). We now have the new_role_direct argument for po("colroles"), so you could do po("colroles", new_role_direct = list(stratum = NULL)) to remove the stratum column.