Source Code for Module reflectometry.reduction.normcor

 1  # This program is public domain 
 2   
 3  """ 
 4  Monitor normalization correction. 
 5  """ 
 6   
 7  from numpy import sqrt 
 8  from reflectometry.reduction.correction import Correction 
 9  from reflectometry.reduction import err1d 
10   
11 -class Normalize(Correction): 
12 -    def __init__(self, base='auto'): 
13          """ 
14          Define the kind of monitor normalization. 
15          base is 'time', 'counts', 'power', 'auto' or 'none'. 
16          """ 
17          self.base = base 
18   
19 -    def apply(self, data): 
20          base = data.monitor.base if self.base == 'auto' else self.base 
21          C = data.detector.counts 
22          varC = C # Poisson stats 
23          if base == 'counts': 
24              M = data.monitor.counts 
25              varM = M # Poisson stats 
26              units = 'counts per monitor count' 
27          elif base == 'time': 
28              M = data.monitor.count_time 
29              # Uniform distribution has variance of interval/12 
30              varM = data.monitor.time_step/12. 
31              units = 'counts per second' 
32          elif base == 'power': 
33              M = data.monitor.source_power 
34              varM = 0 
35              units = 'counts per '+data.monitor.source_power_units 
36          elif base == 'none': 
37              M = 1 
38              varM = 0 
39              units = 'counts' 
40          else: 
41              raise ValueError,\ 
42                  "Expected normalization of auto, counts, time, power or none" 
43          data.R,data.varR = err1d.div(C,varC,M,varM) 
44          data.vunits = units 
45          data.vlabel = 'Intensity' 
46   
47 -    def __str__(self): 
48          return "Normalize('%s')"%self.base 
49