Source Code for Module reflectometry.reduction.formatnum

  1  # This program is public domain 
  2  """ 
  3  Format numbers nicely for printing. 
  4  """ 
  5   
  6  import math 
  7  __all__ = ['format_uncertainty'] 
  8   
  9 -def format_uncertainty(value,uncertainty): 
 10      """ 
 11      Given a value and an uncertainty, return a concise string representation. 
 12   
 13      The returned string uses only the number of digits warranted by the 
 14      uncertainty in the measurement. 
 15      """ 
 16      if uncertainty == None: 
 17          return "%g"%value 
 18   
 19      # Process sign 
 20      sign = "-" if value < 0 else "" 
 21      value = abs(value) 
 22   
 23      # Represent error as (##) at the end of the digit string 
 24      val_place = int(math.floor(math.log10(value))) 
 25      err_place = int(math.floor(math.log10(uncertainty))) 
 26      err_str = "(%2d)"%int(uncertainty/10.**(err_place-1)+0.5) 
 27   
 28      if err_place > val_place: 
 29          # Degenerate case: error bigger than value 
 30          # The mantissa is 0.#(##)e#, 0.0#(##)e# or 0.00#(##)e# 
 31          if err_place - val_place > 2: value = 0 
 32          val_place = int(math.floor((err_place+2)/3.))*3 
 33          digits_after_decimal = val_place - err_place + 1 
 34          val_str = "%.*f%s"%(digits_after_decimal,value/10.**val_place,err_str) 
 35          if val_place != 0: val_str += "e%d"%val_place 
 36      elif err_place == val_place: 
 37          # Degenerate case: error and value the same order of magnitude 
 38          # The value is ##(##)e#, #.#(##)e# or 0.##(##)e# 
 39          val_place = int(math.floor((err_place+1)/3.))*3 
 40          digits_after_decimal = val_place - err_place + 1 
 41          val_str = "%.*f%s"%(digits_after_decimal,value/10.**val_place,err_str) 
 42          if val_place != 0: val_str += "e%d"%val_place 
 43      elif err_place <= 1 and val_place >= -3: 
 44          # Normal case: nice numbers and errors 
 45          # The value is ###.###(##) 
 46          digits_after_decimal = abs(err_place-1) 
 47          val_str = "%.*f%s"%(digits_after_decimal,value,err_str) 
 48      else: 
 49          # Extreme cases: zeros before value or after error 
 50          # The value is ###.###(##)e#, ##.####(##)e# or #.#####(##)e# 
 51          total_digits = val_place - err_place + 2 
 52          val_place = int(math.floor(val_place/3.))*3 
 53          val_str = "%.*g%se%d"%(total_digits, 
 54                                 value/10.**val_place, 
 55                                 err_str,val_place) 
 56   
 57      return sign+val_str 
 58   
 59   
 60 -def test(): 
 61      value_str = format_uncertainty  # Changed name after testing 
 62   
 63      # val_place > err_place 
 64      assert value_str(1235670,766000) == "1.24(77)e6" 
 65      assert value_str(123567.,76600) == "124(77)e3" 
 66      assert value_str(12356.7,7660) == "12.4(77)e3" 
 67      assert value_str(1235.67,766) == "1.24(77)e3" 
 68      assert value_str(123.567,76.6) == "124(77)" 
 69      assert value_str(12.3567,7.66) == "12.4(77)" 
 70      assert value_str(1.23567,.766) == "1.24(77)" 
 71      assert value_str(.123567,.0766) == "0.124(77)" 
 72      assert value_str(.0123567,.00766) == "0.0124(77)" 
 73      assert value_str(.00123567,.000766) == "0.00124(77)" 
 74      assert value_str(.000123567,.0000766) == "124(77)e-6" 
 75      assert value_str(.0000123567,.00000766) == "12.4(77)e-6" 
 76      assert value_str(.00000123567,.000000766) == "1.24(77)e-6" 
 77      assert value_str(.000000123567,.0000000766) == "124(77)e-9" 
 78      assert value_str(.00000123567,.0000000766) == "1.236(77)e-6" 
 79      assert value_str(.0000123567,.0000000766) == "12.357(77)e-6" 
 80      assert value_str(.000123567,.0000000766) == "123.567(77)e-6" 
 81      assert value_str(.00123567,.000000766) == "0.00123567(77)" 
 82      assert value_str(.0123567,.00000766) == "0.0123567(77)" 
 83      assert value_str(.123567,.0000766) == "0.123567(77)" 
 84      assert value_str(1.23567,.000766) == "1.23567(77)" 
