README.md

Jigsaw Unintended Bias in Toxicity Classification

This respository contains my code for competition in kaggle.

7th Place Solution for Jigsaw Unintended Bias in Toxicity Classification

Team: Abhishek Thakur, Duy, R0seNb1att, atfujita

All models(Team)
Public LB: 0.94729(3rd)
Private LB: 0.94660(7th)

Note: This repository contains only my models and only train script.

My models(5 Model averaging)
Public LB: 0.94719
Private LB: 0.94651

Thanks to Abhishek and Duy's wonderful models and support, I was able to get better results.

Set up

• Particularly important libraries are listed in requirements.txt

Models

I created 5 models

• LSTM

  • Based on the Quora competition model
  • Architecture: LSTM + GRU + Self Attention + Max pooling
  • Word embeddings: concat glove and fasttext.
  • Optimizer: AdamW
  • Train:
    • max_len = 220
    • n_splits = 10
    • batch_size = 512
    • train_epochs = 7
    • base_lr, max_lr = 0.0005, 0.003
    • Weight Decay = 0.0001
    • Learning schedule: CyclicLR

• BERT

  • The model is based on yuval reina's graet kernel
  • Changes are loss function and preprocessing.
  • I created 4 BERT models.
    • BERT-Base Uncased
    • BERT-Base Cased
    • BERT-Large Uncased(Whole Word Masking)
    • BERT-Large Cased(Whole Word Masking)
  • Train:
    • max_len = 220
    • train samples = 1.7M, val samples= 0.1M
    • batch_size = 32(Base), 4(Large)
    • accumulation_steps = 1(Base), 16(Large)
    • train_epochs = 2
    • lr = 2e-5

Worked well

The loss function was very important in this competition.
In fact, all winners used different loss functions.

My loss function is below.

y_columns = ['target']

y_aux_train = train_df[['target', 'severe_toxicity', 'obscene',
                        'identity_attack', 'insult',
                        'threat',
                        'sexual_explicit'
                        ]]

y_aux_train = y_aux_train.fillna(0)

identity_columns = [
    'male', 'female', 'homosexual_gay_or_lesbian', 'christian', 'jewish',
    'muslim', 'black', 'white', 'psychiatric_or_mental_illness']
# Overall
weights = np.ones((len(train_df),)) / 4
# Subgroup
weights += (train_df[identity_columns].fillna(0).values >= 0.5).sum(
    axis=1).astype(bool).astype(np.int) / 4
# Background Positive, Subgroup Negative
weights += (((train_df['target'].values >= 0.5).astype(bool).astype(np.int) +
             (train_df[identity_columns].fillna(0).values < 0.5).sum(
                 axis=1).astype(bool).astype(np.int)) > 1).astype(
    bool).astype(np.int) / 4
# Background Negative, Subgroup Positive
weights += (((train_df['target'].values < 0.5).astype(bool).astype(np.int) +
             (train_df[identity_columns].fillna(0).values >= 0.5).sum(
                 axis=1).astype(bool).astype(np.int)) > 1).astype(
    bool).astype(np.int) / 4

y_train = np.vstack(
    [(train_df['target'].values >= 0.5).astype(np.int), weights]).T

y_train = np.hstack([y_train, y_aux_train])


def custom_loss(data, targets):
    ''' Define custom loss function for weighted BCE on 'target' column '''
    bce_loss_1 = nn.BCEWithLogitsLoss(
        weight=targets[:, 1:2])(data[:, :1], targets[:, :1])
    bce_loss_2 = nn.BCEWithLogitsLoss()(data[:, 1:2], targets[:, 2:3])
    bce_loss_3 = nn.BCEWithLogitsLoss()(data[:, 2:3], targets[:, 3:4])
    bce_loss_4 = nn.BCEWithLogitsLoss()(data[:, 3:4], targets[:, 4:5])
    bce_loss_5 = nn.BCEWithLogitsLoss()(data[:, 4:5], targets[:, 5:6])
    bce_loss_6 = nn.BCEWithLogitsLoss()(data[:, 5:6], targets[:, 6:7])
    bce_loss_7 = nn.BCEWithLogitsLoss()(data[:, 6:7], targets[:, 7:8])
    bce_loss_8 = nn.BCEWithLogitsLoss()(data[:, 7:8], targets[:, 8:9])

    return bce_loss_1 + bce_loss_2 + bce_loss_3 + bce_loss_4 \
           + bce_loss_5 + bce_loss_6 + bce_loss_7 + bce_loss_8