void Pulsar::BackendCorrection::operator () (Archive* arch) const try
{
Backend* backend = arch->get<Backend>();
if (!backend || backend->get_corrected())
return;
Signal::State state = arch->get_state();
Signal::Basis basis = arch->get_basis();
Signal::Hand hand = backend->get_hand();
Signal::Argument argument = backend->get_argument();
bool correct_lsb = must_correct_lsb (backend, arch);
if (Archive::verbose > 2)
cerr << "Pulsar::BackendCorrection::operator basis=" << basis
<< " hand=" << hand << " phase=" << argument
<< " lsb=" << correct_lsb << endl;
/*
complex conjugation due to lower sideband downconversion and
backend convention have the same effect; the following lines
effect an exclusive or operation.
*/
if (correct_lsb)
{
if (Archive::verbose > 2)
cerr << "Pulsar::BackendCorrection::operator down conversion" << endl;
if (argument == Signal::Conjugate)
argument = Signal::Conventional;
else
argument = Signal::Conjugate;
}
unsigned npol = arch->get_npol();
if (npol < 2)
return;
bool swap01 = false;
bool flip[4] = { false, false, false, false };
if (npol == 4)
{
if (argument == Signal::Conjugate)
{
if (Archive::verbose > 2)
cerr << "Pulsar::BackendCorrection::operator phase convention" << endl;
if (state == Signal::Stokes && basis == Signal::Circular)
flip[2] = !flip[2]; // Flip Stokes U
else
flip[3] = !flip[3]; // Flip Stokes V or Im[AB]
}
if (hand == Signal::Left)
{
if (Archive::verbose > 2)
cerr << "Pulsar::BackendCorrection::operator hand" << endl;
if (state == Signal::Stokes && basis == Signal::Circular)
flip[2] = !flip[2]; // Flip Stokes U and ...
else if (state == Signal::Stokes && basis == Signal::Linear)
flip[1] = !flip[1]; // Flip Stokes Q and ...
else if (state == Signal::PseudoStokes)
flip[1] = !flip[1]; // Flip AA-BB and ...
flip[3] = !flip[3]; // Flip Stokes V or Im[AB]
}
}
// If state == Coherence or PPQQ ...
if (hand == Signal::Left &&
(state == Signal::Coherence || state == Signal::PPQQ))
swap01 = true;
bool flip_something = false;
for (unsigned ipol=0; ipol < npol; ipol++)
if (flip[ipol])
{
if (Archive::verbose > 2)
cerr << "Pulsar::BackendCorrection::operator flip " << ipol << endl;
flip_something = true;
}
if (swap01 && Archive::verbose > 2)
cerr << "Pulsar::BackendCorrection::operator swap 0 and 1" << endl;
if (flip_something || swap01)
{
for (unsigned isub=0; isub < arch->get_nsubint(); isub++)
{
Integration* integration = arch->get_Integration(isub);
for (unsigned ichan=0; ichan < arch->get_nchan(); ichan++)
{
for (unsigned ipol=0; ipol < npol; ipol++)
if (flip[ipol])
integration->get_Profile(ipol, ichan)->scale(-1);
if (swap01)
integration->expert()->swap_profiles(0, ichan, 1, ichan);
}
}
}
backend->set_corrected ();
}
catch (Error& error)
{
throw error += "Pulsar::BackendCorrection::operator";
}
