weight <- as.numeric(labels) * nrow(test) / length(labels)
upscale <- sum(weight * (labels == 1.0))

xgb_params = list(
  objective = 'binary:logistic',
  eta = 0.1,
  max_depth = 4,
  eval_metric = 'auc',
  max_delta_step = 10,
  scale_pos_weight = upscale
)