questions about NeumannBC

[q769855234]

now suppose I have x,y,t as inputs,u,v,p as outputs ,how can I express dp/dx=0 and dp/dy=0 with NeumannBC

[lululxvi]

This is not Neumann BC. Neumann BC is du/dn https://en.wikipedia.org/wiki/Neumann_boundary_condition. Use OperatorBC, see https://deepxde.readthedocs.io/en/latest/modules/deepxde.icbc.html#deepxde.icbc.boundary_conditions.OperatorBC and FAQ "Q: More details and examples about boundary conditions."

[q769855234]

This is not Neumann BC. Neumann BC is du/dn https://en.wikipedia.org/wiki/Neumann_boundary_condition. Use OperatorBC, see https://deepxde.readthedocs.io/en/latest/modules/deepxde.icbc.html#deepxde.icbc.boundary_conditions.OperatorBC and FAQ "Q: More details and examples about boundary conditions."

the Beumann boundary condition specifies the values of the derivative applied at the boundary,this is just dp/dx and dp/dy，why is it incorrect? And I cannot understand the operator BC

[q769855234]

This is not Neumann BC. Neumann BC is du/dn https://en.wikipedia.org/wiki/Neumann_boundary_condition. Use OperatorBC, see https://deepxde.readthedocs.io/en/latest/modules/deepxde.icbc.html#deepxde.icbc.boundary_conditions.OperatorBC and FAQ "Q: More details and examples about boundary conditions."

Is there any examples about operatorBC?

[lululxvi]

Neumann BC is NOT the condition of partial derivative. It is the condition for the normal derivative.

See the examples at FAQ "Q: More details and examples about boundary conditions."