From a programmer view, their implementation is similar , but from CAE user view to solve Partial diff equations(PDE), initial values and body source are distinct things.
https://fenicsproject.org/pub/tutorial/ ... t1003.html
Body source is the `f(x)` item in equation 1, it has different unit as x, so it is different quantity. Body source does not appear in linear elasticity PDE, but for dynamic problem there is, that is gravity. For heat transfer problem, that is heat source. Gravity applies to whole domain, but other source may only apply to a portion of geometry/domain. That is why, a taskpanel like FemMaterial that can select CAD solids are needed, but can be default to the whole domain.
Initial value is `x` at zero condition for unsteady sytem/temporal problem (for unsteady problem it is a kind of PDE constraint).or a better x value to start solver the `Ax=b`, for steady problem of nonlinear system, a better x initial value can converge, while a worse one will diverge. so in CFD, initial value is an essential input, in contrast to linear elasticity FEM, initial value of `x` is not necessary.
That is why two toolcon/gui/viewproviders are needed, to avoid confusing users. Under the GUI, code should be reused to avoid duplication and help maintenance.
bernd wrote: ↑
Thu Feb 20, 2020 7:55 am
a general question ...
What is the difference between a constraint "initial value" and a constraint "body source" ?
Manly the constraint "body source" I do not understand what it is for? According its implementation to could be a initial value too.