X-Git-Url: http://git.tremily.us/?p=hooke.git;a=blobdiff_plain;f=hooke%2Futil%2Fsi.py;h=67366c135eb094eb51550949aaa2c349b0fb791c;hp=ebb3c1927fa1983efde21bedbc2006aa8c62e797;hb=HEAD;hpb=c87a4adaaffea5fa1be53a7289d10215c5b3e483

diff --git a/hooke/util/si.py b/hooke/util/si.py
index ebb3c19..67366c1 100644
--- a/hooke/util/si.py
+++ b/hooke/util/si.py
@@ -1,163 +1,202 @@
-# Copyright
-
-"""Define functions for handling numbers in SI notation.
-
-Notes
------
-To output a scale, choose any value on the axis and find the
-multiplier and prefix for it.  Use those to format the rest of the
-scale.  As values can span several orders of magnitude, you have
-to decide what units to use.
-
->>> xs = (985e-12, 1e-9, 112358e-12)
-
-Get the power from the first (or last, or middle, ...) value
-
->>> p = get_power(xs[0])
->>> for x in xs:
-...     print ppSI(x, decimals=2, power=p)
-985.00 p
-1000.00 p
-112358.00 p
->>> print prefix_from_value(xs[0]) + 'N'
-pN
-"""
-
-import math
-from numpy import isnan
-import re
-
-
-PREFIX = {
-    24: 'Y',
-    21: 'Z',
-    18: 'E',
-    15: 'P',
-    12: 'T',
-    9: 'G',
-    6: 'M',
-    3: 'k',
-    0: '',
-    -3: 'm',
-    -6: u'\u00B5',
-    -9: 'n',
-    -12: 'p',
-    -15: 'f',
-    -18: 'a',
-    -21: 'z',
-    -24: 'y',
-    }
-"""A dictionary of SI prefixes from 10**24 to 10**-24.
-
-Examples
---------
->>> PREFIX[0]
-''
->>> PREFIX[6]
-'M'
->>> PREFIX[-9]
-'n'
-"""
-
-_DATA_LABEL_REGEXP = re.compile('^([^(]*[^ ]) ?\(([^)]*)\)$')
-"""Used by :func:`data_label_unit`.
-"""
-
-
-def ppSI(value, unit='', decimals=None, power=None, pad=False):
-    """Pretty-print `value` in SI notation.
-
-    The current implementation ignores `pad` if `decimals` is `None`.
-
-    Examples
-    --------
-    >>> x = math.pi * 1e-8
-    >>> print ppSI(x, 'N')
-    31.415927 nN
-    >>> print ppSI(x, 'N', 3)
-    31.416 nN
-    >>> print ppSI(x, 'N', 4, power=-12)
-    31415.9265 pN
-    >>> print ppSI(x, 'N', 5, pad=True)
-       31.41593 nN
-
-    If you want the decimal indented by six spaces with `decimal=2`,
-    `pad` should be the sum of
-
-    * 6 (places before the decimal point)
-    * 1 (length of the decimal point)
-    * 2 (places after the decimal point)
-
-    >>> print ppSI(-x, 'N', 2, pad=(6+1+2))
-       -31.42 nN
-    """
-    if value == 0:
-        return '0'
-    if isnan(value):
-        return 'NaN'
-
-    if power == None:  # auto-detect power
-        power = get_power(value)
-
-    if decimals == None:
-        format = lambda n: '%f' % n
-    else:
-        if pad == False:  # no padding
-            format = lambda n: '%.*f' % (decimals, n)            
-        else:
-            if pad == True:  # auto-generate pad
-                # 1 for ' ', 1 for '-', 3 for number, 1 for '.', and decimals.
-                pad = 6 + decimals
-            format = lambda n: '%*.*f' % (pad, decimals, n)
-    return '%s %s%s' % (format(value / pow(10,power)), PREFIX[power], unit)
-
-
-def get_power(value):
-    """Return the SI power for which `0 <= |value|/10**pow < 1000`. 
-    
-    Exampes
-    -------
-    >>> get_power(0)
-    0
-    >>> get_power(123)
-    0
-    >>> get_power(-123)
-    0
-    >>> get_power(1e8)
-    6
-    >>> get_power(1e-16)
-    -18
-    """
-    if value != 0 and not isnan(value):
-        # get log10(|value|)
-        value_temp = math.floor(math.log10(math.fabs(value)))
-        # reduce the log10 to a multiple of 3
-        return int(value_temp - (value_temp % 3))
-    else:
-        return 0
-
-def prefix_from_value(value):
-    """Determine the SI power of `value` and return its prefix.
-
-    Examples
-    --------
-    >>> prefix_from_value(0)
-    ''
-    >>> prefix_from_value(1e10)
-    'G'
-    """
-    return PREFIX[get_power(value)]
-
-def split_data_label(label):
-    """Split `curve.data[i].info['name']` labels into `(name, unit)`.
-
-    Examples
-    --------
-    >>> split_data_label('z piezo (m)')
-    ('z piezo', 'm')
-    >>> split_data_label('deflection (N)')
-    ('deflection', 'N')
-    """
-    m = _DATA_LABEL_REGEXP.match(label)
-    assert m != None, label
-    return m.groups()
+# Copyright (C) 2010-2012 W. Trevor King <wking@tremily.us>
+#
+# This file is part of Hooke.
