| 1 | from asap._asap import sdtable
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| 2 | from numarray import ones
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| 3 | import sys
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| 4 |
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| 5 | class scantable(sdtable):
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| 6 | """
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| 7 | The ASAP container for scans
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| 8 | """
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| 9 | def functions(self):
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| 10 | return ['copy','get_scan','summary','rms','set_unit','create_mask']
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| 11 |
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| 12 | def __init__(self, filename):
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| 13 | """
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| 14 | Create a scantable from a saved one or make a reference
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| 15 | Parameters:
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| 16 | filename: the name of an asap table on disk, or
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| 17 | [advanced] a refernce to an existing
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| 18 | scantable
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| 19 | """
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| 20 | sdtable.__init__(self, filename)
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| 21 | self._unit = 'channel'
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| 22 |
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| 23 | def copy(self):
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| 24 | """
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| 25 | Return a copy of this scantable.
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| 26 | Parameters:
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| 27 |
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| 28 | Example:
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| 29 | copiedscan = scan.copy()
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| 30 | """
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| 31 | sd = sdtable._copy(self)
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| 32 | return scantable(sd)
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| 33 | def get_scan(self, scanid=None):
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| 34 | """
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| 35 | Return a specific scan (by scanno) or collection of scans (by
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| 36 | source name) in a new scantable.
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| 37 | Parameters:
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| 38 | scanid: a scanno or a source name
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| 39 | Example:
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| 40 | scan.getscan('323p459')
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| 41 | # gets all scans containing the source '323p459'
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| 42 | """
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| 43 | if scanid is None:
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| 44 | print "Please specify a scan no or name to retrieve from the scantable"
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| 45 | try:
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| 46 | if type(scanid) is str:
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| 47 | s = sdtable.getsource(self,scanid)
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| 48 | return scantable(s)
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| 49 | elif type(scanid) is int:
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| 50 | s = sdtable.getscan(self,scanid)
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| 51 | return scantable(s)
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| 52 | except RuntimeError:
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| 53 | print "Couldn't find any match."
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| 54 |
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| 55 | def __str__(self):
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| 56 | return sdtable.summary(self)
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| 57 |
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| 58 | def summary(self,filename=None):
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| 59 | """
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| 60 | Print a summary of the contents of this scantable.
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| 61 | Parameters:
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| 62 | filename: the name of a file to write the putput to
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| 63 | Default - no file output
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| 64 | """
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| 65 | info = sdtable.summary(self)
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| 66 | if filename is not None:
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| 67 | data = open(filename, 'w')
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| 68 | data.write(info)
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| 69 | data.close()
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| 70 | print info
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| 71 |
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| 72 | def set_selection(self, thebeam=0,theif=0,thepol=0):
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| 73 | """
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| 74 | Set the spectrum for individual operations.
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| 75 | Parameters:
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| 76 | thebeam,theif,thepol: a number
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| 77 | Example:
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| 78 | scan.set_selection(0,0,1)
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| 79 | pol1rms = scan.rms(all=False) # returns rms for beam=0
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| 80 | # if=0, pol=1
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| 81 | """
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| 82 | self.setbeam(thebeam)
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| 83 | self.setpol(thepol)
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| 84 | self.setif(theif)
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| 85 | return
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| 86 |
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| 87 | def get_selection(self):
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| 88 | i = self.getbeam()
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| 89 | j = self.getif()
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| 90 | k = self.getpol()
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| 91 | out = 'Beam=%d IF=%d Pol=%d '% (i,j,k)
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| 92 | print out
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| 93 | return i,j,k
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| 94 |
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| 95 | def rms(self,mask=None, all=True):
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| 96 | """
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| 97 | Determine the root mean square of the current beam/if/pol
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| 98 | Takes a 'mask' as an optional parameter to specify which
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| 99 | channels should be excluded.
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| 100 | Parameters:
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| 101 | mask: an optional mask specifying where the rms
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| 102 | should be determined.
