1 | //# Spectral2Estimate.cc: Member templates for SpectralEstimate
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2 | //# Copyright (C) 2001,2002,2003,2004
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3 | //# Associated Universities, Inc. Washington DC, USA.
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4 | //#
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5 | //# This library is free software; you can redistribute it and/or modify it
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6 | //# under the terms of the GNU Library General Public License as published by
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7 | //# the Free Software Foundation; either version 2 of the License, or (at your
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8 | //# option) any later version.
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9 | //#
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10 | //# This library is distributed in the hope that it will be useful, but WITHOUT
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11 | //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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12 | //# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
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13 | //# License for more details.
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14 | //#
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15 | //# You should have received a copy of the GNU Library General Public License
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16 | //# along with this library; if not, write to the Free Software Foundation,
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17 | //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
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18 | //#
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19 | //# Correspondence concerning AIPS++ should be addressed as follows:
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20 | //# casacore::Internet email: aips2-request@nrao.edu.
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21 | //# Postal address: AIPS++ Project Office
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22 | //# National Radio Astronomy Observatory
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23 | //# 520 Edgemont Road
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24 | //# Charlottesville, VA 22903-2475 USA
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25 | //#
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26 | //# $Id: Spectral2Estimate.tcc 21465 2014-06-19 05:56:56Z gervandiepen $
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27 |
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28 | //# Includes
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29 | #include <components/SpectralComponents/SpectralEstimate.h>
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30 |
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31 | #include <casa/BasicMath/Math.h>
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32 | #include <casa/BasicSL/Constants.h>
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33 | #include <casa/Utilities/Assert.h>
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34 | #include <components/SpectralComponents/CompiledSpectralElement.h>
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35 | #include <components/SpectralComponents/GaussianSpectralElement.h>
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36 | #include <components/SpectralComponents/PolynomialSpectralElement.h>
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37 |
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38 | namespace casa { //#Begin namespace casa
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39 |
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40 | //# Member templates
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41 | template <class MT>
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42 | const SpectralList &SpectralEstimate::estimate(const casacore::Vector<MT> &prof,
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43 | casacore::Vector<MT> *der) {
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44 | if (prof.nelements() != lprof_p) {
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45 | delete [] deriv_p; deriv_p = 0; lprof_p = 0;
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46 | lprof_p = prof.nelements();
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47 | deriv_p = new casacore::Double[lprof_p];
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48 | };
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49 | // Check if signal in window
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50 | if (!window(prof)) return slist_p;
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51 | // Limit window
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52 | windowEnd_p = min(windowEnd_p+q_p , casacore::Int(lprof_p));
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53 | windowLow_p = max(windowLow_p-q_p , 0 );
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54 | // Get the second derivatives
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55 | findc2(prof);
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56 | // Next for debugging
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57 | if (der) {
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58 | for (casacore::uInt i=0; i<lprof_p; i++) (*der)[i] = deriv_p[i];
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59 | };
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60 | // Find the estimates (sorted)
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61 | findga(prof);
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62 | // cout << slist_p << endl;
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63 | return slist_p;
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64 | }
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65 |
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66 | template <class MT>
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67 | const SpectralList& SpectralEstimate::estimate(const casacore::Vector<MT>& x,
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68 | const casacore::Vector<MT>& y)
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69 | {
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70 | if (x.nelements() != y.nelements()) {
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71 | throw(AipsError("Abcissa and ordinate vectors must be the same length"));
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72 | }
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73 | if (x.nelements()==1) {
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74 | throw(AipsError("Not enough elements in vectors"));
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75 | }
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76 | // Get pixel-based estimate (into slist_p)
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77 | estimate(y);
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78 | // Convert
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79 | for (casacore::uInt i=0; i<slist_p.nelements(); i++) {
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80 | if (slist_p[i]->getType() != SpectralElement::GAUSSIAN) {
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81 | throw AipsError("Non-gaussian spectral types cannot be estimated");
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82 | }
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83 | const GaussianSpectralElement elIn = *dynamic_cast<const GaussianSpectralElement *>(slist_p[i]);
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84 | GaussianSpectralElement elOut = convertElement (x, elIn);
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85 | slist_p.set(elOut, i);
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86 | }
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87 | return slist_p;
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88 | }
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89 |
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90 |
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91 | template <class MT>
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92 | casacore::uInt SpectralEstimate::window(const casacore::Vector<MT> &prof) {
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93 | windowLow_p =0;
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94 | windowEnd_p = 0;
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95 | if (!useWindow_p || rms_p <= 0.0 || lprof_p == 0) {
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96 | if (regionEnd_p) {
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97 | windowLow_p = min(max(0,regionLow_p),casacore::Int(lprof_p));
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98 | windowEnd_p = min(regionEnd_p, casacore::Int(lprof_p));
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99 | } else windowEnd_p = lprof_p;
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100 | return windowEnd_p-windowLow_p;
