void version4(CArray& A, CArray& B, int nIters)
{
Timer timer;
struct cmplx {
double re, im;
};
cmplx* a = (cmplx*)A.data();
cmplx* b = (cmplx*)B.data();
setup(A,B);
int N = A.extent(firstDim);
timer.start();
for (int i=0; i < nIters; ++i)
{
for (int j=0; j < N; ++j)
{
double ar = a[j].re;
double ai = a[j].im;
b[j].re += ar*ar - ai*ai;
b[j].im += 2 * ar * ai;
}
}
timer.stop();
cout << "Time using really low-level version: " << timer.elapsedSeconds()
<< endl;
}
void version3(CArray& A, CArray& B, int nIters)
{
Timer timer;
int N = A.extent(firstDim);
// Low-level implementation
setup(A,B);
timer.start();
for (int i=0; i < nIters; ++i)
{
for (int j=0; j < N; ++j)
B(j) += A(j) * A(j);
}
timer.stop();
cout << "Time using low-level version: " << timer.elapsedSeconds()
<< endl;
}
