diff --git a/gensim/models/atmodel.py b/gensim/models/atmodel.py
index 4f550b9ffe..c3987ceef0 100755
--- a/gensim/models/atmodel.py
+++ b/gensim/models/atmodel.py
@@ -391,15 +391,17 @@ def inference(self, chunk, author2doc, doc2author, rhot, collect_sstats=False, c
                 doc_no = d
             # Get the IDs and counts of all the words in the current document.
             # TODO: this is duplication of code in LdaModel. Refactor.
+
             if doc and not isinstance(doc[0][0], six.integer_types):
                 # make sure the term IDs are ints, otherwise np will get upset
                 ids = [int(id) for id, _ in doc]
             else:
                 ids = [id for id, _ in doc]
-            cts = np.array([cnt for _, cnt in doc])
+            ids = np.array(ids, dtype=np.integer)
+            cts = np.array([cnt for _, cnt in doc], dtype=np.integer)
 
             # Get all authors in current document, and convert the author names to integer IDs.
-            authors_d = [self.author2id[a] for a in self.doc2author[doc_no]]
+            authors_d = np.array([self.author2id[a] for a in self.doc2author[doc_no]], dtype=np.integer)
 
             gammad = self.state.gamma[authors_d, :]  # gamma of document d before update.
             tilde_gamma = gammad.copy()  # gamma that will be updated.
@@ -828,9 +830,9 @@ def bound(self, chunk, chunk_doc_idx=None, subsample_ratio=1.0, author2doc=None,
             else:
                 doc_no = d
             # Get all authors in current document, and convert the author names to integer IDs.
-            authors_d = [self.author2id[a] for a in self.doc2author[doc_no]]
-            ids = np.array([id for id, _ in doc])  # Word IDs in doc.
-            cts = np.array([cnt for _, cnt in doc])  # Word counts.
+            authors_d = np.array([self.author2id[a] for a in self.doc2author[doc_no]], dtype=np.integer)
+            ids = np.array([id for id, _ in doc], dtype=np.integer)  # Word IDs in doc.
+            cts = np.array([cnt for _, cnt in doc], dtype=np.integer)  # Word counts.
 
             if d % self.chunksize == 0:
                 logger.debug("bound: at document #%i in chunk", d)