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#include <blitz/array.h>
#include <blitz/timer.h>
BZ_USING_NAMESPACE(blitz)
BZ_DECLARE_STENCIL4(acoustic2D_stencil,P1,P2,P3,c)
P3 = 2 * P2 + c * Laplacian2D(P2) - P1;
BZ_END_STENCIL
int benchmark(int N, int nIterations, int blockSize)
{
Array<float,2> P1, P2, P3, c;
allocateArrays(shape(N,N), P1, P2, P3, c);
// Initial conditions: obviously in a real application these
// wouldn't be zeroed...
Range I(0,blockSize-1), J(0,blockSize-1);
P1(I,J) = 0;
P2(I,J) = 0;
P3(I,J) = 0;
c(I,J) = 0;
for (int i=0; i < nIterations; ++i)
{
// Apply the stencil object to the arrays
applyStencil(acoustic2D_stencil(), P1(I,J), P2(I,J), P3(I,J), c(I,J));
// Set [P1,P2,P3] <- [P2,P3,P1] to set up for the next
// time step
cycleArrays(P1,P2,P3);
}
return 0;
}
int main()
{
Timer timer;
cout << "N\tMflops" << endl;
const int blockSize = 27;
for (int N=2000; N < 2100; ++N)
{
double stencilPoints = pow(blockSize-2,2.0);
int nIterations = 5000;
timer.start();
benchmark(N, nIterations, blockSize);
timer.stop();
double flops = (4 + 7) * stencilPoints * nIterations;
double Mflops = flops / timer.elapsedSeconds() / 1.0E+6;
cout << N << "\t" << Mflops << endl;
}
return 0;
}
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