Table 2 Hyperparameter details.

From: Optimized hierarchical CLSTM model for sentiment classification of tweets using boosted killer whale predation strategy

Hyperparameter

Description

Search Range / Value

Number of convolutional blocks

Number of hierarchical LFTBs with CLSTM

4

Filters per conv layer

Number of filters in each block

[32, 64, 128, 256]

Kernel size

Size of 1D convolutional kernel

3

Pooling type

Downsampling method

Max Pooling

Batch normalization

After each convolutional block

Applied

LSTM units

Number of hidden units in the LSTM layer

[64, 128, 256]

GRU units (GFTB)

Number of units in global GRU stack

[64, 128, 256]

Dense layers

Number and size of dense layers after LSTM

2 layers: [128, 64]

Dropout rate

Dropout is applied to prevent overfitting

[0.2, 0.3, 0.4, 0.5]

Learning rate

Learning rate for optimizer

[0.0001, 0.001, 0.01]

Batch size

Number of samples per training batch

[32, 64, 128]

Activation Function

Activation used in dense layers

ReLU

Output activation

Final classification activation

Sigmoid

Loss function

A combination of classification and distance loss

Softmax + Center Loss (λ tuned)

Epochs

Maximum training iterations

50