DESCRIPTION

 The function interpolation implements the
 Lagrange interpolation of a function or a class-function.

SYNOPSYS

 template <class Function>
 field interpolate (const space& Xh, const Function& f);

EXAMPLE

 The following code compute the Lagrange interpolation
 pi_h_u of u(x).

  Float u(const point& x);
  ...
  geo omega("square");
  space Xh (omega, "P1");
  field pi_h_u = interpolate (Xh, u);

ADVANCED EXAMPLE

It is possible the replace the function u by a variable of the field type that represents a picewise polynomial function: this invocation allows the reinterpolation of a field on another mesh or with another approximation.

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