Smart Tessellated Look-up Tables for Nuclear Femtography

Deep Virtual Exclusive Scattering enables construction of spatial images of the quarks and gluons in atomic nuclei. The complexity of these reactions necessitates extensive simulations of the functional behavior of the cross-section. The cross-section can be parameterized by a set of functions called Compton Form Factors (CFFs). In the absence of ab-initio calculations of CFFs from QCD, we must rely on models of experimental data. The computational cost of calculating CFFs can be reduced by interpolating on lookup tables. We utilize the ODU Center for Real-Time Computing software to create a tessellated database of CFFs. Unstructured tessellations provide a discretization of the phase-space using irregular simplices. Tessellations are able to capture the non-uniform characteristics of the functions by concentrating more points in areas that require higher granularity, while still creating fewer number of vertices overall. An iterative adaptivity algorithm was designed to efficiently refine the tessellations to ensure interpolation error is minimized. These utilities provide a flexibility for any model; greatly reducing computation requirements and increasing data portability while maintaining an rms error ~1% between interpolation and model.