Fast simulation of X-ray diffraction patterns from cellulose fibrils using GPUs

Cellulose in maize is an ideal candidate for a sustainable and renewable energy source because of its global abundance. X-ray scattering has been used as an experimental technique to study cellulose fibrils during processing. In order to understand the impact of chemical or physical treatments on structural parameters such as diameter, twist and coiling, we are simulating X-ray scattering from large bundles of cellulose. Because the structure of these fibrils is non-periodic, these calculations are computationally intensive. In this paper, we describe a GPU-based molecular scattering algorithm developed to calculate X-ray scattering intensity from molecular models of cellulose fibrils. The implementation on Graphics Processing Units (GPUs) greatly accelerates the calculation compared to an optimized CPU program, enabling the assessment of hundreds of models for the cellulose fibril structure.