 85      assert value_str(12.3567,.00766) == "12.3567(77)" 
 86      assert value_str(123.567,.0764) == "123.567(76)" 
 87      assert value_str(1235.67,.764) == "1235.67(76)" 
 88      assert value_str(12356.7,7.64) == "12356.7(76)" 
 89      assert value_str(123567,76.4) == "123567(76)" 
 90      assert value_str(1235670,764) == "1.23567(76)e6" 
 91      assert value_str(12356700,764) == "12.3567(76)e6" 
 92      assert value_str(123567000,7640) == "123.567(76)e6" 
 93      assert value_str(1235670000,76400) == "1.23567(76)e9" 
 94   
 95      # val_place == err_place 
 96      assert value_str(123567,764000) == "0.12(76)e6" 
 97      assert value_str(12356.7,76400) == "12(76)e3" 
 98      assert value_str(1235.67,7640) == "1.2(76)e3" 
 99      assert value_str(123.567,764) == "0.12(76)e3" 
100      assert value_str(12.3567,76.4) == "12(76)" 
101      assert value_str(1.23567,7.64) == "1.2(76)" 
102      assert value_str(.123567,.764) == "0.12(76)" 
103      assert value_str(.0123567,.0764) == "12(76)e-3" 
104      assert value_str(.00123567,.00764) == "1.2(76)e-3" 
105      assert value_str(.000123567,.000764) == "0.12(76)e-3" 
106   
107      # val_place == err_place-1 
108      assert value_str(123567,7640000) == "0.1(76)e6" 
109      assert value_str(12356.7,764000) == "0.01(76)e6" 
110      assert value_str(1235.67,76400) == "0.001(76)e6" 
111      assert value_str(123.567,7640) == "0.1(76)e3" 
112      assert value_str(12.3567,764) == "0.01(76)e3" 
113      assert value_str(1.23567,76.4) == "0.001(76)e3" 
114      assert value_str(.123567,7.64) == "0.1(76)" 
115      assert value_str(.0123567,.764) == "0.01(76)" 
116      assert value_str(.00123567,.0764) == "0.001(76)" 
117      assert value_str(.000123567,.00764) == "0.1(76)e-3" 
118   
119      # val_place == err_place-2 
120      assert value_str(12356700,7640000000) == "0.0(76)e9" 
121      assert value_str(1235670,764000000) == "0.00(76)e9" 
122      assert value_str(123567,76400000) == "0.000(76)e9" 
123      assert value_str(12356,7640000) == "0.0(76)e6" 
124      assert value_str(1235,764000) == "0.00(76)e6" 
125      assert value_str(123,76400) == "0.000(76)e6" 
126      assert value_str(12,7640) == "0.0(76)e3" 
127      assert value_str(1,764) == "0.00(76)e3" 
128      assert value_str(0.1,76.4) == "0.000(76)e3" 
129      assert value_str(0.01,7.64) == "0.0(76)" 
130      assert value_str(0.001,0.764) == "0.00(76)" 
131      assert value_str(0.0001,0.0764) == "0.000(76)" 
132      assert value_str(0.00001,0.00764) == "0.0(76)e-3" 
133   
134      # val_place == err_place-3 
135      assert value_str(12356700,76400000000) == "0.000(76)e12" 
136      assert value_str(1235670,7640000000) == "0.0(76)e9" 
137      assert value_str(123567,764000000) == "0.00(76)e9" 
138      assert value_str(12356,76400000) == "0.000(76)e9" 
139      assert value_str(1235,7640000) == "0.0(76)e6" 
140      assert value_str(123,764000) == "0.00(76)e6" 
141      assert value_str(12,76400) == "0.000(76)e6" 
142      assert value_str(1,7640) == "0.0(76)e3" 
143      assert value_str(0.1,764) == "0.00(76)e3" 
144      assert value_str(0.01,76.4) == "0.000(76)e3" 
145      assert value_str(0.001,7.64) == "0.0(76)" 
146      assert value_str(0.0001,0.764) == "0.00(76)" 
147      assert value_str(0.00001,0.0764) == "0.000(76)" 
148      assert value_str(0.000001,0.00764) == "0.0(76)e-3" 
149   
150      # negative values 
151      assert value_str(-1235670,765000) == "-1.24(77)e6" 
152      assert value_str(-1.23567,.765) == "-1.24(77)" 
153      assert value_str(-.00000123567,.0000000765) == "-1.236(77)e-6" 
154      assert value_str(-12356.7,7.64) == "-12356.7(76)" 
155      assert value_str(-123.567,764) == "-0.12(76)e3" 
156      assert value_str(-1235.67,76400) == "-0.001(76)e6" 
157      assert value_str(-.000123567,.00764) == "-0.1(76)e-3" 
158      assert value_str(-12356,7640000) == "-0.0(76)e6" 
159      assert value_str(-12,76400) == "-0.000(76)e6" 
160      assert value_str(-0.0001,0.764) == "-0.00(76)" 
161   
162   
163  if __name__ == "__main__": test() 
164