  The computation of Lagrangian coherent structures (LCS) has become a standard
tool for the analysis of advective transport in unsteady flow applications. LCS
identification is primarily accomplished by evaluating measures based on the
finite-time Cauchy Green (CG) strain tensor over the fluid domain. Sampling the
CG tensor requires the advection of large numbers of fluid tracers, which can
be computationally intensive, but presents a large degree of data parallelism.
Processing can be specialized to parallel computing architectures, but on the
other hand, there is compelling need for robust and flexible implementations
for end users. Specifically, code that can accommodate analysis of wide-ranging
fluid mechanics applications, while using a modular structure that is easily
extended or modified, and facilitates visualization is desirable. We discuss
the use of Visualization Toolkit (VTK) libraries as a foundation for
object-oriented LCS computation, and how this framework can facilitate
integration of LCS computation into flow visualization software such as
ParaView. We also discuss the development of CUDA GPU kernels for efficient
parallel spatial sampling of the flow map, including optimizing these kernels
for better utilization.
