1 | from scantable import scantable
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2 |
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3 | def average_time(*args, **kwargs):
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4 | """
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5 | Return the (time) average of a scan or list of scans. [in channels only]
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6 | Parameters:
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7 | one scan or comma separated scans
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8 | mask: an optional mask (only used for 'var' and 'tsys' weighting)
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9 | scanav: False (default) averages all scans together,
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10 | True averages each scan separately
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11 | weight: Weighting scheme. 'none' (default), 'var' (variance
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12 | weighted), 'tsys'
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13 | Example:
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14 | # return a time averaged scan from scana and scanb
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15 | # without using a mask
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16 | scanav = average_time(scana,scanb)
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17 | # return the (time) averaged scan, i.e. the average of
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18 | # all correlator cycles
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19 | scanav = average_time(scan)
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20 |
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21 | """
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22 | scanAv = False
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23 | if kwargs.has_key('scanav'):
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24 | scanAv = kwargs.get('scanav')
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25 | #
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26 | weight = 'none'
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27 | if kwargs.has_key('weight'):
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28 | weight = kwargs.get('weight')
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29 | #
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30 | mask = ()
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31 | if kwargs.has_key('mask'):
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32 | mask = kwargs.get('mask')
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33 | #
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34 | lst = tuple(args)
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35 | from asap._asap import average as _av
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36 | for s in lst:
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37 | if not isinstance(s,scantable):
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38 | print "Please give a list of scantables"
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39 | return
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40 | return scantable(_av(lst, mask, scanAv, weight))
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41 |
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42 | def quotient(source, reference):
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43 | """
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44 | Return the quotient of a 'source' scan and a 'reference' scan
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45 | Parameters:
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46 | source: the 'on' scan
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47 | reference: the 'off' scan
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48 | """
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49 | from asap._asap import quotient as _quot
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50 | return scantable(_quot(source, reference))
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51 |
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52 | def scale(scan, factor, insitu=False, all=True):
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53 | """
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54 | Return a scan where all spectra are scaled by the give 'factor'
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55 | Parameters:
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56 | scan: a scantable
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57 | factor: the scaling factor
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58 | insitu: if False (default) a new scantable is returned.
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59 | Otherwise, the scaling is done in-situ
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60 | all: if True (default) apply to all spectra. Otherwise
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61 | apply only to the selected (beam/pol/if)spectra only
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62 | """
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63 | if not insitu:
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64 | from asap._asap import scale as _scale
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65 | return scantable(_scale(scan, factor, all))
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66 | else:
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67 | from asap._asap import scale_insitu as _scale
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68 | _scale(scan, factor, all)
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69 | return
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70 |
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71 |
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72 | def add(scan, offset, insitu=False, all=True):
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73 | """
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74 | Return a scan where all spectra have the offset added
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75 | Parameters:
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76 | scan: a scantable
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77 | offset: the offset
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78 | insitu: if False (default) a new scantable is returned.
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79 | Otherwise, the addition is done in-situ
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80 | all: if True (default) apply to all spectra. Otherwise
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81 | apply only to the selected (beam/pol/if)spectra only
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82 | """
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83 | if not insitu:
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84 | from asap._asap import add as _add
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85 | return scantable(_add(scan, offset, all))
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86 | else:
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87 | from asap._asap import add_insitu as _add
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88 | _add(scan, offset, all)
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89 | return
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90 |
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91 | def convert_flux(scan, area, eta=1.0, insitu=False, all=True):
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92 | """
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93 | Return a scan where all spectra are converted to either Jansky or Kelvin
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94 | depending upon the flux units of the scan table.
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95 | Parameters:
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96 | scan: a scantable
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97 | area: the illuminated area of the telescope (m**2)
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98 | eta: The efficiency of the telescope (default 1.0)
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99 | insitu: if False (default) a new scantable is returned.
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100 | Otherwise, the conversion is done in-situ
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101 | all: if True (default) apply to all spectra. Otherwise
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102 | apply only to the selected (beam/pol/if)spectra only
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103 | """
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104 | if not insitu:
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105 | from asap._asap import convertflux as _convert
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106 | return scantable(_convert(scan, area, eta, all))
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107 | else:
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108 | from asap._asap import convertflux_insitu as _convert
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109 | _convert(scan, area, eta, all)
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110 | return
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111 |
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112 | def gain_el(scan, filename="gainel.txt", method="linear", insitu=False, all=True):
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113 | """
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114 | Return a scan after applying a gain-elevation correction via interpolation
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115 | (and extrapolation if necessary) from values in an ascii file.
