Added scale1bit.py from Jay

scale1bit.py

@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+### --- scale1bit.py --- ####
+### JMB Oct 2018 ###
+### TACL by HV Oct 2018 ###
+### Scales 1 bit data to account for quantization loss factors    
+
+import pyrap.tables
+import math
+import argparse
+import sys #for exit
+import os.path
+
+#old glish comments for safekeeping
+# value of factor updated 20nov2015:  \sqrt{(pi/2)/1.1329552}
+###  1.1329552 = 2bit-2bit correction factor already present in SFXC output
+###  pi/2 = what would be the case for 1bit-1bit data
+###  \sqrt = to get to 2bit-1bit factor, which forms the basis for the
+###     existing logic
+##  factor := 1.17631;
+##  factor := 1.177480083;
+
+
+factor1b1b = math.pi /2.0 / 1.1329552
+factor1b2b = math.sqrt(factor1b1b)
+
+# debug function for feedback
+def debug(*msg, **kwargs):
+    if args.verbose:
+        print (*msg, file=sys.stderr, **kwargs)
+
+
+#handle command line arguments: ms, antenna
+
+parser = argparse.ArgumentParser(description='Scale 1 bit data to correct quantization losses')
+parser.add_argument('ms', help="The measurement set to be corrected")
+parser.add_argument('ant',nargs='+', help="The antenna(s) to correct (space delimited)")
+parser.add_argument('-v', '--verbose', help="Print debug information", action="store_true")
+parser.add_argument('-u', '--undo', help="Undo a previous run, take care to specify the same stations!", action="store_true")
+parser.add_argument('-w', '--scale-weights', help="Also scale the weights", dest='to_scale', default=['DATA'], action='append_const', const='WEIGHT')
+args = parser.parse_args()
+
+if not os.path.exists(args.ms):
+    print("Error, no such ms found!")
+    sys.exit(1)
+
+try:
+    # query antenna table to translate 1 or more antenna names into antenna id's
+    aList   = list(pyrap.tables.taql("""SELECT ROWID() AS ANTENNAS FROM {table}::ANTENNA
+                                      WHERE UPCASE(NAME) IN {0}""".format(
+                                          list(map(str.upper, args.ant)),table=args.ms)
+                                    ).getcol('ANTENNAS'))
+
+except Exception as e:
+    print(e, "AAAAAAAAAARGH we have no such dishes, abort fail die :'(")
+    sys.exit(1)
+
+debug("Antenna list:", aList)
+# depending on length of the result, use "ANTENNAx == <id>" or "ANTENNAx IN [<id>, <id>,...]" 
+# because "==" is faster than "IN [<id>]" when only one <id> is present
+antcond = ("== {0[0]}".format if len(aList)==1 else "IN {0}".format)(aList)
+# and let taql do the real work ...
+factor1, factor2 = (factor1b1b, factor1b2b) if not args.undo else (1/factor1b1b, 1/factor1b2b)
+
+scale_it = "{{0}} = {{0}} * IIF(apply.ant1bit AND apply.ant2bit, {factor1b1b}, {factor1b2b})".format(factor1b1b=factor1, factor1b2b=factor2).format
+
+#to_scale = ['DATA'] + (['WEIGHT'] if args.scale_weights else [])
+
+t = pyrap.tables.taql("""
+    UPDATE {table}
+    SET  {todo}
+    FROM [SELECT ANTENNA1 {condition} AS ant1bit, ANTENNA2 {condition} AS ant2bit
+          FROM {table} GIVING AS memory] apply
+    WHERE ((apply.ant1bit OR apply.ant2bit) and ANTENNA1 != ANTENNA2)
+""".format(condition=antcond, table=args.ms, todo=",".join(map(scale_it, args.to_scale))))