  Credibility building activities in computational research include
verification and validation, reproducibility and replication, and uncertainty
quantification. Though orthogonal to each other, they are related. This paper
presents validation and replication studies in electromagnetic excitations on
nanoscale structures, where the quantity of interest is the wavelength at which
resonance peaks occur. The study uses the open-source software PyGBe: a
boundary element solver with trecode acceleration and GPU capability. We
replicate a result by Rockstuhl et al. (2005, doi:10/dsxw9d) with a
two-dimensional boundary element method on silicon carbide particles, despite
differences in our method. The second replication case from Ellis et al. (2016,
doi:10/f83zcb) looks at aspect ratio effects on high-order modes of localized
surface phonon-polariton nanostructures. The results partially replicate: the
wavenumber position of some mode match, but for other modes they differ. With
virtually no information about the original simulations, explaining the
discrepancies is not possible. A comparison with experiments that measured
polarized reflectance of silicon carbide nano pillars provides a validation
case. The wavenumber of the dominant mode and two more do match, but
differences remain in other minor modes. Results in this paper were produced
with strict reproducibility practices, and we share reproducibility packages
for all, including input files, execution scripts, secondary data,
post-processing code and plotting scripts, and the figures (deposited in
Zenodo). In view of the many challenges faced, we propose that reproducible
practices make replication and validation more feasible.
