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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32 | if ( index < 0 || index >4 ) throw(AipsError("Stokes index out of range")); |
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33 | Vector<Float> out; |
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34 | Float phase = getTotalPhase(); |
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35 | Vector<Float> q(getSpectrum(0) - getSpectrum(1)); |
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36 | if ( nspec() == 4 ) { |
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37 | switch(index) { |
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38 | case 0: |
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39 | out = Vector<Float>(getSpectrum(0) + getSpectrum(1)); |
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40 | break; |
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41 | case 1: |
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42 | out = Vector<Float>(q * cos(phase) - Float(2.0)*getSpectrum(2) * sin(phase)); |
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43 | break; |
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44 | case 2: |
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45 | out = Vector<Float>(q * sin(phase) + Float(2.0)*getSpectrum(2) * cos(phase)); |
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46 | break; |
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47 | case 3: |
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48 | out = getFeedHand() * Float(2.0) * Vector<Float>(getSpectrum(3)); |
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49 | break; |
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50 | } |
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51 | } |
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52 | return out; |
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53 | } |
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54 | |
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55 | Vector<Float> asap::STPolLinear::getLinPol( uInt index ) |
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56 | { |
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57 | if ( index < 0 || index >4 ) throw(AipsError("LinPol index out of range")); |
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58 | Vector<Float> out,q,u; |
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59 | if ( nspec() == 4) { |
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60 | switch(index) { |
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61 | case 1: |
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62 | q = getStokes(1); |
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63 | u = getStokes(2); |
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64 | out = Vector<Float>(sqrt(pow(q,Float(2.0))+pow(u, Float(2.0)))); |
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65 | break; |
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66 | case 2: |
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67 | q = getStokes(1); |
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68 | u = getStokes(2); |
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69 | out = Vector<Float>(Float(180.0/C::pi/2.0) * atan2(u,q)); |
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70 | break; |
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71 | default: |
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72 | out = getStokes(index); |
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73 | } |
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74 | } |
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75 | return out; |
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76 | } |
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77 | |
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78 | Vector<Float> asap::STPolLinear::getLinear(uInt index ) |
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79 | { |
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80 | return getSpectrum(index); |
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81 | } |
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82 | |
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83 | Vector<Float> asap::STPolLinear::getCircular(uInt index ) |
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84 | { |
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85 | // convert to stokes I/ V first |
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86 | // |
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87 | // We use the convention |
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88 | // I = (RR+LL) // definition changed |
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89 | |
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90 | if ( index == 2 || index ==3 ) throw(AipsError("Re/Imag RL not implemented")); |
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91 | Vector<Float> I,V,out; |
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92 | I = getStokes(0); |
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93 | V = getStokes(3); |
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94 | switch(index) { |
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95 | case 0: |
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96 | out = (I + V)/Float(2.0); |
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97 | break; |
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98 | case 1: |
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99 | out = (I - V)/Float(2.0); |
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100 | break; |
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101 | default: |
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102 | out = Vector<Float>(); |
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103 | } |
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104 | return out; |
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105 | } |
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106 | |
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107 | void asap::STPolLinear::rotatePhase( Float phase ) |
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108 | { |
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109 | if (nspec() != 4) { |
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110 | throw(AipsError("You must have 4 linear polarizations to run this function")); |
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111 | } |
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112 | Float cosVal = cos(C::pi/180.0*phase); |
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113 | Float sinVal = sin(C::pi/180.0*phase); |
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114 | Matrix<Float>& specs = getSpectra(); |
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115 | Vector<Float> R2 = specs.column(2)*cosVal - specs.column(3)*sinVal; |
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116 | specs.column(3) = specs.column(2)*sinVal + specs.column(3)*cosVal; |
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117 | specs.column(2) = R2; |
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118 | } |
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119 | |
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120 | void asap::STPolLinear::invertPhase( Float phase ) |
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121 | { |
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122 | // phase isnt used, just ro keep interface the same for all pol operations |
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123 | Matrix<Float>& specs = getSpectra(); |
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124 | Vector<Float> I = specs.column(3); |
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125 | I *= Float(-1.0); |
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126 | } |
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127 | |
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128 | void asap::STPolLinear::rotateLinPolPhase( casa::Float phase ) |
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129 | { |
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130 | // |
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131 | // Rotate P = Q + iU but do it directly on the linear |
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132 | // correlations. |
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133 | // |
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134 | // We are using I=(XX+YY)/2 convention |
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135 | // C1 = XX; C2 = YY, C3 = Real(XY) |
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136 | // |
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137 | Vector<Float> I,Q,U; |
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138 | I = getStokes(0); |
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139 | Q = getStokes(1); |
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140 | U = getStokes(2); |
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141 | // Rotate Q & U (factor of 2 for polarization) |
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142 | Float cosVal = cos(C::pi/180.0*2.0*phase); |
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143 | Float sinVal = sin(C::pi/180.0*2.0*phase); |
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144 | Vector<Float> Q2 = Q*cosVal - U*sinVal; |
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145 | U = Q*sinVal + U*cosVal; |
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146 | Q = Q2; |
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147 | Matrix<Float>& specs = getSpectra(); |
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148 | specs.column(0) = (I+Q)/Float(2.0); |
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149 | specs.column(1) = (I-Q)/Float(2.0); |
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150 | specs.column(2) = U/Float(2.0); |
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151 | |
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152 | } |
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153 | |
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154 | } |
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