if (f == j)
{ // either first of complex conjugate pair or real
if (isComplex[f])
{
return new ComplexNumber(data[idx], data[idx + n]);
}
else
{
return new ComplexNumber(data[idx], 0.0d);
}
}
else
{
return new ComplexNumber(data[idx], -data[idx + n]);
}
}