added 2 functions

Author: edwardyang12

Fall20/NeuralNetworks1/NN.py

@@ -0,0 +1,44 @@
+import numpy as np
+
+def linear_activation(z):
+    return z
+
+def parametric_activation(a,z):
+    if z<=0:
+        return a*z
+    else:
+        return z
+
+def tanh_activation(z):
+    return np.tanh(z)
+    
+# 2 layer NN for implementation of OR gate
+def orgate(x):
+    weights = np.array([2,2])
+    bias = -1
+    weighted_input = np.matmul(weights,x) + bias
+    y = linear_activation(weighted_input)
+    return y
+
+x = np.array([0,0])
+print(orgate(x))
+
+# 4 layer NN for computing whether absolute difference is between 1 and 3
+# if between 1 and 3 outputs >0 else output <=0
+def multilayer(x):
+    w1 = np.array([1,-1])
+    b1 = 0
+    weighted_input1 = np.matmul(w1,x) + b1
+    output1 = parametric_activation(-1,weighted_input1)
+    w2 = np.array([1])
+    b2 = -2
+    weighted_input2 = np.matmul(w2,[output1]) + b2
+    output2 = parametric_activation(-1,weighted_input2)
+    w3 = np.array([-1])
+    b3 = 1
+    weighted_input3 = np.matmul(w3,[output2]) + b3
+    y = tanh_activation(weighted_input3)
+    return y
+
+x = np.array([4,5.5])
+print(multilayer(x))