update_parameters_momentum.py

def update_parameters_with_momentum(parameters, grads, v, beta, learning_rate):

    L = len(parameters) // 2 # number of layers in the neural networks
    
    # Momentum update for each parameter
    for l in range(L):
        # compute velocities
        v["dW" + str(l+1)] = beta*v["dW" + str(l+1)]+(1-beta)*grads["dW"+str(l+1)]
        v["db" + str(l+1)] = beta*v["db" + str(l+1)]+(1-beta)*grads["db"+str(l+1)]
        # update parameters
        parameters["W" + str(l+1)] = parameters["W" + str(l+1)] - learning_rate*v["dW" + str(l+1)]
        parameters["b" + str(l+1)] = parameters["b" + str(l+1)] - learning_rate*v["db" + str(l+1)]
        
    return parameters, v