[904] | 1 | // |
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| 2 | // C++ Implementation: STPolLinear |
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| 3 | // |
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| 4 | // Description: |
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| 5 | // |
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| 6 | // |
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| 7 | // Author: Malte Marquarding <Malte.Marquarding@csiro.au>, (C) 2006 |
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| 8 | // |
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| 9 | // Copyright: See COPYING file that comes with this distribution |
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| 10 | // |
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| 11 | // |
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| 12 | |
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| 13 | #include <casa/Arrays/ArrayMath.h> |
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| 14 | #include <casa/BasicMath/Math.h> |
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| 15 | #include <casa/Exceptions/Error.h> |
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| 16 | #include <casa/BasicSL/Constants.h> |
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| 17 | #include "STPolLinear.h" |
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| 18 | |
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| 19 | using namespace casa; |
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| 20 | |
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| 21 | namespace asap { |
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| 22 | |
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| 23 | Factory<STPol,STPolLinear> STPolLinear::myFactory; |
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| 24 | |
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| 25 | STPolLinear::~STPolLinear() |
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| 26 | { |
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| 27 | } |
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| 28 | |
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| 29 | |
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| 30 | Vector<Float> asap::STPolLinear::getStokes( uint index ) |
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| 31 | { |
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[2163] | 32 | if ( index > 4 ) throw(AipsError("Stokes index out of range")); |
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[904] | 33 | Vector<Float> out; |
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[957] | 34 | Float phase = getTotalPhase(); |
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| 35 | Vector<Float> q(getSpectrum(0) - getSpectrum(1)); |
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[904] | 36 | if ( nspec() == 4 ) { |
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| 37 | switch(index) { |
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| 38 | case 0: |
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[957] | 39 | out = Vector<Float>(getSpectrum(0) + getSpectrum(1)); |
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[904] | 40 | break; |
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| 41 | case 1: |
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[1007] | 42 | out = Vector<Float>(q * cos(phase) - Float(2.0)*getSpectrum(2) * sin(phase)); |
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[904] | 43 | break; |
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[957] | 44 | case 2: |
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[1007] | 45 | out = Vector<Float>(q * sin(phase) + Float(2.0)*getSpectrum(2) * cos(phase)); |
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[957] | 46 | break; |
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| 47 | case 3: |
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[1007] | 48 | out = getFeedHand() * Float(2.0) * Vector<Float>(getSpectrum(3)); |
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[957] | 49 | break; |
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[904] | 50 | } |
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[1189] | 51 | } else if (nspec() == 2) { |
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| 52 | if ( index == 0 ) |
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| 53 | out = Vector<Float>(getSpectrum(0) + getSpectrum(1)); |
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[904] | 54 | } |
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| 55 | return out; |
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| 56 | } |
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| 57 | |
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| 58 | Vector<Float> asap::STPolLinear::getLinPol( uInt index ) |
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| 59 | { |
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[1189] | 60 | if (nspec() != 4) { |
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| 61 | throw(AipsError("You must have 4 linear polarizations to run this function")); |
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| 62 | } |
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[2163] | 63 | if ( index >4 ) throw(AipsError("LinPol index out of range")); |
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[957] | 64 | Vector<Float> out,q,u; |
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[904] | 65 | if ( nspec() == 4) { |
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| 66 | switch(index) { |
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| 67 | case 1: |
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[957] | 68 | q = getStokes(1); |
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| 69 | u = getStokes(2); |
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| 70 | out = Vector<Float>(sqrt(pow(q,Float(2.0))+pow(u, Float(2.0)))); |
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[904] | 71 | break; |
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| 72 | case 2: |
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[965] | 73 | q = getStokes(1); |
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[957] | 74 | u = getStokes(2); |
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| 75 | out = Vector<Float>(Float(180.0/C::pi/2.0) * atan2(u,q)); |
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[904] | 76 | break; |
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| 77 | default: |
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| 78 | out = getStokes(index); |
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| 79 | } |
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| 80 | } |
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| 81 | return out; |
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| 82 | } |
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| 83 | |
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| 84 | Vector<Float> asap::STPolLinear::getLinear(uInt index ) |
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| 85 | { |
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| 86 | return getSpectrum(index); |
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| 87 | } |
