1. Project
It is also possible to make projections with the library using the keywords project() or on()
Interface:
  project( _range, _space, _expr, _geomap );
Required parameters:
- 
_space: the space in which lives the projected expression, it should be a nodal function space - 
_expr: the expression to project 
Optional parameters:
- 
_range: the domain for the projection.- 
Default = all elements from
space→mesh() 
 - 
 - 
_geomap: type of geometric mapping.- 
Default =
GEOMAP_OPT 
 - 
 
Example:
From doc/manual/laplacian/laplacian.cpp
  element_type e( Xh, "e" );
  e = project( _space = Xh,
               _range = elements( mesh ),
               _expr = g );
From doc/manual/heatns/convection_run.cpp
tn = project( _space = Xh->functionSpace<2>(),
              _range = elements( mesh ),
              _expr = constant( 300 ) );