i have trouble implementing back propogation for multi class classification of CIFAR10 dataset
My neural network has 2 layers
forward propagation
X -> L1 -> L2
weights w2 is initialized as random
np.random.randn(L1.shape[0], X.shape[0]) * 0.01
X is input of size (no_features * number of examples)
Z1 = (w1 * x) + b1
A1 = relu(Z1)
L1 has ReLu activation
Z2 = (w2 * A1) + b2
A2 = softmax(Z1)
L2 has softmax activation
cost is caluclated using this equation
cost = -(1/m)*np.sum((Y * np.log(A2) ) + ((1 - Y)*np.log(1-A2)))
back propagation
derivative of cost is calculated
dA2 = -(1/m)*(np.divide(Y, A2) - np.divide(1 - Y, 1 - A2))
dA2 = derivative of A2
Y = one hot encoded True values
now how do i proceed from here
how do i find dZ2 (derivative of Z2) using dA2