The design patterns likely to be most relevant to NEPTUNE are described in refs. [31, 33].
The PUPPETEER pattern appears to be exclusive to the works of Rouson et al, hence is described further here. It is directed towards the calculation of the Jacobian of multi-component systems typically needed for Newton-Raphson type solution of
update equations. The idea is that the puppeteer need only know which blocks of the Jacobian matrix are nonzero, although the puppets need to be capable of forming derivatives with respect to all state variables.
Figure 6.3: PUPPETEER pattern. Each puppet (‘Fluid 1’, ‘Fluid 2’, ‘Particles 1’) may include terms involving the other puppets. For example, suppose the puppet for ‘Fluid 1’ has terms involving also ‘Particles 1’
variables (but not ‘Fluid 2’), then the puppeteer can request derivatives of the puppet’s terms both with respect to ‘Fluid 1’ and ‘Particles 1’ variables, but knows not to ask for derivatives with respect to ‘Fluid 2’ variables.
