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#include <blitz/timer.h>
#include <iostream>
#include <fstream>
BZ_USING_NAMESPACE(blitz)
BZ_USING_NAMESPACE(std)
extern "C" {
void echo_f77tuned(int& N, int& niters, float& check, int& blockSize);
}
int main()
{
int N = 1024;
int niters = 48;
float check;
double Mflops = niters * 9;
Timer timer;
ofstream ofs("echotune.log");
cout << "This program decides on the best block size for a typical 2D "
<< endl << "stencil operation. Pick the block size which has the "
<< endl << "maximum Mflops/s." << endl << endl;
cout << "Block size\tMflops/s" << endl;
int blockSize;
for (blockSize=1; blockSize < 32; ++blockSize)
{
timer.start();
echo_f77tuned(N, niters, check, blockSize);
timer.stop();
cout << blockSize << "\t" << (Mflops/timer.elapsedSeconds()) << endl;
ofs << blockSize << "\t" << (Mflops/timer.elapsedSeconds()) << endl;
}
for (; blockSize < 1024; blockSize += 32)
{
timer.start();
echo_f77tuned(N, niters, check, blockSize);
timer.stop();
cout << blockSize << "\t" << (Mflops/timer.elapsedSeconds()) << endl;
ofs << blockSize << "\t" << (Mflops/timer.elapsedSeconds()) << endl;
}
return 0;
}
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