“…The candidate for the number of estimator is set as: [10,20,50,100,150,200,250,300]. The candidates for the loss function, the max_depth, and the learning rate are set as ['linear', 'square', 'exponential'], [3,5,7,9,12,15,18,21,25], and [0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1], accordingly. The total search space size is 8×3×9×7.…”