StokesVector and MuellerMatrix Improvements

* Add StokesVector constructor from polarization angle and efficiency
* Add MuellerMatrix construct from StokesVector components
* Add MuellerMatrix.from_vector method for populating an existing MuellerMatrix
  from a StokesVector
* Use these features in MapBinner and MapMockObserver

maps/include/maps/G3SkyMap.h

@@ -241,6 +241,9 @@ class StokesVector {
 	// you initialize one of these statically and then use it in arithmetic.
 	StokesVector() : t(backing[0]), q(backing[1]), u(backing[2]) {}
 
+	// Constructor for polarization coupling
+	StokesVector(double pol_ang, double pol_eff);
+
 	double &t, &q, &u;
 
 	StokesVector &operator +=(const StokesVector &r) {
@@ -292,8 +295,19 @@ class MuellerMatrix {
 	MuellerMatrix() : tt(backing[0]), tq(backing[1]),
 	    tu(backing[2]), qq(backing[3]), qu(backing[4]), uu(backing[5]) {}
 
+	// Constructor from Stokes vector
+	MuellerMatrix(const StokesVector &r) : tt(backing[0]), tq(backing[1]),
+	    tu(backing[2]), qq(backing[3]), qu(backing[4]), uu(backing[5]) {
+		from_vector(r);
+	}
+
 	double &tt, &tq, &tu, &qq, &qu, &uu;
 
+	void from_vector(const StokesVector &r) {
+		tt = r.t * r.t; tq = r.t * r.q; tu = r.t * r.u;
+		qq = r.q * r.q; qu = r.q * r.u; uu = r.u * r.u;
+	}
+
 	MuellerMatrix &operator +=(const MuellerMatrix &r) {
 		tt += r.tt; tq += r.tq; tu += r.tu;
 		qq += r.qq; qu += r.qu; uu += r.uu;

maps/src/G3SkyMap.cxx

@@ -1240,6 +1240,22 @@ double MuellerMatrix::Cond() const
 	return c;
 }
 
+StokesVector::StokesVector(double pol_ang, double pol_eff) :
+    t(backing[0]), q(backing[1]), u(backing[2])
+{
+	double phi = pol_ang / G3Units::rad * 2.0;
+	double gamma = pol_eff / (2.0 - pol_eff);
+
+	t = 1.0;
+	q = cos(phi) * gamma;
+	u = sin(phi) * gamma;
+
+	if (fabs(q) < 1e-12)
+		q = 0.0;
+	if (fabs(u) < 1e-12)
+		u = 0.0;
+}
+
 StokesVector & StokesVector::operator /=(const MuellerMatrix &r)
 {
 	MuellerMatrix ir = r.Inv();

maps/src/MapBinner.cxx

@@ -335,35 +335,6 @@ MapBinner::Process(G3FramePtr frame, std::deque<G3FramePtr> &out)
 	out.push_back(frame);
 }
 
-// Following two utility functions copied from the old map-maker and need to
-// be re-tooled -- either moved into the constructors of the relevant objects
-// and/or improved to handle things like boresight rotation.
-static void
-fill_mueller_matrix_from_stokes_coupling(
-    const StokesVector &stokes_coupling, MuellerMatrix &pcm)
-{
-	pcm.tt = stokes_coupling.t * stokes_coupling.t;
-	pcm.tq = stokes_coupling.t * stokes_coupling.q;
-	pcm.tu = stokes_coupling.t * stokes_coupling.u;
-	pcm.qq = stokes_coupling.q * stokes_coupling.q;
-	pcm.qu = stokes_coupling.q * stokes_coupling.u;
-	pcm.uu = stokes_coupling.u * stokes_coupling.u;
-}
-
-static void
-set_stokes_coupling(double pol_ang, double pol_eff,
-    StokesVector &stokes_coupling)
-{
-	stokes_coupling.t = 1.0;
-	stokes_coupling.q = cos(pol_ang/G3Units::rad *2.)*pol_eff/(2.0-pol_eff);
-	stokes_coupling.u = sin(pol_ang/G3Units::rad *2.)*pol_eff/(2.0-pol_eff);
-
-	if (fabs(stokes_coupling.q) < 1e-12)
-		stokes_coupling.q = 0;
-	if (fabs(stokes_coupling.u) < 1e-12)
-		stokes_coupling.u = 0;
-}
-
 void
 MapBinner::BinTimestream(const G3Timestream &det, double weight,
     const BolometerProperties &bp, const G3VectorQuat &pointing,
@@ -382,12 +353,11 @@ MapBinner::BinTimestream(const G3Timestream &det, double weight,
 		// And polarization coupling
 		// XXX: does not handle focal-plane rotation, since it assumes
 		// polarization coupling is constant for the whole scan.
-		StokesVector pcoupling;
-		set_stokes_coupling(bp.pol_angle, bp.pol_efficiency, pcoupling);
+		StokesVector pcoupling(bp.pol_angle, bp.pol_efficiency);
 
 		MuellerMatrix mueller;
 		if (W) {
-			fill_mueller_matrix_from_stokes_coupling(pcoupling, mueller);
+			mueller.from_vector(pcoupling);
 			mueller *= weight;
 		}
 

maps/src/MapMockObserver.cxx

@@ -34,6 +34,7 @@ class MapMockObserver : public G3Module {
 
 	bool interp_;
 	bool error_on_zero_;
+	int pol_sign_;
 
 	SET_LOGGER("MapMockObserver");
 };
@@ -109,26 +110,12 @@ MapMockObserver::MapMockObserver(std::string pointing, std::string timestreams,
 {
 	if ((Q_ && !U_) || (U_ && !Q_))
 		log_fatal("If simulating polarized maps, pass both Q and U.");
-}
-
-// Following utility function copied from old map-maker and needs re-tooling
-// to handle boresight rotation.
-static void
-set_stokes_coupling(double pol_ang, double pol_eff,
-    StokesVector &stokes_coupling, G3SkyMap::MapPolConv pol_conv)
-{
-	stokes_coupling.t = 1.0;
-	stokes_coupling.q = cos(pol_ang/G3Units::rad *2.)*pol_eff/(2.0-pol_eff);
-	stokes_coupling.u = sin(pol_ang/G3Units::rad *2.)*pol_eff/(2.0-pol_eff);
-	if (pol_conv == G3SkyMap::COSMO)
-		stokes_coupling.u *= -1.0;
-	else if (pol_conv == G3SkyMap::ConvNone)
-		log_fatal("Missing pol_conv");
 
-	if (fabs(stokes_coupling.q) < 1e-12)
-		stokes_coupling.q = 0;
-	if (fabs(stokes_coupling.u) < 1e-12)
-		stokes_coupling.u = 0;
+	if (U_) {
+		if (U_->GetPolConv() == G3SkyMap::ConvNone)
+			log_fatal("Missing pol_conv");
+		pol_sign_ = (U_->GetPolConv() == G3SkyMap::COSMO) ? -1 : 1;
+	}
 }
 
 void
@@ -210,9 +197,8 @@ MapMockObserver::Process(G3FramePtr frame, std::deque<G3FramePtr> &out)
 			detpointing = T_->AnglesToPixels(alpha, delta);
 
 		if (Q_) {
-			StokesVector pcoupling;
-			set_stokes_coupling(bp.pol_angle, bp.pol_efficiency,
-			    pcoupling, U_->GetPolConv());
+			// needs re-tooling to handle boresight rotation.
+			StokesVector pcoupling(bp.pol_angle * pol_sign_, bp.pol_efficiency);
 			for (size_t i = 0; i < det.size(); i++) {
 				if (interp_) {
 					std::vector<size_t> pixels;