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Pde()

The syntax for pde is

pde(u) [+-] op1(u)[*/]exp1 [+-] op2(u)[*/]exp2...=exp3

It defines a partial differential equation with non constant coefficients where op is one of the operator:

and where [*/] means either a * or a / and similarly for $ \pm$. Note that the expressions are necessarily AFTER the operator while in practice they are between the 2 differentiations for laplace...dyy . Thus laplace(u)*(x+y) means

$ \nabla.((x+y)\nabla u)$

.Similarly dxy(u)*f means

$ \frac{\partial f \frac{\partial u}{\partial y}}{\partial x}$.



2001-11-04