A Reliable PSO-based ANN Approach for Predicting Unconfined Compressive Strength of Sandstones

Table 4: The effect of the hidden nodes on the prediction performance of the PSO-based ANN predictive model.

Number of Nodes	3				4				5
Model Number	R²		RMSE		R²		RMSE		R²		RMSE
Model Number	Test	Train	Test	Train	Test	Train	Test	Train	Test	Train	Test	Train
I	0.964	0.948	0.467	0.109	0.96	0.942	0.38	0.387	0.98	0.944	0.469	0.114
II	0.90	0.946	0.469	0.122	0.98	0.94	0.007	0.130	0.91	0.96	0.146	0.110
III	0.980	0.942	0.140	0.114	0.964	0.944	0.08	0.130	0.97	0.946	0.100	0.122
IV	0.946	0.948	0.109	0.126	0.946	0.952	0.126	0.114	0.98	0.942	0.086	0.119
V	0.974	0.941	0.089	0. 126	0.904	0.940	0.14	0.13	0.976	0.947	0.097	0.119