| 1 | from scantable import scantable
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| 2 | from asap import rcParams
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| 3 |
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| 4 | def average_time(*args, **kwargs):
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| 5 | """
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| 6 | Return the (time) average of a scan or list of scans. [in channels only]
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| 7 | Parameters:
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| 8 | one scan or comma separated scans
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| 9 | mask: an optional mask (only used for 'var' and 'tsys' weighting)
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| 10 | scanav: False (default) averages all scans together,
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| 11 | True averages each scan separately
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| 12 | weight: Weighting scheme. 'none' (default), 'var' (variance
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| 13 | weighted), 'tsys'
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| 14 | Example:
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| 15 | # return a time averaged scan from scana and scanb
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| 16 | # without using a mask
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| 17 | scanav = average_time(scana,scanb)
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| 18 | # return the (time) averaged scan, i.e. the average of
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| 19 | # all correlator cycles
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| 20 | scanav = average_time(scan)
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| 21 |
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| 22 | """
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| 23 | scanAv = False
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| 24 | if kwargs.has_key('scanav'):
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| 25 | scanAv = kwargs.get('scanav')
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| 26 |
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| 27 | weight = 'none'
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| 28 | if kwargs.has_key('weight'):
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| 29 | weight = kwargs.get('weight')
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| 30 |
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| 31 | mask = ()
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| 32 | if kwargs.has_key('mask'):
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| 33 | mask = kwargs.get('mask')
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| 34 |
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| 35 | lst = tuple(args)
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| 36 | from asap._asap import average as _av
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| 37 | for s in lst:
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| 38 | if not isinstance(s,scantable):
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| 39 | print "Please give a list of scantables"
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| 40 | return
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| 41 | return scantable(_av(lst, mask, scanAv, weight))
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| 42 |
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| 43 | def quotient(source, reference, preserve=True):
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| 44 | """
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| 45 | Return the quotient of a 'source' (signal) scan and a 'reference' scan.
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| 46 | The reference can have just one row, even if the signal has many. Otherwise
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| 47 | they must have the same number of rows.
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| 48 | Parameters:
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| 49 | source: the 'on' scan
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| 50 | reference: the 'off' scan
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| 51 | preserve: you can preserve (default) the continuum or
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| 52 | remove it. The equations used are
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| 53 | preserve - Output = Tref * (sig/ref) - Tref
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| 54 | remove - Output = Tref * (sig/ref) - Tsig
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| 55 | """
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| 56 | from asap._asap import quotient as _quot
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| 57 | return scantable(_quot(source, reference, preserve))
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| 58 |
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| 59 | def simple_math(left, right, op='add'):
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| 60 | """
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| 61 | Apply simple mathematical binary operations to two
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| 62 | scan tables, returning the result in a new scan table.
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| 63 | The operation is applied to both the correlations and the TSys data
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| 64 | Parameters:
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| 65 | left: the 'left' scan
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| 66 | right: the 'right' scan
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| 67 | op: the operation: 'add' (default), 'sub', 'mul', 'div'
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| 68 | """
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| 69 | if not isinstance(left,scantable) and not isinstance(right,scantable):
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| 70 | print "Please provide two scantables as input"
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| 71 | return
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| 72 | from asap._asap import b_operate as _bop
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| 73 | return scantable(_bop(left, right, op))
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| 74 |
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| 75 | def scale(scan, factor, insitu=None, allaxes=None):
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| 76 | """
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| 77 | Return a scan where all spectra are scaled by the give 'factor'
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| 78 | Parameters:
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| 79 | scan: a scantable
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| 80 | factor: the scaling factor
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| 81 | insitu: if False a new scantable is returned.
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| 82 | Otherwise, the scaling is done in-situ
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| 83 | The default is taken from .asaprc (False)
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| 84 | allaxes: if True apply to all spectra. Otherwise
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| 85 | apply only to the selected (beam/pol/if)spectra only.
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| 86 | The default is taken from .asaprc (True)
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| 87 | """
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| 88 | if allaxes is None: allaxes = rcParams['scantable.allaxes']
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| 89 | if insitu is None: insitu = rcParams['insitu']
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| 90 | if not insitu:
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| 91 | from asap._asap import scale as _scale
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| 92 | return scantable(_scale(scan, factor, allaxes))
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| 93 | else:
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| 94 | from asap._asap import scale_insitu as _scale
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| 95 | _scale(scan, factor, allaxes)
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| 96 | return
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| 97 |
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| 98 |
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| 99 | def add(scan, offset, insitu=None, allaxes=None):
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| 100 | """
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| 101 | Return a scan where all spectra have the offset added
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| 102 | Parameters:
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| 103 | scan: a scantable
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| 104 | offset: the offset
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| 105 | insitu: if False a new scantable is returned.
