concurrent.futuresでMemoryErrorが発生する

Question

from tqdm import tqdm
import concurrent.futures
import numpy as np

class PredictData:
  def __init__(self,X_train_trans,X_test_trans,y_train,y_test):
    self.X_train_trans=X_train_trans
    self.X_test_trans=X_test_trans
    self.y_train=y_train
    self.y_test=y_test
    print(self.X_train_trans.shape)
    print(self.X_test_trans.shape)

  def forcount(self,random_st):
      print('start')
      param=[_ for _ in range(5)]
      for i in tqdm(range(1,3)):
        for j in tqdm(range(1,2)):
          for k in tqdm(np.arange(.01,.02,.01)):
            forest=GradientBoostingClassifier(random_state=random_st,n_estimators=i,max_depth=j,learning_rate=k)
            forest=forest.fit(self.X_train_trans,self.y_train)
            if forest.score(self.X_test_trans,self.y_test) > param[0]:
              param[0]=forest.score(self.X_test_trans,self.y_test)
              param[1]=forest.score(self.X_train_trans,self.y_train)
              param[2]=i
              param[3]=j
              param[4]=k
      return param  
  
  def GraForestCl_predict_data(self):
    print(self.forcount(0))
    print('並行')
    with concurrent.futures.ProcessPoolExecutor(2) as executor:
      print('開始')
      futures=[executor.submit(self.forcount,i) for i in tqdm(range(2))]
      print('途中')
      for future in tqdm(concurrent.futures.as_completed(futures)):
        # test_score,train_score,n_es,max,rate=future.result()
        print(future.result())
        print()
if __name__ =='__main__':
  prd=PredictData(X_train_trans,X_test_trans,y_train,y_test)
  prd.GraForestCl_predict_data()

'''
(8210, 4140)
(2733, 4140)
start
100%|███████████████████████████████████████████████████████████████████████████| 1/1 [00:03<00:00,  3.15s/it] 
100%|███████████████████████████████████████████████████████████████████████████| 1/1 [00:03<00:00,  3.15s/it]
100%|███████████████████████████████████████████████████████████████████████████| 1/1 [00:01<00:00,  1.26s/it] 
100%|███████████████████████████████████████████████████████████████████████████| 1/1 [00:01<00:00,  1.26s/it] 
100%|███████████████████████████████████████████████████████████████████████████| 2/2 [00:04<00:00,  2.22s/it] 
[0.7939992682034395, 0.7884287454323995, 1, 1, 0.01]
並行
開始
100%|███████████████████████████████████████████████████████████████████████████| 2/2 [00:00<00:00, 48.65it/s]
途中
0it [00:00, ?it/s]
MemoryError
exception: no description
File "data_predicting.py", line 67, in GraForestCl_predict_data
  print(future.result())
File "data_predicting.py", line 78, in <module>
  prd.GraForestCl_predict_data()
'''

forcount関数単体で与えたデータ基に処理すると正常に動きますが、並行処理しようとするとうまくいきません。print(future.result())でMemoryErrorを吐いています。これは自分の使っているPCの性能の問題なのでしょうか？データを前処理することで解決できますか？あいまいな表現で申し訳ありません。