UDFs can be compiled in Ansys Fluent with OpenCL support for execution on General Purpose Graphics Processing Units (GPGPUs) on lnamd64 and win64 platforms. To enable OpenCL support, you should use the following text user interface (TUI) command: /define/user-defined/enable-udf-on-gpu before compiling the UDF. The UDF library is linked with libOpenCL.so on lnamd64 and OpenCL.dll on win64. For execution on GPU systems, the appropriate environment variable (LD_LIBRARY_PATH on lnamd64 or %path% on win64) should be correctly set so that libOpenCL.so/OpenCL.dll is loaded along with the UDF library.