source: trunk/GSASIIpy3.py @ 1410

Last change on this file since 1410 was 1410, checked in by toby, 7 years ago

fix number formatting in FormatValue? to be closer to Fortran, but always display a valid number, perhaps with few sig figs

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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: 1410 $")
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 FormatPadValue(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 exactly maxdigits[0] characters (except under error conditions),
50      but last character will always be a space
51    '''
52    if maxdigits is None:
53        digits = [10,2]
54    else:
55        digits = list(maxdigits)
56    fmt = '{:'+str(digits[0])+'}'
57    s = fmt.format(FormatValue(val,digits))
58    if s[-1] == ' ':
59        return s
60    else:
61        return s+' '
62   
63
64def FormatValue(val,maxdigits=None):
65    '''Format a float to fit in at most ``maxdigits[0]`` spaces with maxdigits[1] after decimal.
66    Note that this code has been hacked from FormatSigFigs and may have unused sections.
67
68    :param float val: number to be formatted.
69
70    :param list maxdigits: the number of digits & places after decimal to be used for display of the
71      number (defaults to [10,2]).
72
73    :returns: a string with <= maxdigits characters (usually). 
74    '''
75    if maxdigits is None:
76        digits = [10,2]
77    else:
78        digits = list(maxdigits)
79    string = ("{:."+str(digits[1])+"f}").format(val).strip() # will standard .f formatting work?
80    if len(string) <= digits[0]:
81        if digits[1] > 0: # strip off extra zeros on right side
82            string = string.rstrip('0')
83            if string[-1] == '.': string += "0"
84        return string
85    if val < 0: digits[0] -= 1 # negative numbers, reserve space for the sign
86    decimals = digits[0] - digits[1]
87    if abs(val) > 1e99: # for very large numbers, use scientific notation and use all digits
88        fmt = "{" + (":{:d}.{:d}g".format(digits[0],digits[0]-6))+"}"
89    elif abs(val) > 1e9:
90        fmt = "{" + (":{:d}.{:d}g".format(digits[0],digits[0]-5))+"}"
91    elif abs(val) < 10**(4-decimals): # make sure at least 4 decimals show
92        # this clause is probably no longer needed since the number probably shows as 0.0
93        decimals = min(digits[0]-5,digits[1])
94        fmt = "{" + (":{:d}.{:d}g".format(digits[0],decimals))+"}"
95    elif abs(val) >= 10**(decimals-1): # deal with large numbers in smaller spaces
96        decimals = max(0,digits[0]-5)
97        fmt = "{" + (":{:d}.{:d}g".format(digits[0],decimals))+"}"
98    elif abs(val) < 1: # use f format for small numbers
99        # this clause is probably no longer needed since the number probably shows as 0.0
100        decimals = min(digits[0]-3,digits[1])
101        fmt = "{" + (":{:d}.{:d}f".format(digits[0],decimals))+"}"
102    else: # in range where g formatting should do what I want
103        # used?
104        decimals = digits[0] - 1
105        fmt = "{" + (":{:d}.{:d}g".format(digits[0],decimals))+"}"
106    try:
107        return fmt.format(float(val)).strip()
108    except ValueError as err:
109        print 'FormatValue Error with val,maxdigits,fmt=',val,maxdigits,fmt
110        return str(val)
111
112def FormatSigFigs(val, maxdigits=10, sigfigs=5, treatAsZero=1e-20):
113    '''Format a float to use ``maxdigits`` or fewer digits with ``sigfigs``
114    significant digits showing (if room allows).
115
116    :param float val: number to be formatted.
117
118    :param int maxdigits: the number of digits to be used for display of the
119       number (defaults to 10).
120
121    :param int sigfigs: the number of significant figures to use, if room allows
122
123    :param float treatAsZero: numbers that are less than this in magnitude
124      are treated as zero. Defaults to 1.0e-20, but this can be disabled
125      if set to None.
126
127    :returns: a string with <= maxdigits characters (I hope). 
128    '''
129    if treatAsZero is not None:
130        if abs(val) < treatAsZero:
131            return '0.0'
132    # negative numbers, leave room for a sign
133    if val < 0: maxdigits -= 1
134    if abs(val) < 1e-99 or abs(val) > 9.999e99:
135        decimals = min(maxdigits-6,sigfigs)
136        fmt = "{" + (":{:d}.{:d}g".format(maxdigits,decimals))+"}" # create format string
137    elif abs(val) < 1e-9 or abs(val) > 9.999e9:
138        decimals = min(maxdigits-5,sigfigs)
139        fmt = "{" + (":{:d}.{:d}g".format(maxdigits,decimals))+"}"
140    elif abs(val) < 9.9999999*10**(sigfigs-maxdigits):
141        decimals = min(maxdigits-5,sigfigs)
142        fmt = "{" + (":{:d}.{:d}g".format(maxdigits,decimals))+"}"
143    elif abs(val) >= 10**sigfigs: # deal with large numbers in smaller spaces
144        decimals = min(maxdigits-5,sigfigs)
145        fmt = "{" + (":{:d}.{:d}g".format(maxdigits,decimals))+"}"
146    elif abs(val) < 1: # small numbers, add to decimal places
147        decimals = sigfigs - int(np.log10(abs(val)))
148        fmt = "{" + (":{:d}.{:d}f".format(maxdigits,decimals))+"}"
149    else: # larger numbers, remove decimal places
150        decimals = sigfigs - 1 - int(np.log10(abs(val)))
151        if decimals <= 0: 
152            fmt = "{" + (":{:d}.0f".format(maxdigits))+"}."
153        else:
154            fmt = "{" + (":{:d}.{:d}f".format(maxdigits,decimals))+"}"
155    try:
156        return fmt.format(float(val)).strip()
157    except ValueError as err:
158        print 'FormatValue Error with val,maxdigits, sigfigs, fmt=',val, maxdigits,sigfigs, fmt
159        return str(val)
160
161if __name__ == '__main__':
162    for i in (1.23456789e-129,1.23456789e129,1.23456789e-99,1.23456789e99,-1.23456789e-99,-1.23456789e99):
163        print FormatSigFigs(i),i
164    for i in (1,10,100,1000,10000,100000,1000000,10000000,100000000,1000000000):
165        print FormatSigFigs(1.23456789e-9*i),1.23456789e-9*i
166    for i in (1,10,100,1000,10000,100000,1000000,10000000,100000000):
167        print FormatSigFigs(1.23456789e9/i),1.23456789e9/i
168
169    print FormatSigFigs(200,10,3)
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