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| 106 | Otherwise, the scaling is done in-situ
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| 107 | The default is taken from .asaprc (False)
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| 108 | allaxes: if True apply to all spectra. Otherwise
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| 109 | apply only to the selected (beam/pol/if)spectra only
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| 110 | The default is taken from .asaprc (True)
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| 111 | """
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| 112 | if allaxes is None: allaxes = rcParams['scantable.allaxes']
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| 113 | if insitu is None: insitu = rcParams['insitu']
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| 114 | if not insitu:
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| 115 | from asap._asap import add as _add
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| 116 | return scantable(_add(scan, offset, allaxes))
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| 117 | else:
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| 118 | from asap._asap import add_insitu as _add
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| 119 | _add(scan, offset, allaxes)
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| 120 | return
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| 121 |
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| 122 | def convert_flux(scan, area, eta=1.0, insitu=None, allaxes=None):
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| 123 | """
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| 124 | Return a scan where all spectra are converted to either Jansky or Kelvin
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| 125 | depending upon the flux units of the scan table.
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| 126 | Parameters:
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| 127 | scan: a scantable
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| 128 | area: the illuminated area of the telescope (m**2)
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| 129 | eta: The efficiency of the telescope (default 1.0)
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| 130 | insitu: if False a new scantable is returned.
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| 131 | Otherwise, the scaling is done in-situ
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| 132 | The default is taken from .asaprc (False)
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| 133 | allaxes: if True apply to all spectra. Otherwise
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| 134 | apply only to the selected (beam/pol/if)spectra only
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| 135 | The default is taken from .asaprc (True)
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| 136 | """
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| 137 | if allaxes is None: allaxes = rcParams['scantable.allaxes']
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| 138 | if insitu is None: insitu = rcParams['insitu']
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| 139 | if not insitu:
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| 140 | from asap._asap import convertflux as _convert
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| 141 | return scantable(_convert(scan, area, eta, allaxes))
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| 142 | else:
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| 143 | from asap._asap import convertflux_insitu as _convert
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| 144 | _convert(scan, area, eta, allaxes)
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| 145 | return
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| 146 |
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| 147 | def gain_el(scan, poly=None, filename="", method="linear", insitu=None, allaxes=None):
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| 148 | """
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| 149 | Return a scan after applying a gain-elevation correction. The correction
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| 150 | can be made via either a polynomial or a table-based interpolation
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| 151 | (and extrapolation if necessary).
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| 152 | You specify polynomial coefficients, an ascii table or neither.
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| 153 | If you specify neither, then a polynomial correction will be made
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| 154 | with built in coefficients known for certain telescopes (an error will
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| 155 | occur if the instrument is not known).
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| 156 | Parameters:
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| 157 | scan: a scantable
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| 158 | poly: Polynomial coefficients (default None) to compute a
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| 159 | gain-elevation correction as a function of
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| 160 | elevation (in degrees).
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| 161 | filename: The name of an ascii file holding correction factors.
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| 162 | The first row of the ascii file must give the column
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| 163 | names and these MUST include columns
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| 164 | "ELEVATION" (degrees) and "FACTOR" (multiply data by this)
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| 165 | somewhere.
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| 166 | The second row must give the data type of the column. Use
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| 167 | 'R' for Real and 'I' for Integer. An example file
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| 168 | would be:
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| 169 |
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| 170 | TIME ELEVATION FACTOR
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| 171 | R R R
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| 172 | 0.1 0 1.5
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| 173 | 0.2 20 1.4
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| 174 | 0.3 40 1.3
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| 175 | 0.4 60 1.2
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| 176 | 0.5 80 1.1
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| 177 | 0.6 90 1.0
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| 178 | method: Interpolation method when correcting from a table. Values
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| 179 | are "nearest", "linear" (default), "cubic" and "spline"
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| 180 | insitu: if False a new scantable is returned.
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| 181 | Otherwise, the scaling is done in-situ
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| 182 | The default is taken from .asaprc (False)
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| 183 | allaxes: if True apply to all spectra. Otherwise
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| 184 | apply only to the selected (beam/pol/if) spectra only
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| 185 | The default is taken from .asaprc (True)
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| 186 | """
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| 187 | if allaxes is None: allaxes = rcParams['scantable.allaxes']
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| 188 | if poly is None:
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| 189 | poly = ()
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| 190 | if insitu is None: insitu = rcParams['insitu']
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| 191 | if not insitu:
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| 192 | from asap._asap import gainel as _gainEl
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| 193 | return scantable(_gainEl(scan, poly, filename, method, allaxes))
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| 194 | else:
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| 195 | from asap._asap import gainel_insitu as _gainEl
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| 196 | _gainEl(scan, poly, filename, method, allaxes)
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| 197 | return
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| 198 |
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| 199 | def opacity(scan, tau, insitu=None, allaxes=None):
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| 200 | """
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| 201 | Return a scan after applying an opacity correction.
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| 202 | Parameters:
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| 203 | scan: a scantable
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| 204 | tau: Opacity from which the correction factor is exp(tau*ZD)
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| 205 | where ZD is the zenith-distance
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| 206 | insitu: if False a new scantable is returned.
