diff --git a/Eigen/src/Core/arch/CUDA/PacketMathHalf.h b/Eigen/src/Core/arch/CUDA/PacketMathHalf.h
index 4a10e4fa5..bd42cb558 100644
--- a/Eigen/src/Core/arch/CUDA/PacketMathHalf.h
+++ b/Eigen/src/Core/arch/CUDA/PacketMathHalf.h
@@ -226,10 +226,12 @@ template<> EIGEN_DEVICE_FUNC inline half2 pabs<half2>(const half2& a) {
 
 EIGEN_DEVICE_FUNC inline void
 ptranspose(PacketBlock<half2,2>& kernel) {
-  assert(false && "tbd");
-  //  half tmp = kernel.packet[0].y;
-  //  kernel.packet[0].y = kernel.packet[1].x;
-  //  kernel.packet[1].x = tmp;
+  half a1 = __low2half(kernel.packet[0]);
+  half a2 = __high2half(kernel.packet[0]);
+  half b1 = __low2half(kernel.packet[1]);
+  half b2 = __high2half(kernel.packet[1]);
+  kernel.packet[0] = __halves2half2(a1, b1);
+  kernel.packet[1] = __halves2half2(a2, b2);
 }
 
 } // end namespace internal