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| 88 | |
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| 89 | Vector<Float> asap::STPolLinear::getCircular(uInt index ) |
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| 90 | { |
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| 91 | // convert to stokes I/ V first |
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| 92 | // |
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| 93 | // We use the convention |
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| 94 | // I = (RR+LL) // definition changed |
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[1189] | 95 | if (nspec() != 4) { |
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| 96 | throw(AipsError("You must have 4 linear polarizations to run this function")); |
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| 97 | } |
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[904] | 98 | if ( index == 2 || index ==3 ) throw(AipsError("Re/Imag RL not implemented")); |
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| 99 | Vector<Float> I,V,out; |
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| 100 | I = getStokes(0); |
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| 101 | V = getStokes(3); |
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| 102 | switch(index) { |
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| 103 | case 0: |
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[1007] | 104 | out = (I + V)/Float(2.0); |
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[904] | 105 | break; |
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| 106 | case 1: |
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[1007] | 107 | out = (I - V)/Float(2.0); |
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[904] | 108 | break; |
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| 109 | default: |
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| 110 | out = Vector<Float>(); |
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| 111 | } |
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| 112 | return out; |
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| 113 | } |
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| 114 | |
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| 115 | void asap::STPolLinear::rotatePhase( Float phase ) |
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| 116 | { |
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| 117 | if (nspec() != 4) { |
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| 118 | throw(AipsError("You must have 4 linear polarizations to run this function")); |
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| 119 | } |
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| 120 | Float cosVal = cos(C::pi/180.0*phase); |
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| 121 | Float sinVal = sin(C::pi/180.0*phase); |
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| 122 | Matrix<Float>& specs = getSpectra(); |
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| 123 | Vector<Float> R2 = specs.column(2)*cosVal - specs.column(3)*sinVal; |
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| 124 | specs.column(3) = specs.column(2)*sinVal + specs.column(3)*cosVal; |
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| 125 | specs.column(2) = R2; |
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| 126 | } |
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| 127 | |
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| 128 | void asap::STPolLinear::invertPhase( Float phase ) |
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| 129 | { |
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| 130 | // phase isnt used, just ro keep interface the same for all pol operations |
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[2163] | 131 | (void) phase; |
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[1189] | 132 | if (nspec() != 4) { |
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| 133 | throw(AipsError("You must have 4 linear polarizations to run this function")); |
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| 134 | } |
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[904] | 135 | Matrix<Float>& specs = getSpectra(); |
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| 136 | Vector<Float> I = specs.column(3); |
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| 137 | I *= Float(-1.0); |
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| 138 | } |
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| 139 | |
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[911] | 140 | void asap::STPolLinear::rotateLinPolPhase( casa::Float phase ) |
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| 141 | { |
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| 142 | // |
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| 143 | // Rotate P = Q + iU but do it directly on the linear |
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| 144 | // correlations. |
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| 145 | // |
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| 146 | // We are using I=(XX+YY)/2 convention |
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| 147 | // C1 = XX; C2 = YY, C3 = Real(XY) |
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| 148 | // |
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[1189] | 149 | if (nspec() != 4) { |
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| 150 | throw(AipsError("You must have 4 linear polarizations to run this function")); |
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| 151 | } |
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[911] | 152 | Vector<Float> I,Q,U; |
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| 153 | I = getStokes(0); |
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| 154 | Q = getStokes(1); |
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| 155 | U = getStokes(2); |
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| 156 | // Rotate Q & U (factor of 2 for polarization) |
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| 157 | Float cosVal = cos(C::pi/180.0*2.0*phase); |
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| 158 | Float sinVal = sin(C::pi/180.0*2.0*phase); |
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| 159 | Vector<Float> Q2 = Q*cosVal - U*sinVal; |
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| 160 | U = Q*sinVal + U*cosVal; |
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| 161 | Q = Q2; |
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| 162 | Matrix<Float>& specs = getSpectra(); |
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[1007] | 163 | specs.column(0) = (I+Q)/Float(2.0); |
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| 164 | specs.column(1) = (I-Q)/Float(2.0); |
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| 165 | specs.column(2) = U/Float(2.0); |
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[911] | 166 | |
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[904] | 167 | } |
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[911] | 168 | |
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| 169 | } |
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