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| 103 | all: optional flag to show all or a selected
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| 104 | spectrum of Beam/IF/Pol
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| 105 |
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| 106 | Example:
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| 107 | scan.setuint('channel')
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| 108 | msk = scan.create_mask([100,200],[500,600])
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| 109 | scan.rms(mask=m)
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| 110 | """
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| 111 | from asap._asap import rms as _rms
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| 112 | if mask == None:
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| 113 | mask = ones(self.nchan())
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| 114 | if all:
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| 115 | out = ''
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| 116 | tmp = []
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| 117 | for i in range(self.nbeam()):
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| 118 | self.setbeam(i)
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| 119 | for j in range(self.nif()):
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| 120 | self.setif(j)
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| 121 | for k in range(self.npol()):
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| 122 | self.setpol(k)
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| 123 | rmsval = _rms(self,mask)
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| 124 | tmp.append(rmsval)
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| 125 | out += 'Beam[%d], IF[%d], Pol[%d] = %3.3f\n' % (i,j,k,rmsval)
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| 126 | print out
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| 127 | return tmp
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| 128 |
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| 129 | else:
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| 130 | i = self.getbeam()
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| 131 | j = self.getif()
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| 132 | k = self.getpol()
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| 133 | rmsval = _rms(self,mask)
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| 134 | out = 'Beam[%d], IF[%d], Pol[%d] = %3.3f' % (i,j,k,rmsval)
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| 135 | print out
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| 136 | return rmsval
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| 137 |
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| 138 | def get_tsys(self, all=True):
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| 139 | if all:
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| 140 | tmp = []
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| 141 | out = ''
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| 142 | for i in range(self.nbeam()):
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| 143 | self.setbeam(i)
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| 144 | for j in range(self.nif()):
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| 145 | self.setif(j)
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| 146 | for k in range(self.npol()):
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| 147 | self.setpol(k)
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| 148 | ts = self.gettsys()
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| 149 | tmp.append(ts)
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| 150 | out += 'TSys: Beam[%d], IF[%d], Pol[%d] = %3.3f\n' % (i,j,k,ts)
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| 151 | print out
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| 152 | return tmp
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| 153 | else:
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| 154 | i = self.getbeam()
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| 155 | j = self.getif()
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| 156 | k = self.getpol()
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| 157 | ts = self.gettsys()
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| 158 | out = 'TSys: Beam[%d], IF[%d], Pol[%d] = %3.3f' % (i,j,k,ts)
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| 159 | print out
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| 160 | return ts
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| 161 |
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| 162 | def set_unit(self, unit='channel'):
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| 163 | """
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| 164 | Set the unit for all following operations on this scantable
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| 165 | Parameters:
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| 166 | unit: optional unit, default is 'channel'
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| 167 | one of 'GHz','MHz','km/s','channel'
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| 168 | """
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| 169 | units = ['GHz','MHz','km/s','channel','pixel','']
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| 170 | if unit in units:
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| 171 | if unit in ['','pixel']:
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| 172 | unit = 'channel'
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| 173 | self._unit = unit
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| 174 | else:
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| 175 | print "Invalid unit given, please use one of:"
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| 176 | print units
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| 177 |
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| 178 | def create_mask(self, *args):
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| 179 | """
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| 180 | Compute and return a mask based on [min,max] windows.
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| 181 | Parameters:
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| 182 | [min,max],[min2,max2],...
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| 183 | Pairs of start/end points specifying the regions
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| 184 | to be masked
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| 185 | Example:
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| 186 | scan.setunit('channel')
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| 187 | msk = scan.set_mask([400,500],[800,900])
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| 188 | masks the regions between 400 and 500
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| 189 | and 800 and 900 in the unit 'channel'
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| 190 | """
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| 191 | print "The current mask window unit is", self._unit
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| 192 | n = self.nchan()
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| 193 | if self._unit == 'channel':
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| 194 | data = range(n)
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| 195 | else:
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| 196 | data = self.getabscissa(unit=self._unit)
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| 197 | msk = ones(n)
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| 198 | for window in args:
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| 199 | if (len(window) != 2 or window[0] > window[1] ):
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| 200 | print "A window needs to be defined as [min,max]"
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| 201 | return
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| 202 | for i in range(n):
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| 203 | if data[i] > window[0] and data[i] < window[1]:
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| 204 | msk[i] = 0
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| 205 | return msk
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| 206 | def set_restfrequencies(self, freqs, unit='Hz'):
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| 207 | """
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| 208 | Set the restfrequency(s) for this scantable.
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| 209 | Parameters:
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| 210 | freqs: one or more frequencies
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| 211 | unit: optional 'unit', default 'Hz'
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| 212 | Example:
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| 213 | scan.set_restfrequencies([1000000000.0])
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| 214 | """
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| 215 | self.setrestfreqs(freqs, unit)
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| 216 | return
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| 217 |
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| 218 | def flag_spectrum(self, thebeam, theif, thepol):
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| 219 | """
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| 220 | This flags a selected spectrum in the scan 'for good'.
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| 221 | USE WITH CARE - not reversible.
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| 222 | Use masks for non-permanent exclusion of channels.
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| 223 | Parameters:
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| 224 | thebeam,theif,thepol: all have to be explicitly
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| 225 | specified
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| 226 | Example:
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| 227 | scan.flag_spectrum(0,0,1)
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| 228 | flags the spectrum for Beam=0, IF=0, Pol=1
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| 229 | """
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| 230 | if (thebeam < self.nbeam() and theif < self.nif() and thepol < self.npol()):
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| 231 | stable.setbeam(thebeam)
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| 232 | stable.setif(theif)
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| 233 | stable.setpol(thepol)
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| 234 | stable._flag(self)
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| 235 | else:
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| 236 | print "Please specify a valid (Beam/IF/Pol)"
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| 237 | return
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