source: trunk/GSASIIpy3.py @ 1183

Last change on this file since 1183 was 1183, checked in by toby, 8 years ago

fixup number formatting; update produced doc files

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Line 
1'''
2*GSASIIpy3: Python 3.x Routines*
3================================
4
5Module to hold python 3-compatible code, to keep it separate from
6code that will break with __future__ options.
7
8'''
9from __future__ import division
10import numpy as np
11import GSASIIpath
12GSASIIpath.SetVersionNumber("$Revision: 1183 $")
13# de
14sind = sin = s = lambda x: np.sin(x*np.pi/180.)
15cosd = cos = c = lambda x: np.cos(x*np.pi/180.)
16tand = tan = t = lambda x: np.tan(x*np.pi/180.)
17sqrt = sq = lambda x: np.sqrt(x)
18pi = np.pi
19
20def FormulaEval(string):
21    '''Evaluates a algebraic formula into a float, if possible. Works
22    properly on fractions e.g. 2/3 only with python 3.0+ division.
23
24    Expressions such as 2/3, 3*pi, sin(45)/2, 2*sqrt(2), 2**10 can all
25    be evaluated.
26
27    :param str string: Character string containing a Python expression
28      to be evaluated.
29
30    :returns: the value for the expression as a float or None if the expression does not
31      evaluate to a valid number.
32   
33    '''
34    try:
35        val = float(eval(string))
36        if np.isnan(val) or np.isinf(val): return None
37    except:
38        return None
39    return val
40
41def FormatValue(val,maxdigits=None):
42    '''Format a float to fit in ``maxdigits[0]`` spaces with maxdigits[1] after decimal.
43
44    :param float val: number to be formatted.
45
46    :param list maxdigits: the number of digits & places after decimal to be used for display of the
47      number (defaults to [10,2]).
48
49    :returns: a string with <= maxdigits characters (I hope). 
50    '''
51    if maxdigits is None:
52        digits = [10,2]
53    else:
54        digits = maxdigits
55    # does the standard str() conversion fit?
56    string = str(val)
57    if len(string) <= digits[0]: return string.strip()
58    # negative numbers, leave room for a sign
59    if val < 0: digits[0] -= 1
60    decimals = digits[0] - digits[1]
61    if abs(val) < 1e-99 or abs(val) > 1e99:
62        decimals = min(digits[0]-6,digits[1])
63        fmt = "{" + (":{:d}.{:d}g".format(digits[0],decimals))+"}" # create format string
64    elif abs(val) < 1e-9 or abs(val) > 1e9:
65        decimals = min(digits[0]-5,digits[1])
66        fmt = "{" + (":{:d}.{:d}g".format(digits[0],decimals))+"}"
67    elif abs(val) < 10**(4-decimals): # make sure at least 4 decimals show
68        decimals = min(digits[0]-5,digits[1])
69        fmt = "{" + (":{:d}.{:d}g".format(digits[0],decimals))+"}"
70    elif abs(val) >= 10**decimals: # deal with large numbers in smaller spaces
71        decimals = min(digits[0]-5,digits[1])
72        fmt = "{" + (":{:d}.{:d}g".format(digits[0],decimals))+"}"
73    elif abs(val) < 1: # use f format for small numbers
74        decimals = min(digits[0]-3,digits[1])
75        fmt = "{" + (":{:d}.{:d}f".format(digits[0],decimals))+"}"
76    else: # in range where g formatting should do what I want
77        decimals = digits[0] - 1
78        fmt = "{" + (":{:d}.{:d}g".format(digits[0],decimals))+"}"
79    try:
80        return fmt.format(val).strip()
81    except ValueError as err:
82        print 'FormatValue Error with val,maxdigits,fmt=',val,maxdigits,fmt
83        return str(val)
84
85def FormatSigFigs(val, maxdigits=10, sigfigs=5, treatAsZero=1e-20):
86    '''Format a float to use ``maxdigits`` or fewer digits with ``sigfigs``
87    significant digits showing (if room allows).
88
89    :param float val: number to be formatted.
90
91    :param int maxdigits: the number of digits to be used for display of the
92       number (defaults to 10).
93
94    :param int sigfigs: the number of significant figures to use, if room allows
95
96    :param float treatAsZero: numbers that are less than this in magnitude
97      are treated as zero. Defaults to 1.0e-20, but this can be disabled
98      if set to None.
99
100    :returns: a string with <= maxdigits characters (I hope). 
101    '''
102    if treatAsZero is not None:
103        if abs(val) < treatAsZero:
104            return '0.0'
105    # negative numbers, leave room for a sign
106    if val < 0: maxdigits -= 1
107    if abs(val) < 1e-99 or abs(val) > 9.999e99:
108        decimals = min(maxdigits-6,sigfigs)
109        fmt = "{" + (":{:d}.{:d}g".format(maxdigits,decimals))+"}" # create format string
110    elif abs(val) < 1e-9 or abs(val) > 9.999e9:
111        decimals = min(maxdigits-5,sigfigs)
112        fmt = "{" + (":{:d}.{:d}g".format(maxdigits,decimals))+"}"
113    elif abs(val) < 9.9999999*10**(sigfigs-maxdigits):
114        decimals = min(maxdigits-5,sigfigs)
115        fmt = "{" + (":{:d}.{:d}g".format(maxdigits,decimals))+"}"
116    elif abs(val) >= 10**sigfigs: # deal with large numbers in smaller spaces
117        decimals = min(maxdigits-5,sigfigs)
118        fmt = "{" + (":{:d}.{:d}g".format(maxdigits,decimals))+"}"
119    elif abs(val) < 1: # small numbers, add to decimal places
120        decimals = sigfigs - int(np.log10(abs(val)))
121        fmt = "{" + (":{:d}.{:d}f".format(maxdigits,decimals))+"}"
122    else: # larger numbers, remove decimal places
123        decimals = sigfigs - 1 - int(np.log10(abs(val)))
124        fmt = "{" + (":{:d}.{:d}f".format(maxdigits,decimals))+"}"
125        if decimals == 0: fmt += "." # force a decimal place
126    try:
127        return fmt.format(val).strip()
128    except ValueError as err:
129        print 'FormatValue Error with val,maxdigits, sigfigs, fmt=',val, maxdigits,sigfigs, fmt
130        return str(val)
131
132if __name__ == '__main__':
133    for i in (1.23456789e-129,1.23456789e129,1.23456789e-99,1.23456789e99,-1.23456789e-99,-1.23456789e99):
134        print FormatSigFigs(i),i
135    for i in (1,10,100,1000,10000,100000,1000000,10000000,100000000,1000000000):
136        print FormatSigFigs(1.23456789e-9*i),1.23456789e-9*i
137    for i in (1,10,100,1000,10000,100000,1000000,10000000,100000000):
138        print FormatSigFigs(1.23456789e9/i),1.23456789e9/i
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