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# -*- coding: utf-8 -*-
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"""Modify the PhysicalQuantities class for more convenient interactive use.
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Also redefine some math functions to operate on PhysQties with no need for
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special method syntax. This just means moving them out to the global
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namespace.
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This module should always be loaded *after* math or Numeric, so it can
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overwrite math functions with the versions that handle units.
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Authors
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-------
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- Fernando Perez <Fernando.Perez@berkeley.edu>
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"""
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#*****************************************************************************
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# Copyright (C) 2008-2011 The IPython Development Team
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# Copyright (C) 2001-2007 Fernando Perez <fperez@colorado.edu>
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#
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# Distributed under the terms of the BSD License. The full license is in
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# the file COPYING, distributed as part of this software.
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#*****************************************************************************
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from Scientific.Physics.PhysicalQuantities import PhysicalQuantity
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# This code can be set up to work with Numeric or with math for providing the
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# mathematical functions. Uncomment the one you prefer to use below.
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# If you use math, sin(x) won't work for x an array, only float or PhysQty
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import math
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# If you use Numeric, sin(x) works for x a float, PhysQty an array.
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#import Numeric as math
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class PhysicalQuantityFunction:
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"""Generic function wrapper for PhysicalQuantity instances.
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Calls functions from either the math library or the instance's methods as
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required. Allows using sin(theta) or sqrt(v**2) syntax irrespective of
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whether theta is a pure number or a PhysicalQuantity.
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This is *slow*. It's meant for convenient interactive use, not for
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speed."""
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def __init__(self,name):
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self.name = name
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def __call__(self,x):
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if isinstance(x,PhysicalQuantity):
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return PhysicalQuantity.__dict__[self.name](x)
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else:
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return math.__dict__[self.name](x)
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class PhysicalQuantityInteractive(PhysicalQuantity):
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"""Physical quantity with units - modified for Interactive use.
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Basically, the __str__ and __repr__ methods have been swapped for more
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convenient interactive use. Powers are shown as ^ instead of ** and only 4
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significant figures are shown.
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Also adds the following aliases for commonly used methods:
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b = PhysicalQuantity.inBaseUnits
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u = PhysicalQuantity.inUnitsOf
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These are useful when doing a lot of interactive calculations.
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"""
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# shorthands for the most useful unit conversions
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b = PhysicalQuantity.inBaseUnits # so you can just type x.b to get base units
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u = PhysicalQuantity.inUnitsOf
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# This can be done, but it can get dangerous when coupled with IPython's
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# auto-calling. Everything ends up shown in baseunits and things like x*2
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# get automatically converted to k(*2), which doesn't work.
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# Probably not a good idea in general...
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#__call__ = b
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def __str__(self):
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return PhysicalQuantity.__repr__(self)
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def __repr__(self):
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value = '%.4G' % self.value
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units = self.unit.name().replace('**','^')
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return value + ' ' + units
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# implement the methods defined in PhysicalQuantity as PhysicalQuantityFunctions
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sin = PhysicalQuantityFunction('sin')
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cos = PhysicalQuantityFunction('cos')
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tan = PhysicalQuantityFunction('tan')
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sqrt = PhysicalQuantityFunction('sqrt')
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