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