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101 | };
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102 | // Total flux in profile and max position
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103 | casacore::Double flux(0.0);
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104 | casacore::Double pmax(prof(0));
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105 | casacore::uInt imax(0);
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106 | for (casacore::Int i=windowLow_p; i<windowEnd_p; i++) {
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107 | if (prof(i)>pmax) {
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108 | pmax = prof(i);
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109 | imax = i;
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110 | };
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111 | flux += prof(i);
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112 | };
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113 | // No data
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114 | if (pmax < cutoff_p) return 0;
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115 | // Window boundaries; new/old base and centre; width
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116 | casacore::Int width(-1);
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117 | casacore::Int nw(0);
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118 | casacore::Double bnew(flux), bold;
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119 | casacore::Double cnew(imax), cold;
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120 | do {
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121 | width++;
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122 | cold = cnew;
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123 | bold = bnew;
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124 | windowLow_p = max(0, casacore::Int(cold-width+0.5));
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125 | windowEnd_p = min(casacore::Int(lprof_p), casacore::Int(cold+width+1.5));
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126 | // flux and first moment in window
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127 | casacore::Double s(0);
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128 | casacore::Double c(0);
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129 | for (casacore::Int i=windowLow_p; i<windowEnd_p; i++) {
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130 | s += prof(i);
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131 | c += i*prof(i);
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132 | };
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133 | bnew = flux-s;
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134 | nw = lprof_p-windowEnd_p+windowLow_p;
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135 | if (s != 0.0) {
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136 | cnew = c/s;
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137 | if (cnew < 0 || cnew >= lprof_p) cnew = cold;
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138 | };
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139 | } while (abs(bnew-bold) > rms_p && nw);
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140 | return windowEnd_p-windowLow_p;
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141 | }
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142 |
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143 | template <class MT>
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144 | void SpectralEstimate::findc2(const casacore::Vector<MT> &prof) {
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145 | for (casacore::Int i=windowLow_p; i<windowEnd_p; i++) {
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146 | // Moments
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147 | casacore::Double m0(0.0);
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148 | casacore::Double m2(0.0);
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149 | for (casacore::Int j = -q_p; j <= q_p; j++) {
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150 | casacore::Int k = i+j;
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151 | if (k >= 0 && k<casacore::Int(lprof_p)) {
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152 | // add to moments
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153 | m0 += prof(k);
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154 | m2 += prof(k)*j*j;
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155 | };
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156 | };
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157 | // get the derivative
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158 | deriv_p[i] = a_p*(m2-b_p*m0);
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159 | };
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160 | }
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161 |
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162 | template <class MT>
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163 | void SpectralEstimate::findga(const casacore::Vector<MT> &prof) {
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164 | casacore::Int i(windowLow_p-1);
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165 | // Window on Gaussian
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166 | casacore::Int iclo(windowLow_p);
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167 | casacore::Int ichi(windowLow_p);
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168 | // Peak counter
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169 | casacore::Int nmax = 0;
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170 | GaussianSpectralElement tspel;
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171 | while (++i < windowEnd_p) {
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172 | if (deriv_p[i] > 0.0) {
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173 | // At edge?
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174 | if (i > windowLow_p && i < windowEnd_p-1) {
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175 | // Peak in 2nd derivative
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176 | if (deriv_p[i-1] < deriv_p[i] && deriv_p[i+1] < deriv_p[i]) nmax++;
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177 | // At start
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178 | } else if (i == windowLow_p && deriv_p[i+1] < deriv_p[i]) nmax++;
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179 | // At end of window
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180 | else if (i == windowEnd_p-1 && deriv_p[i-1] < deriv_p[i]) nmax++;
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181 | };
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182 | switch (nmax) {
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183 | // Search for next peak
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184 | case 1:
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185 | break;
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186 | // Found a Gaussian
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187 | case 2: {
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188 | // Some moments
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189 | casacore::Double m0m(0);
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190 | casacore::Double m0(0);
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191 | casacore::Double m1(0);
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192 | casacore::Double m2(0);
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193 | ichi = i;
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194 | // Do Schwarz' calculation
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195 | casacore::Double b = deriv_p[iclo];
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196 | casacore::Double a = (deriv_p[ichi] - b) / (ichi-iclo);
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197 | for (casacore::Int ic=iclo; ic<=ichi; ic++) {
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198 | m0m += min(deriv_p[ic], 0.0);
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199 | casacore::Double wi = deriv_p[ic] - a*(ic-iclo) - b;
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200 | m0 += wi;
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201 | m1 += wi*ic;
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202 | m2 += wi*ic*ic;
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203 | };
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204 | // determinant
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205 | casacore::Double det = m2*m0 - m1*m1;
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206 | if (det > 0.0 && fabs(m0m) > FLT_EPSILON) {
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207 | casacore::Double xm = m1/m0;
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208 | casacore::Double sg = 1.69*sqrt(det) / fabs(m0);
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209 | // Width above critical?
