[101] | 1 | from scantable import scantable |
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| 2 | |
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[143] | 3 | def average_time(*args, **kwargs): |
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[101] | 4 | """ |
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[113] | 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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[143] | 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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[113] | 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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[129] | 16 | scanav = average_time(scana,scanb) |
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[113] | 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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[143] | 20 | |
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[101] | 21 | """ |
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[143] | 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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[113] | 36 | for s in lst: |
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[101] | 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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[143] | 40 | return scantable(_av(lst, mask, scanAv, weight)) |
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[101] | 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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[242] | 52 | def b_operate(left, right, op='add'): |
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| 53 | """ |
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| 54 | Apply simple mathematical binary operations to two |
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| 55 | scan tables, returning the result in a new scan table. |
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| 56 | The operation is applied to both the correlations and the TSys data |
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| 57 | Parameters: |
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| 58 | left: the 'left' scan |
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| 59 | right: the 'right' scan |
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| 60 | op: the operation: 'add' (default), 'sub', 'mul', 'div' |
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| 61 | """ |
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| 62 | from asap._asap import b_operate as _bop |
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| 63 | return scantable(_bop(left, right, op)) |
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| 64 | |
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[150] | 65 | def scale(scan, factor, insitu=False, all=True): |
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[101] | 66 | """ |
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| 67 | Return a scan where all spectra are scaled by the give 'factor' |
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| 68 | Parameters: |
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| 69 | scan: a scantable |
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[113] | 70 | factor: the scaling factor |
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[150] | 71 | insitu: if False (default) a new scantable is returned. |
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| 72 | Otherwise, the scaling is done in-situ |
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| 73 | all: if True (default) apply to all spectra. Otherwise |
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| 74 | apply only to the selected (beam/pol/if)spectra only |
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[101] | 75 | """ |
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[141] | 76 | if not insitu: |
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| 77 | from asap._asap import scale as _scale |
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[150] | 78 | return scantable(_scale(scan, factor, all)) |
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[141] | 79 | else: |
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| 80 | from asap._asap import scale_insitu as _scale |
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[150] | 81 | _scale(scan, factor, all) |
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[141] | 82 | return |
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| 83 | |
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[101] | 84 | |
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[150] | 85 | def add(scan, offset, insitu=False, all=True): |
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[113] | 86 | """ |
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[150] | 87 | Return a scan where all spectra have the offset added |
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[113] | 88 | Parameters: |
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| 89 | scan: a scantable |
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[150] | 90 | offset: the offset |
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| 91 | insitu: if False (default) a new scantable is returned. |
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| 92 | Otherwise, the addition is done in-situ |
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| 93 | all: if True (default) apply to all spectra. Otherwise |
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| 94 | apply only to the selected (beam/pol/if)spectra only |
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[113] | 95 | """ |
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[150] | 96 | if not insitu: |
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| 97 | from asap._asap import add as _add |
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| 98 | return scantable(_add(scan, offset, all)) |
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| 99 | else: |
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| 100 | from asap._asap import add_insitu as _add |
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| 101 | _add(scan, offset, all) |
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| 102 | return |
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| 103 | |
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[225] | 104 | def convert_flux(scan, area, eta=1.0, insitu=False, all=True): |
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[224] | 105 | """ |
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| 106 | Return a scan where all spectra are converted to either Jansky or Kelvin |
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| 107 | depending upon the flux units of the scan table. |
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| 108 | Parameters: |
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| 109 | scan: a scantable |
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| 110 | area: the illuminated area of the telescope (m**2) |
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| 111 | eta: The efficiency of the telescope (default 1.0) |
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| 112 | insitu: if False (default) a new scantable is returned. |
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| 113 | Otherwise, the conversion is done in-situ |
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| 114 | all: if True (default) apply to all spectra. Otherwise |
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| 115 | apply only to the selected (beam/pol/if)spectra only |
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| 116 | """ |
