ILM Base libraries have following four libraries.
*Half is a class that encapsulates ILM’s 16-bit floating-point format.
*IlmThread is a thread abstraction library for use with OpenEXR
and other software packages.
*Imath implements 2D and 3D vectors, 3×3 and 4×4 matrices, quaternions
and other useful 2D and 3D math functions.
*Iex is an exception-handling library.