x is a variable Variable< ... , sx , sy , sz >
subgrid is a variable of type Variable<bool , sx , sy , sz > , and
Expr is an expression. Than, the statement
x = Expr | subgrid;
is evaluated at every grid point, where subgrid has the value true.
The values of variable subgrid can be set by any expression. However, there is a special construction to set the values of subgrid. Let
bool (*Marker_formula)(double x, double y, double z);
be a formula which marks a subgrid of the discretization grid. This means that Marker_formula returns the value true if and only if the point (x,y,z) is contained in the subgrid. Then, the construction
subgrid = Marker_formula;
sets the value true at all grid points of the marked subgrid.
Last modified: Fri Jun 1 11:41:25 PDT 2001