Table 2 Optimized hyperparameters of the machine learning models for predicting the CS of SFRC CS.

From: Application of machine learning techniques to predict the compressive strength of steel fiber reinforced concrete

Machine learning model

Optimized values/types of key hyperparameters

KNN

n_neighbors = 5

SVR

kernel = RBF

C = 6

gamma = 0.2

epsilon = 0.1

GPR

kernel = ConstantKernel(50)*RBF(1) + RBF(1)

alpha = 1

random_state = 1

RFR

n_estimators = 200

max_depth = 70

max_features = 9

min_samples_split = 2

min_samples_leaf = 1

bootstrap = True

XGBR

colsample_bytree = 0.7

n_estimators = 200

learning_rate = 0.02

max_depth = 8

ANN

hidden layers = 2

number of neurons = 1 st hidden layer: 64, 2nd hidden layer: 32

activation = ReLU

optimizer = Adam

learning rate = 0.001

batch size = 32

epochs = 100

loss function = MSE