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compose(3rheolef) rheolef compose(3rheolef)


compose - n-ary function application in expressions (rheolef-7.2)


template <class Function, class... Expressions>
Expression compose (const Function& f, const Expressions&... exprs);


Compose a n-ary function f with n fields in interpolate(3) and integrate(3) nonlinear expressions.


The compose operator is used for applying a user-provided function to a field:

Float f (Float u) { return 1/u + sqrt(u); }
field vh = interpolate (Xh, compose(f, uh));

When two arguments are involved:

Float g (Float u, Float v) { return v/u + sqrt(u*v); }
field wh = interpolate (Xh, compose(g, uh, vh));

The compose operator supports general n-ary functions and class-functions.


The compose function supports also the method of characteristic(2) used e.g. for convection-diffusion problems:

characteristic X (-delta_t*uh);
test v (Xh);
field lh = integrate (compose(uh,X)*v);


This documentation has been generated from file main/lib/compose.h


Pierre Saramito <>


Copyright (C) 2000-2018 Pierre Saramito <> GPLv3+: GNU GPL version 3 or later <>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

Thu Jul 14 2022 Version 7.2