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116 | Parameters:
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117 | scan: a scantable
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118 | filename: The name of the ASCII file holding the data. The first row
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119 | must give the column names. These MUST include columns
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120 | "ELEVATION" (degrees) and "FACTOR" (multiply data by this) somewhere.
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121 | The second row must give the data type of the column. Use 'R' for
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122 | Real and 'I' for Integer. An example file would be:
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123 |
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124 | ELEVATION FACTOR
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125 | R R
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126 | 0 1.5
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127 | 20 1.4
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128 | 40 1.3
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129 | 60 1.2
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130 | 80 1.1
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131 | 90 1.0
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132 | method: Interpolation method. "nearest", "linear" (default),
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133 | "cubic" and "spline"
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134 | insitu: if False (default) a new scantable is returned.
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135 | Otherwise, the conversion is done in-situ
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136 | all: if True (default) apply to all spectra. Otherwise
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137 | apply only to the selected (beam/pol/if)spectra only
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138 | """
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139 | if not insitu:
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140 | from asap._asap import gainel as _gainEl
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141 | return scantable(_gainEl(scan, filename, method, all))
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142 | else:
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143 | from asap._asap import gainel_insitu as _gainEl
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144 | _gainEl(scan, filename, method, all)
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145 | return
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146 |
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147 | def bin(scan, width=5, insitu=False):
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148 | """
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149 | Return a scan where all spectra have been binned up
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150 | width: The bin width (default=5) in pixels
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151 | insitu: if False (default) a new scantable is returned.
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152 | Otherwise, the addition is done in-situ
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153 | """
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154 | if not insitu:
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155 | from asap._asap import bin as _bin
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156 | return scantable(_bin(scan, width))
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157 | else:
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158 | from asap._asap import bin_insitu as _bin
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159 | _bin(scan, width)
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160 | return
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161 |
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162 | def average_pol(scan, mask=None, insitu=False):
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163 | """
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164 | Average the Polarisations together.
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165 | Parameters:
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166 | scan: The scantable
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167 | mask: An optional mask defining the region, where the
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168 | averaging will be applied. The output will have all
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169 | specified points masked.
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170 | insitu: If False (default) a new scantable is returned.
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171 | Otherwise, the averaging is done in-situ
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172 | Example:
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173 | polav = average_pols(myscan)
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174 | """
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175 | if mask is None:
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176 | mask = ()
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177 | if not insitu:
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178 | from asap._asap import averagepol as _avpol
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179 | return scantable(_avpol(scan, mask))
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180 | else:
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181 | from asap._asap import averagepol_insitu as _avpol
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182 | _avpol(scan, mask)
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183 | return
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184 |
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185 | def smooth(scan, kernel="hanning", width=5.0, insitu=False, all=True):
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186 | """
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187 | Smooth the spectrum by the specified kernel (conserving flux).
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188 | Parameters:
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189 | scan: The input scan
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190 | kernel: The type of smoothing kernel. Select from
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191 | 'hanning' (default), 'gaussian' and 'boxcar'.
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192 | The first three characters are sufficient.
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193 | width: The width of the kernel in pixels. For hanning this is
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194 | ignored otherwise it defauls to 5 pixels.
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195 | For 'gaussian' it is the Full Width Half
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196 | Maximum. For 'boxcar' it is the full width.
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197 | insitu: If False (default) a new scantable is returned.
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198 | Otherwise, the scaling is done in-situ
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199 | all: If True (default) apply to all spectra. Otherwise
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200 | apply only to the selected (beam/pol/if)spectra only
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201 | Example:
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202 | none
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203 | """
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204 | if not insitu:
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205 | from asap._asap import smooth as _smooth
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206 | return scantable(_smooth(scan,kernel,width,all))
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207 | else:
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208 | from asap._asap import smooth_insitu as _smooth
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209 | _smooth(scan,kernel,width,all)
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210 | return
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211 |
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212 | def poly_baseline(scan, mask=None, order=0):
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213 | """
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214 | Return a scan which has been baselined (all rows) by a polynomial.
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215 | Parameters:
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216 | scan: a scantable
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217 | mask: an optional mask
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218 | order: the order of the polynomial (default is 0)
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219 | Example:
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220 | # return a scan baselined by a third order polynomial,
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221 | # not using a mask
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222 | bscan = poly_baseline(scan, order=3)
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223 | """
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224 | from asap.asapfitter import fitter
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225 | if mask is None:
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226 | from numarray import ones
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227 | mask = tuple(ones(scan.nchan()))
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228 | f = fitter()
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229 | f._verbose(True)
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230 | f.set_scan(scan, mask)
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231 | f.set_function(poly=order)
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232 | sf = f.auto_fit()
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233 | return sf
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