diff --git a/clctm.py b/clctm.py
index 67ed033..b75395b 100644
--- a/clctm.py
+++ b/clctm.py
@@ -294,16 +294,18 @@ def _init_concept_vectors(self, corpus, sample_size=0.01, method="kmeans++", met
                 
                 # step 1
                 distidx = faiss.IndexFlatL2(self.n_dims)
-                self.concept_vectors = [samp[np.random.choice(sampsize)]]
-                distids.add(np.array(self.concept_vectors))
+                cvs = [np.random.choice(sampsize)]
+                distidx.add(self.concept_vectors[cvs[0]:cvs[0]+1)
 
-                for i in tqdm.trange(1, self.n_concepts, desc="Kmeans++ initialization"):
+                for i in tqdm.trange(1, self.n_concepts, desc="Kmeans++ initialization (with faiss)"):
                     #step 2
                     D, _ = distidx.search(samp, 1)
 
                     #step 3
-                    self.concept_vectors = np.concatenate((self.concept_vectors, [samp[np.random.choice(sampsize, p=D.T[0]/D.sum())]]))
-                    distidx.add(self.concept_vectors[:-1])
+                    cvs.append(p.random.choice(sampsize, p=D.T[0]/D.sum()))
+                    distidx.add(self.concept_vectors[cvs[-1]:cvs[-1]+1])
+
+                selv.concept_vectors = samp[cvs]
 
             else:
                 samp = corpus.token_vectors[np.random.choice(len(corpus.input_ids), sampsize)]