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210 | if (sg > sigmin_p) {
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211 | casacore::Int is = casacore::Int(1.73*sg+0.5);
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212 | casacore::Int im = casacore::Int(xm+0.5);
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213 | casacore::Double yl(0);
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214 | if ((im-is) >= 0) yl = prof(im-is);
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215 | casacore::Double yh(0);
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216 | if ((im + is) <= casacore::Int(lprof_p-1)) yh = prof(im+is);
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217 | casacore::Double ym = prof(im);
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218 | // modified by dmehringer 2012apr03 to deal with 0 denominator
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219 | // 0.0/0.0 produces NaN on Linux but 0 on OSX
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220 | casacore::Double pg = (ym-0.5*(yh+yl));
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221 | if (pg != 0) {
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222 | casacore::Double denom = (1.0-exp(-0.5*(is*is)/sg/sg));
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223 | if (denom == 0) {
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224 | throw AipsError("Bailing because division by zero is undefined");
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225 | }
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226 | pg /= denom;
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227 | }
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228 | // end dmehring mods
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229 | pg = min(pg, ym);
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230 | // cout << "pg " << pg << " cutoff " << cutoff_p << endl;
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231 | // Above critical level? Add to list
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232 | if (pg > cutoff_p) {
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233 | // cout << pg << " " << xm << " " << sg << endl;
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234 | tspel.setAmpl(pg);
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235 | tspel.setCenter(xm);
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236 | tspel.setSigma(sg);
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237 | slist_p.insert(tspel);
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238 | };
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239 | };
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240 | };
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241 | // Next gaussian
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242 | iclo = ichi;
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243 | nmax--;
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244 | break;
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245 | }
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246 | default:
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247 | iclo = i+1;
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248 | break;
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249 | };
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250 | };
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251 | }
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252 |
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253 | template <class MT>
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254 | GaussianSpectralElement SpectralEstimate::convertElement (const casacore::Vector<MT>& x,
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255 | const GaussianSpectralElement& el) const
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256 | {
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257 | GaussianSpectralElement elOut = el;
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258 | const casacore::Int& idxMax = x.nelements()-1;
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259 |
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260 | // Get current (pars are amp, center, width as the SpectralElement
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261 | // will always be a Gaussian)
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262 |
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263 | casacore::Vector<casacore::Double> par, err;
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264 | el.get(par);
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265 | el.getError(err);
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266 |
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267 | // Center
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268 |
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269 | casacore::Int cenIdx = casacore::Int(par[1]);
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270 |
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271 | // Get the x-increment, local to the center, as best we can from
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272 | // the abcissa vector. The following algorithm assumes the X
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273 | // vector is monotonic
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274 |
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275 | casacore::Double incX;
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276 | if (cenIdx-1<0) {
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277 | incX = x[1] - x[0];
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278 | } else if (cenIdx+1>idxMax) {
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279 | incX = x[idxMax] - x[idxMax-1];
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280 | } else {
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281 | incX = 0.5 * (x(cenIdx+1) - x(cenIdx-1));
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282 | }
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283 | //
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284 | if (cenIdx<0) {
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285 | par[1] = incX*par[1] + x[0]; // Extrapolate from x[0]
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286 | } else if (cenIdx>idxMax) {
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287 | par[1] = incX*(par[1]-idxMax) + x[idxMax]; // Extrapolate from x[idxMax]
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288 | } else {
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289 | casacore::Double dIdx = par[1] - cenIdx;
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290 | par[1] = x[cenIdx] + dIdx*incX; // casacore::Interpolate
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291 | }
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292 | err[1] = abs(err[1] * incX);
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293 |
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294 | // Width
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295 |
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296 | par[2] = abs(par[2] * incX);
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297 | err[2] = abs(err[2] * incX);
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298 |
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299 | elOut.set(par);
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300 | elOut.setError(err);
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301 | return elOut;
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302 | }
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303 |
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304 |
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305 | } //# End namespace casa
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