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| 207 | Otherwise, the scaling is done in-situ
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| 208 | The default is taken from .asaprc (False)
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| 209 | allaxes: if True apply to all spectra. Otherwise
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| 210 | apply only to the selected (beam/pol/if)spectra only
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| 211 | The default is taken from .asaprc (True)
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| 212 | """
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| 213 | if allaxes is None: allaxes = rcParams['scantable.allaxes']
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| 214 | if insitu is None: insitu = rcParams['insitu']
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| 215 | if not insitu:
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| 216 | from asap._asap import opacity as _opacity
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| 217 | return scantable(_opacity(scan, tau, allaxes))
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| 218 | else:
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| 219 | from asap._asap import opacity_insitu as _opacity
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| 220 | _opacity(scan, tau, allaxes)
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| 221 | return
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| 222 |
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| 223 | def bin(scan, width=5, insitu=None):
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| 224 | """
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| 225 | Return a scan where all spectra have been binned up
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| 226 | width: The bin width (default=5) in pixels
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| 227 | insitu: if False a new scantable is returned.
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| 228 | Otherwise, the scaling is done in-situ
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| 229 | The default is taken from .asaprc (False)
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| 230 | """
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| 231 | if insitu is None: insitu = rcParams['insitu']
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| 232 | if not insitu:
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| 233 | from asap._asap import bin as _bin
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| 234 | return scantable(_bin(scan, width))
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| 235 | else:
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| 236 | from asap._asap import bin_insitu as _bin
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| 237 | _bin(scan, width)
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| 238 | return
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| 239 |
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| 240 | def average_pol(scan, mask=None, insitu=None):
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| 241 | """
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| 242 | Average the Polarisations together.
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| 243 | Parameters:
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| 244 | scan: The scantable
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| 245 | mask: An optional mask defining the region, where the
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| 246 | averaging will be applied. The output will have all
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| 247 | specified points masked.
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| 248 | insitu: if False a new scantable is returned.
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| 249 | Otherwise, the scaling is done in-situ
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| 250 | The default is taken from .asaprc (False)
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| 251 | Example:
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| 252 | polav = average_pols(myscan)
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| 253 | """
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| 254 | if mask is None:
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| 255 | mask = ()
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| 256 | if insitu is None: insitu = rcParams['insitu']
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| 257 | if not insitu:
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| 258 | from asap._asap import averagepol as _avpol
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| 259 | return scantable(_avpol(scan, mask))
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| 260 | else:
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| 261 | from asap._asap import averagepol_insitu as _avpol
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| 262 | _avpol(scan, mask)
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| 263 | return
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| 264 |
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| 265 | def smooth(scan, kernel="hanning", width=5.0, insitu=None, allaxes=None):
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| 266 | """
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| 267 | Smooth the spectrum by the specified kernel (conserving flux).
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| 268 | Parameters:
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| 269 | scan: The input scan
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| 270 | kernel: The type of smoothing kernel. Select from
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| 271 | 'hanning' (default), 'gaussian' and 'boxcar'.
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| 272 | The first three characters are sufficient.
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| 273 | width: The width of the kernel in pixels. For hanning this is
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| 274 | ignored otherwise it defauls to 5 pixels.
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| 275 | For 'gaussian' it is the Full Width Half
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| 276 | Maximum. For 'boxcar' it is the full width.
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| 277 | insitu: if False a new scantable is returned.
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| 278 | Otherwise, the scaling is done in-situ
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| 279 | The default is taken from .asaprc (False)
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| 280 | allaxes: If True (default) apply to all spectra. Otherwise
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| 281 | apply only to the selected (beam/pol/if)spectra only
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| 282 | The default is taken from .asaprc (True)
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| 283 | Example:
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| 284 | none
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| 285 | """
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| 286 | if allaxes is None: allaxes = rcParams['scantable.allaxes']
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| 287 | if insitu is None: insitu = rcParams['insitu']
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| 288 | if not insitu:
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| 289 | from asap._asap import smooth as _smooth
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| 290 | return scantable(_smooth(scan,kernel,width,allaxes))
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| 291 | else:
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| 292 | from asap._asap import smooth_insitu as _smooth
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| 293 | _smooth(scan,kernel,width,allaxes)
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| 294 | return
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| 295 |
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| 296 | def poly_baseline(scan, mask=None, order=0, insitu=None):
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| 297 | """
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| 298 | Return a scan which has been baselined (all rows) by a polynomial.
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| 299 | Parameters:
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| 300 | scan: a scantable
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| 301 | mask: an optional mask
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| 302 | order: the order of the polynomial (default is 0)
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| 303 | insitu: if False a new scantable is returned.
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| 304 | Otherwise, the scaling is done in-situ
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| 305 | The default is taken from .asaprc (False)
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| 306 | Example:
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| 307 | # return a scan baselined by a third order polynomial,
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| 308 | # not using a mask
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| 309 | bscan = poly_baseline(scan, order=3)
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| 310 | """
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| 311 | from asap.asapfitter import fitter
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| 312 | if mask is None:
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| 313 | from numarray import ones
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| 314 | mask = tuple(ones(scan.nchan()))
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| 315 | f = fitter()
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| 316 | f._verbose(True)
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| 317 | f.set_scan(scan, mask)
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| 318 | f.set_function(poly=order)
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| 319 | sf = f.auto_fit(insitu)
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| 320 | return sf
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