diff --git a/strawberryfields/backends/gaussianbackend/ops.py b/strawberryfields/backends/gaussianbackend/ops.py
index c8b608725..a56e4cceb 100644
--- a/strawberryfields/backends/gaussianbackend/ops.py
+++ b/strawberryfields/backends/gaussianbackend/ops.py
@@ -19,8 +19,8 @@
 def chop_in_blocks(m, idtodelete):
     """
     Splits a (symmetric) matrix into 3 blocks, A, B, C
-    Blocks A and B are diagonal blocks and C is the offdiagonal block
-    idtodelete specifies which indices go into B.
+    Blocks A and C are diagonal blocks and B is the offdiagonal block
+    idtodelete specifies which indices go into C.
     """
     A = np.copy(m)
     A = np.delete(A, idtodelete, axis=0)