diff --git a/src/UnitTests/Matrices/SparseMatrixTest.h b/src/UnitTests/Matrices/SparseMatrixTest.h
index 0846dc5a6187b34ad265bd64a66cd153483b271e..69a4d70225679360c95ccf56c244f89050340609 100644
--- a/src/UnitTests/Matrices/SparseMatrixTest.h
+++ b/src/UnitTests/Matrices/SparseMatrixTest.h
@@ -57,6 +57,8 @@
 // GENERAL TODO
 /*
  * For every function, EXPECT_EQ needs to be done, even for zeros in matrices.
+ * Figure out __cuda_callable_. When trying to call __cuda_callable__ functions
+ *      a segmentation fault (core dumped) is thrown.
  */