Foton and Diaggui both suffer from single precision issues on graphs
Even though representation of frequencies is by doubles in diaggui, the graphs show rounding issues: points are drawn on the graph constrained to values re presentable by single precision floating point. See attached pictures.
Keita also created a diaggui plot that made it explicit, with values at different frequency graphed on the same vertical line, the line corresponding with values representable by single point precision.
Edited by Erik von Reis