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| 117 | if not insitu: |
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| 118 | from asap._asap import convertflux as _convert |
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| 119 | return scantable(_convert(scan, area, eta, all)) |
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| 120 | else: |
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| 121 | from asap._asap import convertflux_insitu as _convert |
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| 122 | _convert(scan, area, eta, all) |
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| 123 | return |
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[229] | 124 | |
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[242] | 125 | def gain_el(scan, poly=None, filename="", method="linear", insitu=False, all=True): |
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[229] | 126 | """ |
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[242] | 127 | Return a scan after applying a gain-elevation correction. The correction |
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| 128 | can be made via either a polynomial or a table-based interpolation |
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| 129 | (and extrapolation if necessary). |
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| 130 | You specify polynomial coefficients, an ascii table or neither. |
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| 131 | If you specify neither, then a polynomial correction will be made |
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| 132 | with built in coefficients known for certain telescopes (an error will |
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| 133 | occur if the instrument is not known). |
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[229] | 134 | Parameters: |
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| 135 | scan: a scantable |
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[242] | 136 | poly: Polynomial coefficients (default None) to compute a gain-elevation |
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| 137 | correction as a function of elevation (in degrees). |
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| 138 | filename: The name of an ascii file holding correction factors. |
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| 139 | The first row of the ascii file must give the column |
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| 140 | names and these MUST include columns |
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| 141 | "ELEVATION" (degrees) and "FACTOR" (multiply data by this) somewhere. |
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[229] | 142 | The second row must give the data type of the column. Use 'R' for |
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| 143 | Real and 'I' for Integer. An example file would be: |
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| 144 | |
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[242] | 145 | TIME ELEVATION FACTOR |
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| 146 | R R R |
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| 147 | 0.1 0 1.5 |
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| 148 | 0.2 20 1.4 |
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| 149 | 0.3 40 1.3 |
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| 150 | 0.4 60 1.2 |
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| 151 | 0.5 80 1.1 |
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| 152 | 0.6 90 1.0 |
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| 153 | method: Interpolation method when correcting from a table. Values |
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| 154 | are "nearest", "linear" (default), "cubic" and "spline" |
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[229] | 155 | insitu: if False (default) a new scantable is returned. |
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| 156 | Otherwise, the conversion is done in-situ |
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| 157 | all: if True (default) apply to all spectra. Otherwise |
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| 158 | apply only to the selected (beam/pol/if)spectra only |
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| 159 | """ |
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[242] | 160 | if poly is None: |
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| 161 | poly = () |
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[229] | 162 | if not insitu: |
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| 163 | from asap._asap import gainel as _gainEl |
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[242] | 164 | return scantable(_gainEl(scan, poly, filename, method, all)) |
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[229] | 165 | else: |
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| 166 | from asap._asap import gainel_insitu as _gainEl |
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[242] | 167 | _gainEl(scan, poly, filename, method, all) |
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[229] | 168 | return |
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[224] | 169 | |
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[242] | 170 | def opacity(scan, tau, insitu=False, all=True): |
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| 171 | """ |
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| 172 | Return a scan after applying an opacity correction. |
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| 173 | Parameters: |
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| 174 | scan: a scantable |
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| 175 | tau: Opacity from which the correction factor is exp(tau*ZD) |
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| 176 | where ZD is the zenith-distance |
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| 177 | insitu: if False (default) a new scantable is returned. |
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| 178 | Otherwise, the conversion is done in-situ |
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| 179 | all: if True (default) apply to all spectra. Otherwise |
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| 180 | apply only to the selected (beam/pol/if)spectra only |
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| 181 | """ |
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| 182 | if not insitu: |
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| 183 | from asap._asap import opacity as _opacity |
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| 184 | return scantable(_opacity(scan, tau, all)) |
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| 185 | else: |
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| 186 | from asap._asap import opacity_insitu as _opacity |
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| 187 | _opacity(scan, tau, all) |
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| 188 | return |
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| 189 | |
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[167] | 190 | def bin(scan, width=5, insitu=False): |
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[101] | 191 | """ |
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[167] | 192 | Return a scan where all spectra have been binned up |
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[172] | 193 | width: The bin width (default=5) in pixels |
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[167] | 194 | insitu: if False (default) a new scantable is returned. |
