Table 1.

Approximated activation functions parameters.

Tanh
Input interval	Output
x ≥ 2.375	y=1
1.5 ≤ x < 2.375	y=0.09375x+0.765625
1 ≤ x < 1.5	y=0.28125x+0.484375
0.5 ≤ x < 1	y=0.59375x+0.171875
−0.5 ≤ x < 0.5	y=0.9375x
−1 ≤ x < −0.5	y=0.59375x − 0.171875
−1.5 ≤ x < −1	y=0.28125x − 0.484375
−2.375 ≤ x < −1.5	y=0.09375x − 0.765625
x < −2.375	y=−1
Sigmoid
Input interval		Output
x ≥ 5		y=1
2.375 ≤ x < 5		y=0.03125x+0.84375
1 ≤ x < 2.375		y=0.125x+0.625
−1 ≤ x < 1		y=0.25x+0.5
−2.375 ≤ x < −1		y=0.125x+0.375
−5 ≤ x < −2.375		y=0.03125x+0.15625
x < −5		y=0