Tuning parameters in Affinity Propagation

Question

I am doing Affinity Propagation clustering and trying to do tuning, but it takes time. A lot of time actually. As I am beginner I do not know how to get clusters. I need cluster numbers from 1 to 20 for example. Without any evaluation.

from sklearn.metrics import silhouette_samples, silhouette_score
from sklearn.cluster import AffinityPropagation

final_n_clusters = []
preference = np.arange(-1,1,0.1) # HERE
iter_value = np.arange(1,10,1)   # and HERE
iter_value = np.array(iter_value, dtype=np.int32)

for k in preference:
    n_cluster_list = []
    for j in iter_value:
        af = AffinityPropagation(preference = k, max_iter = j, affinity='precomputed').fit(X)
        labels = af.labels_
        n_clusters = len(np.unique(labels))
        n_cluster_list.append(n_clusters)
    final_n_clusters.append(n_cluster_list)