The library source code mainly resides in the tpie/ directory. See File list.
The test/ directory contains test code. test/unit/ contains source code for unit tests used by CTest, and test/speed_regression/ contains programs for measuring TPIE performance.
The cpp0xtest/ directory contains code that might not compile on all modern compilers. CMake uses this to determine if the system compiler supports variadic templates and rvalues.
The example/ directory contains a simple example of how to use TPIE in your application, this includes a small CMakeLists.txt example.