diff --git a/operators/cuda/add_mul.h b/operators/cuda/add_mul.h
index b51282f94..1aea73e1f 100644
--- a/operators/cuda/add_mul.h
+++ b/operators/cuda/add_mul.h
@@ -29,6 +29,14 @@ inline void _FillOutputShape3Op(std::vector<int64_t>& dimsA,
     }
 }
 
+/**
+*  AddOrMulSharedInput(A, B, C) = A + B, A + C ifaddition is true
+*  AddOrMulSharedInput(A, B, C) = A * B, A * C ifaddition is false
+*
+*  The operator supports broadcast on first dimensions.
+*  A[1, J] + B[I, J] is supported,
+*  A[1, J, 1] + B[I, J, K] is not supported,
+*/
 template <typename T, bool addition>
 struct AddOrMulSharedInput {
   template <typename TDict>
@@ -61,6 +69,14 @@ struct AddOrMulSharedInput {
   }
 };
 
+/**
+*  AddOrMulTwice(A, B, C) = A + B + C ifaddition is true
+*  AddOrMulTwice(A, B, C) = A * B * C ifaddition is false
+*
+*  The operator supports broadcast on first dimensions.
+*  A[1, J] + B[I, J] is supported,
+*  A[1, J, 1] + B[I, J, K] is not supported,
+*/
 template <typename T, bool addition>
 struct AddOrMulTwice {
   template <typename TDict>
@@ -97,6 +113,17 @@ struct AddOrMulTwice {
   }
 };
 
+/**
+*  AddAndMul(A, B, C) = (A + B) * C if addition_first is true
+*  AddAndMul(A, B, C) = A * B + C if addition_first is false
+*
+*  The operator supports broadcast on first dimensions.
+*  A[1, J] + B[I, J] is supported,
+*  A[1, J, 1] + B[I, J, K] is not supported,
+*
+* If switchMiddleAxis is true, then the output is transposed, then
+* AddAndMul(A, B, C, switchMiddleAxis=1) = Transpose((A + B) * C, perm=[0, 2, 1, 3])
+*/
 template <typename T, bool addition_first>
 struct AddAndMul {
   template <typename TDict>
@@ -154,6 +181,17 @@ struct AddAndMul {
   bool switchMiddelAxis_;
 };
 
+/**
+*  SubAndMul(A, B, C) = (A - B) * C if subtract_first is true
+*  SubAndMul(A, B, C) = A * B - C if subtract_first is false
+*
+*  The operator supports broadcast on first dimensions.
+*  A[1, J] + B[I, J] is supported,
+*  A[1, J, 1] + B[I, J, K] is not supported,
+*
+* If negative is true, then the output is transposed, then
+* SubAndMul(A, B, C, negative=1) = (B - A) * C
+*/
 template <typename T, bool subtract_first>
 struct SubAndMul {
   template <typename TDict>