Introduction

In this section, let us explain how to apply the library without parallelization.
A program that uses the library "staggex.h" consists of four parts (example see here ):

1. The first part is the heading. One has to include:

   #include "source/staggex.h"

2. In the second part, one has to define a non-staggered grid on a hexahedron.

   For example, this can be done in the following way:

     int Nx, Ny, Nz;

            ...
        D3vector vWSD(0.0,0.0,0.0);
        D3vector vENT(1.0,1.0,1.0));
        Grid grid(Nx,Ny,Nz,vSWD,vNET);

Here, vSWD and vENT are the corner points of the hexahedron and Nx+1, Ny+1, Nz+1 are the numbers of grid points in x-, y-, and z-direction.

3. A variable is vector of a certain type on a grid. This variable can be staggered in x-,y- and z-direction. For example, a variable on a completely non-staggered grid is defined as follows:

     Variable<double,not_staggered,not_staggered,not_staggered> u(grid);

and a variable in a staggered grid in x-, y-, z-direction is defined as follows:

   Variable<double,staggered,staggered,staggered> v(grid); 

A variable on a staggered grid in x-, y-, z-direction is a cell variable.

4. After defining variables, one can implement numerical codes. For example, after

     Coordinate<WE_dir,Grid_uniform_one_d> X(grid);

        u = X;

  w = 2.2;
  u = u + w;

the vector represented by u contains the value x+2.2 at every grid point, where x is the x-coordinate of each grid point.

Last modified: Wed Jun 6 10:15:36 PDT 2001