Kaggle competition: Leaf Classification
PATH = '.. /input/google-quest-challenge/'
BERT_PATH = '.. /input/bert-base-from-tfhub/bert_en_uncased_L-12_H-768_A-12'
tokenizer = tokenization.FullTokenizer(BERT_PATH+'/assets/vocab.txt', do_lower_case=True)
 MAX_SEQUENCE_LENGTH = 512
df_train = pd.read_csv(PATH+'train.csv')
 df_test = pd.read_csv(PATH+'test.csv')
 df_sub = pd.read_csv(PATH+'sample_submission.csv')
 print('train shape =', df_train.shape)
 print('test shape =', df_test.shape)
 output_categories = list(df_train.columns[11:])
 input_categories = list(df_train.columns[[1,2,5]])
 print('
output categories:
\t', output_categories)
 print('
input categories:
\t', input_categories )<string_transform>
train = pd.read_csv('.. /input/train.csv')
 test = pd.read_csv('.. /input/test.csv')
 print(train.shape)
 print(test.shape)
 test_ids = test.id
levels=train.species
train.drop(['species', 'id'], axis=1,inplace=True)
 test.drop(['id'],axis=1,inplace=True)
 print("after ")
 print(levels.shape)
 print(train.shape)
 print(test.shape)
 print("number of classes =",levels.unique().shape )
def _get_masks(tokens, max_seq_length):

 if len(tokens)> max_seq_length:
raise IndexError("Token length more than max seq length!")
 return [1] * len(tokens)+ [0] *(max_seq_length - len(tokens))
def _get_segments(tokens, max_seq_length):

 if len(tokens)>max_seq_length:
raise IndexError("Token length more than max seq length!")
 segments = []
first_sep = True
current_segment_id = 0
for token in tokens:
segments.append(current_segment_id)
 if token == "[SEP]":
if first_sep:
first_sep = False
else:
current_segment_id = 1
return segments + [0] *(max_seq_length - len(tokens))
def _get_ids(tokens, tokenizer, max_seq_length):

 token_ids = tokenizer.convert_tokens_to_ids(tokens)
 input_ids = token_ids + [0] *(max_seq_length-len(token_ids))
return input_ids
def _trim_input(title, question, answer, max_sequence_length,
t_max_len=30, q_max_len=239, a_max_len=239):
t = tokenizer.tokenize(title)
 q = tokenizer.tokenize(question)
 a = tokenizer.tokenize(answer)
 t_len = len(t)
 q_len = len(q)
 a_len = len(a)
 if(t_len+q_len+a_len+4)> max_sequence_length:
if t_max_len > t_len:
t_new_len = t_len
a_max_len = a_max_len + floor(( t_max_len - t_len)/2)
 q_max_len = q_max_len + ceil(( t_max_len - t_len)/2)
 else:
t_new_len = t_max_len
if a_max_len > a_len:
a_new_len = a_len
q_new_len = q_max_len +(a_max_len - a_len)
 elif q_max_len > q_len:
a_new_len = a_max_len +(q_max_len - q_len)
 q_new_len = q_len
else:
a_new_len = a_max_len
q_new_len = q_max_len
if t_new_len+a_new_len+q_new_len+4 != max_sequence_length:
raise ValueError("New sequence length should be %d, but is %d"
%(max_sequence_length,(t_new_len+a_new_len+q_new_len+4)))
 t = t[:t_new_len]
q = q[:q_new_len]
a = a[:a_new_len]
return t, q, a
def _convert_to_bert_inputs(title, question, answer, tokenizer, max_sequence_length):

