NAME

       interpolate - function or expression interpolation (rheolef-7.2)

DESCRIPTION

       The interpolation function implements the usual Lagrange interpolation of a function or a
       class-function on a finite element space(2).

SYNOPSIS

           template <class Expression>
           field interpolate (const space& Xh, const Expression& expr);

        Example The following code compute the Lagrange interpolation pi_h_u the function u(x):

          Float u(const point& x) { return exp(x[0]*x[1]); }
          ...
          geo omega("square");
          space Xh (omega, "P1");
          field pi_h_u = interpolate (Xh, u);

EXPRESSIONS

       It is possible to interpolate an expression involving a combination of functions, class-
       functions and fields:

           field vh = interpolate (Xh, sqrt(uh) + 2*max(0.,uh));

REINTERPOLATION

       The reinterpolation of a field on another mesh or on another finite element space is also
       possible:

           geo omega2 ("square2");
           space X2h (omega2, "P1");
           field uh2 = interpolate (X2h, pi_h_u);

        Such a reinterpolation is very frequent in mesh adaptive loops.

IMPLEMENTATION

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

       The implementation of expressions bases on the expression template and SFINAE C++ idioms.

AUTHOR

       Pierre  Saramito  <Pierre.Saramito@imag.fr>

COPYRIGHT

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