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| 195 | Otherwise, the addition is done in-situ |
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[101] | 196 | """ |
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[167] | 197 | if not insitu: |
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| 198 | from asap._asap import bin as _bin |
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| 199 | return scantable(_bin(scan, width)) |
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| 200 | else: |
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| 201 | from asap._asap import bin_insitu as _bin |
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| 202 | _bin(scan, width) |
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| 203 | return |
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[113] | 204 | |
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[166] | 205 | def average_pol(scan, mask=None, insitu=False): |
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[113] | 206 | """ |
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| 207 | Average the Polarisations together. |
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| 208 | Parameters: |
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[172] | 209 | scan: The scantable |
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| 210 | mask: An optional mask defining the region, where the |
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| 211 | averaging will be applied. The output will have all |
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| 212 | specified points masked. |
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| 213 | insitu: If False (default) a new scantable is returned. |
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[166] | 214 | Otherwise, the averaging is done in-situ |
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[113] | 215 | Example: |
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| 216 | polav = average_pols(myscan) |
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| 217 | """ |
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| 218 | if mask is None: |
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[166] | 219 | mask = () |
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| 220 | if not insitu: |
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| 221 | from asap._asap import averagepol as _avpol |
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| 222 | return scantable(_avpol(scan, mask)) |
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| 223 | else: |
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| 224 | from asap._asap import averagepol_insitu as _avpol |
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| 225 | _avpol(scan, mask) |
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| 226 | return |
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[113] | 227 | |
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[180] | 228 | def smooth(scan, kernel="hanning", width=5.0, insitu=False, all=True): |
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[113] | 229 | """ |
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[180] | 230 | Smooth the spectrum by the specified kernel (conserving flux). |
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[113] | 231 | Parameters: |
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[172] | 232 | scan: The input scan |
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[180] | 233 | kernel: The type of smoothing kernel. Select from |
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| 234 | 'hanning' (default), 'gaussian' and 'boxcar'. |
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| 235 | The first three characters are sufficient. |
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| 236 | width: The width of the kernel in pixels. For hanning this is |
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| 237 | ignored otherwise it defauls to 5 pixels. |
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| 238 | For 'gaussian' it is the Full Width Half |
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| 239 | Maximum. For 'boxcar' it is the full width. |
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[172] | 240 | insitu: If False (default) a new scantable is returned. |
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| 241 | Otherwise, the scaling is done in-situ |
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[180] | 242 | all: If True (default) apply to all spectra. Otherwise |
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| 243 | apply only to the selected (beam/pol/if)spectra only |
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[113] | 244 | Example: |
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| 245 | none |
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| 246 | """ |
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[172] | 247 | if not insitu: |
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[180] | 248 | from asap._asap import smooth as _smooth |
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| 249 | return scantable(_smooth(scan,kernel,width,all)) |
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[172] | 250 | else: |
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[180] | 251 | from asap._asap import smooth_insitu as _smooth |
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| 252 | _smooth(scan,kernel,width,all) |
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[172] | 253 | return |
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[113] | 254 | |
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| 255 | def poly_baseline(scan, mask=None, order=0): |
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| 256 | """ |
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[160] | 257 | Return a scan which has been baselined (all rows) by a polynomial. |
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[113] | 258 | Parameters: |
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| 259 | scan: a scantable |
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| 260 | mask: an optional mask |
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| 261 | order: the order of the polynomial (default is 0) |
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| 262 | Example: |
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| 263 | # return a scan baselined by a third order polynomial, |
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| 264 | # not using a mask |
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| 265 | bscan = poly_baseline(scan, order=3) |
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| 266 | """ |
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| 267 | from asap.asapfitter import fitter |
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| 268 | if mask is None: |
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| 269 | from numarray import ones |
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| 270 | mask = tuple(ones(scan.nchan())) |
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| 271 | f = fitter() |
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| 272 | f._verbose(True) |
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| 273 | f.set_scan(scan, mask) |
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| 274 | f.set_function(poly=order) |
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| 275 | sf = f.auto_fit() |
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| 276 | return sf |
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