 stoken = ["[CLS]"] + title + ["[SEP]"] + question + ["[SEP]"] + answer + ["[SEP]"]
input_ids = _get_ids(stoken, tokenizer, max_sequence_length)
 input_masks = _get_masks(stoken, max_sequence_length)
 input_segments = _get_segments(stoken, max_sequence_length)
 return [input_ids, input_masks, input_segments]
def compute_input_arays(df, columns, tokenizer, max_sequence_length):
input_ids, input_masks, input_segments = [], [], []
for _, instance in tqdm(df[columns].iterrows()):
t, q, a = instance.question_title, instance.question_body, instance.answer
t, q, a = _trim_input(t, q, a, max_sequence_length)
 ids, masks, segments = _convert_to_bert_inputs(t, q, a, tokenizer, max_sequence_length)
 input_ids.append(ids)
 input_masks.append(masks)
 input_segments.append(segments)
 return [np.asarray(input_ids, dtype=np.int32),
np.asarray(input_masks, dtype=np.int32),
np.asarray(input_segments, dtype=np.int32)]
def compute_output_arrays(df, columns):
return np.asarray(df[columns] )<compute_test_metric>
le=LabelEncoder().fit(levels)
 levels=le.transform(levels )
def compute_spearmanr(trues, preds):
rhos = []
for col_trues, col_pred in zip(trues.T, preds.T):
rhos.append(
 spearmanr(col_trues, col_pred + np.random.normal(0, 1e-7, col_pred.shape[0])).correlation)
 return np.mean(rhos)
 class CustomCallback(tf.keras.callbacks.Callback):
def __init__(self, valid_data, test_data, batch_size=16, fold=None):
self.valid_inputs = valid_data[0]
self.valid_outputs = valid_data[1]
self.test_inputs = test_data
self.batch_size = batch_size
self.fold = fold
def on_train_begin(self, logs={}):
self.valid_predictions = []
self.test_predictions = []
def on_epoch_end(self, epoch, logs={}):
self.valid_predictions.append(
 self.model.predict(self.valid_inputs, batch_size=self.batch_size))
rho_val = compute_spearmanr(
 self.valid_outputs, np.average(self.valid_predictions, axis=0))
print("
validation rho: %.4f" % rho_val)
 if self.fold is not None:
self.model.save_weights(f'bert-base-{fold}-{epoch}.h5py')
 self.test_predictions.append(
 self.model.predict(self.test_inputs, batch_size=self.batch_size)
)
 def bert_model() :
input_word_ids = tf.keras.layers.Input(
(MAX_SEQUENCE_LENGTH,), dtype=tf.int32, name='input_word_ids')
 input_masks = tf.keras.layers.Input(
(MAX_SEQUENCE_LENGTH,), dtype=tf.int32, name='input_masks')
 input_segments = tf.keras.layers.Input(
(MAX_SEQUENCE_LENGTH,), dtype=tf.int32, name='input_segments')
 bert_layer = hub.KerasLayer(BERT_PATH, trainable=True)
 _, sequence_output = bert_layer([input_word_ids, input_masks, input_segments])
 x = tf.keras.layers.GlobalAveragePooling1D()(sequence_output)
 x = tf.keras.layers.Dropout(0.2 )(x)
 y = tf.keras.layers.BatchNormalization(epsilon=1e-06, momentum=0.9, weights=None)
 out = tf.keras.layers.Dense(30, activation="sigmoid", name="dense_output" )(x)
 model = tf.keras.models.Model(
 inputs=[input_word_ids, input_masks, input_segments], outputs=out)
 return model
def train_and_predict(model, train_data, valid_data, test_data,
learning_rate, epochs, batch_size, loss_function, fold):
custom_callback = CustomCallback(
 valid_data=(valid_data[0], valid_data[1]),
test_data=test_data,
batch_size=batch_size,
fold=None)
 optimizer = tf.keras.optimizers.Adam(learning_rate=learning_rate)
 model.compile(loss=loss_function, optimizer=optimizer)
 model.fit(train_data[0], train_data[1], epochs=epochs,
batch_size=batch_size, callbacks=[custom_callback])
 return custom_callback<split>
Model=RandomForestClassifier(n_estimators=1000)
 Model = cc(Model, cv=3, method='isotonic')
 Model.fit(train, levels )
<choose_model_class><EOS> 
predictions = Model.predict_proba(test)
 print(predictions.shape)
 sub = pd.DataFrame(predictions, columns=list(le.classes_))
sub.insert(0, 'id', test_ids)
 sub.reset_index()
sub.to_csv('submit.csv', index = False)
 sub.head()