import tensorflow as tf

            # Optimizer for Non-Variational Autoencoders
            if model_name in ('gcn_ae', 'linear_ae', 'deep_gcn_ae'):
                opt = OptimizerAE(preds = model.reconstructions,
                                  labels = tf.reshape(tf.sparse_tensor_to_dense(placeholders['adj_orig'],
                                                                                validate_indices = False), [-1]),
                                  pos_weight = pos_weight,