+#
+# Hooke is free software: you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option) any
+# later version.
+#
+# Hooke is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with Hooke.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Define functions for handling numbers in SI notation.
+
+Notes
+-----
+To output a scale, choose any value on the axis and find the
+multiplier and prefix for it.  Use those to format the rest of the
+scale.  As values can span several orders of magnitude, you have
+to decide what units to use.
+
+>>> xs = (985e-12, 1e-9, 112358e-12)
+
+Get the power from the first (or last, or middle, ...) value
+
+>>> p = get_power(xs[0])
+>>> for x in xs:
+...     print(ppSI(x, decimals=2, power=p))
+985.00 p
+1000.00 p
+112358.00 p
+>>> print(prefix_from_value(xs[0]) + 'N')
+pN
+"""
+
+import math
+from numpy import isnan
+import re
+
+
+PREFIX = {
+    24: 'Y',
+    21: 'Z',
+    18: 'E',
+    15: 'P',
+    12: 'T',
+    9: 'G',
+    6: 'M',
+    3: 'k',
+    0: '',
+    -3: 'm',
+    -6: u'\u00B5',
+    -9: 'n',
+    -12: 'p',
+    -15: 'f',
+    -18: 'a',
+    -21: 'z',
+    -24: 'y',
+    }
+"""A dictionary of SI prefixes from 10**24 to 10**-24.
+
+Examples
+--------
+>>> PREFIX[0]
+''
+>>> PREFIX[6]
+'M'
+>>> PREFIX[-9]
+'n'
+"""
+
+_DATA_LABEL_REGEXP = re.compile('^([^(]*[^ ]) ?\(([^)]*)\)$')
+"""Used by :func:`data_label_unit`.
+"""
+
+
+def ppSI(value, unit='', decimals=None, power=None, pad=False):
+    """Pretty-print `value` in SI notation.
+
+    The current implementation ignores `pad` if `decimals` is `None`.
+
+    Examples
+    --------
+    >>> x = math.pi * 1e-8
+    >>> print(ppSI(x, 'N'))
+    31.415927 nN
+    >>> print(ppSI(x, 'N', 3))
+    31.416 nN
+    >>> print(ppSI(x, 'N', 4, power=-12))
+    31415.9265 pN
+    >>> print(ppSI(x, 'N', 5, pad=True))
+       31.41593 nN
+
+    If you want the decimal indented by six spaces with `decimal=2`,
+    `pad` should be the sum of
+
+    * 6 (places before the decimal point)
+    * 1 (length of the decimal point)
+    * 2 (places after the decimal point)
+
+    >>> print(ppSI(-x, 'N', 2, pad=(6+1+2)))
+       -31.42 nN
+    """
+    if value == 0:
+        return '0'
+    if value == None or isnan(value):
+        return 'nan'
+
+    if power == None:  # auto-detect power
+        power = get_power(value)
+
+    if decimals == None:
+        format = lambda n: '%f' % n
+    else:
+        if pad == False:  # no padding
+            format = lambda n: '%.*f' % (decimals, n)            
+        else:
+            if pad == True:  # auto-generate pad
+                # 1 for ' ', 1 for '-', 3 for number, 1 for '.', and decimals.
+                pad = 6 + decimals
+            format = lambda n: '%*.*f' % (pad, decimals, n)
+    try:
+        prefix = ' '+PREFIX[power]
+    except KeyError:
+        prefix = 'e%d ' % power
+    return '%s%s%s' % (format(value / pow(10,power)), prefix, unit)
+
+
+def get_power(value):
+    """Return the SI power for which `0 <= |value|/10**pow < 1000`. 
+    
+    Exampes
+    -------
+    >>> get_power(0)
+    0
+    >>> get_power(123)
+    0
+    >>> get_power(-123)
+    0
+    >>> get_power(1e8)
+    6
+    >>> get_power(1e-16)
+    -18
+    """
+    if value != 0 and not isnan(value):
+        # get log10(|value|)
+        value_temp = math.floor(math.log10(math.fabs(value)))
+        # reduce the log10 to a multiple of 3
+        return int(value_temp - (value_temp % 3))
+    else:
+        return 0
+
+def prefix_from_value(value):
+    """Determine the SI power of `value` and return its prefix.
+
+    Examples
+    --------
+    >>> prefix_from_value(0)
+    ''
+    >>> prefix_from_value(1e10)
+    'G'
+    """
+    return PREFIX[get_power(value)]
+
+def join_data_label(name, unit):
+    """Create laels for `curve.data[i].info['columns']`.
+
+    See Also
+    --------
+    split_data_label
+
+    Examples
+    --------
+    >>> join_data_label('z piezo', 'm')
+    'z piezo (m)'
+    >>> join_data_label('deflection', 'N')
+    'deflection (N)'
+    """
+    return '%s (%s)' % (name, unit)
+
+def split_data_label(label):
+    """Split `curve.data[i].info['columns']` labels into `(name, unit)`.
+
+    See Also
+    --------
+    join_data_label
+
+    Examples
+    --------
+    >>> split_data_label('z piezo (m)')
+    ('z piezo', 'm')
+    >>> split_data_label('deflection (N)')
+    ('deflection', 'N')
+    """
+    m = _DATA_LABEL_REGEXP.match(label)
+    assert m != None, label
+    return m.groups()