Clarify awful min_sample condition

PopPUNK/models.py

@@ -513,7 +513,8 @@ def fit(self, X, max_num_clusters, min_cluster_prop, use_gpu = False):
 
         # DBSCAN parameters
         cache_out = "./" + self.outPrefix + "_cache"
-        min_samples = min(int(min_cluster_prop * self.subsampled_X.shape[0]), 1023)
+        min_samples = max(int(min_cluster_prop * self.subsampled_X.shape[0]), 10) # do not allow clusters of < 10 points
+        min_samples = min(min_samples,1023) # do not allow clusters to require more than 1023 points at the start
         min_cluster_size = max(int(0.01 * self.subsampled_X.shape[0]), 10)
 
         # Check on initialisation of GPU libraries and memory