#include <blitz/array.h>#include <blitz/array/stencil-et.h>BZ_USING_NAMESPACE(blitz)// This example illustrates a simple use of stencils.// It applies a Laplacian operator to an array which is// all zero, except for a single 1 in the centre.// This results in the stencil pattern (although reversed// and upside-down).int main(){    const int N = 9;    // Create some arrays    Array<float,2> A(N,N), B(N,N), C(N,N), D(N,N);    // Initialize A to 1 in the centre, 0 elsewhere    A = 0;    A(N/2,N/2) = 1.0;    // Get the interior of the arrays.  Since central42 is the    // stencil [ 1 -4 6 -4 1 ], we have to leave a padding of 2    // cells around the interior.  The range 2..N-3 does this.    Range I(2,N-3);    Array<float,2> Ai = A(I,I), Bi = B(I,I), Ci = C(I,I), Di = D(I,I);    // These declarations let us call the first dimension "x"    // and the second dimension "y".    const int x = firstDim, y = secondDim;    // Apply the stencils.  Note that Laplacian2D is identical to    // central22(Ai,x) + central22(Ai,y).    Bi = Laplacian2D(Ai);    Ci = central42(Ai,x) + central42(Ai,y);    Di = central22(Ai,x) + central22(Ai,y);    // Display some of the results    Range middle(N/4,3*N/4);    cout << "Laplacian2D: " << B(middle,middle) << endl         << "central42: " << C(middle,middle) << endl         << "central22: " << D(middle,middle) << endl;    return 0;}