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# Coefficient functions

Coefficient functions are defined as list of constants or functions. Each element corresponds to a sub-domain, or a part of the boundary (specified by the boundary condition number).

    define coefficient coef_lam  10,15, -5, (5*x), (sin(y)),

- Functions must be put into brackets. Function may be built as described in Section 3.1, but may now additionally contain variables.
- Predefined variables are , , and for the Cartesian coordinates.
- Specifying too many coefficients is ok, too less will lead to an error.

Coefficients can be specified by materials. Use the '-material' flag for CSG geometries.

    define coefficient coef_nu material
            iron 10000
            air  1
            default 1

All subdomains consisting of material 'iron' get the constant coefficient 10000, the 'air' domain as well as all others get 1.