dimensions Package Documentation

This page contains the dimensions Package documentation.

The DictWithDefault Module

The NumberDict Module

The physicalField Module

Physical quantities with units.

This module derives from Konrad Hinsen‘s PhysicalQuantity <http://dirac.cnrs-orleans.fr/ScientificPython/ScientificPythonManual/Scientific.Physics.PhysicalQuantities-module.html>.

This module provides a data type that represents a physical quantity together with its unit. It is possible to add and subtract these quantities if the units are compatible, and a quantity can be converted to another compatible unit. Multiplication, subtraction, and raising to integer powers is allowed without restriction, and the result will have the correct unit. A quantity can be raised to a non-integer power only if the result can be represented by integer powers of the base units.

The values of physical constants are taken from the 2002 recommended values from CODATA. Other conversion factors (e.g. for British units) come from Appendix B of NIST Special Publication 811.

Warning

We can’t guarantee for the correctness of all entries in the unit table, so use this at your own risk!

Base SI units:

m, kg, s, A, K, mol, cd, rad, sr

SI prefixes:

 Y = 1e+24
 Z = 1e+21
 E = 1e+18
 P = 1e+15
 T = 1e+12
 G = 1e+09
 M = 1e+06
 k = 1000
 h = 100
da = 10
 d = 0.1
 c = 0.01
 m = 0.001
mu = 1e-06
 n = 1e-09
 p = 1e-12
 f = 1e-15
 a = 1e-18
 z = 1e-21
 y = 1e-24

Units derived from SI (accepting SI prefixes):

  1 Bq = 1 1/s
   1 C = 1 A*s
1 degC = 1 K
   1 F = 1 A**2*s**4/kg/m**2
  1 Gy = 1 m**2/s**2
   1 H = 1 kg*m**2/A**2/s**2
  1 Hz = 1 1/s
   1 J = 1 m**2*kg/s**2
  1 lm = 1 sr*cd
  1 lx = 1 sr*cd/m**2
   1 N = 1 m*kg/s**2
 1 ohm = 1 kg*m**2/A**2/s**3
  1 Pa = 1 kg/s**2/m
   1 S = 1 A**2*s**3/kg/m**2
  1 Sv = 1 m**2/s**2
   1 T = 1 kg/A/s**2
   1 V = 1 kg*m**2/A/s**3
   1 W = 1 m**2*kg/s**3
  1 Wb = 1 kg*m**2/A/s**2

Other units that accept SI prefixes:

1 eV = 1.60217653e-19 m**2*kg/s**2

Additional units and constants:

  1 acres = 4046.8564224 m**2
    1 amu = 1.6605402e-27 kg
    1 Ang = 1e-10 m
    1 atm = 101325.0 kg/s**2/m
      1 b = 1e-28 m
    1 bar = 100000.0 kg/s**2/m
   1 Bohr = 5.29177208115e-11 m
   1 Btui = 1055.05585262 m**2*kg/s**2
      1 c = 299792458.0 m/s
    1 cal = 4.184 m**2*kg/s**2
   1 cali = 4.1868 m**2*kg/s**2
     1 cl = 1e-05 m**3
    1 cup = 0.000236588256 m**3
      1 d = 86400.0 s
    1 deg = 0.0174532925199 rad
   1 degF = 0.555555555556 K
   1 degR = 0.555555555556 K
     1 dl = 0.0001 m**3
    1 dyn = 1e-05 m*kg/s**2
      1 e = 1.60217653e-19 A*s
   1 eps0 = 8.85418781762e-12 A**2*s**4/kg/m**3
    1 erg = 1e-07 m**2*kg/s**2
   1 floz = 2.9573532e-05 m**3
     1 ft = 0.3048 m
      1 g = 0.001 kg
  1 galUK = 0.00454609 m**3
  1 galUS = 0.003785412096 m**3
     1 gn = 9.80665 m/s**2
   1 Grav = 6.6742e-11 m**3/s**2/kg
      1 h = 3600.0 s
     1 ha = 10000.0 m**2
1 Hartree = 4.3597441768e-18 m**2*kg/s**2
   1 hbar = 1.05457168236e-34 m**2*kg/s
   1 hpEl = 746.0 m**2*kg/s**3
1 hplanck = 6.6260693e-34 m**2*kg/s
   1 hpUK = 745.7 m**2*kg/s**3
   1 inch = 0.0254 m
  1 invcm = 1.98644560233e-23 m**2*kg/s**2
     1 kB = 1.3806505e-23 kg*m**2/s**2/K
   1 kcal = 4184.0 m**2*kg/s**2
  1 kcali = 4186.8 m**2*kg/s**2
    1 Ken = 1.3806505e-23 m**2*kg/s**2
      1 l = 0.001 m**3
     1 lb = 0.45359237 kg
    1 lyr = 9.46073047258e+15 m
     1 me = 9.1093826e-31 kg
     1 mi = 1609.344 m
    1 min = 60.0 s
     1 ml = 1e-06 m**3
     1 mp = 1.67262171e-27 kg
    1 mu0 = 1.25663706144e-06 kg*m/A**2/s**2
    1 Nav = 6.0221415e+23 1/mol
    1 nmi = 1852.0 m
     1 oz = 0.028349523125 kg
    1 psi = 6894.75729317 kg/s**2/m
     1 pt = 0.000473176512 m**3
     1 qt = 0.000946353024 m**3
   1 tbsp = 1.4786766e-05 m**3
    1 ton = 907.18474 kg
   1 Torr = 133.322368421 kg/s**2/m
    1 tsp = 4.928922e-06 m**3
     1 wk = 604800.0 s
     1 yd = 0.9144 m
     1 yr = 31536000.0 s
  1 yrJul = 31557600.0 s
  1 yrSid = 31558152.96 s

class fipy.tools.dimensions.physicalField.PhysicalField(value, unit=None, array=None)

Bases: object

Physical field or quantity with units

Physical Fields can be constructed in one of two ways:

• PhysicalField(*value*, *unit*), where *value* is a number of arbitrary type and *unit* is a string containing the unit name

  >>> print PhysicalField(value = 10., unit = 'm')
  10.0 m
  

• PhysicalField(*string*), where *string* contains both the value and the unit. This form is provided to make interactive use more convenient

  >>> print PhysicalField(value = "10. m")
  10.0 m
  

Dimensionless quantities, with a unit of 1, can be specified in several ways

>>> print PhysicalField(value = "1")
1.0 1
>>> print PhysicalField(value = 2., unit = " ")
2.0 1
>>> print PhysicalField(value = 2.)
2.0 1

Physical arrays are also possible (and are the reason this code was adapted from Konrad Hinsen‘s original PhysicalQuantity). The value can be a Numeric array:

>>> a = numerix.array(((3.,4.),(5.,6.)))
>>> print PhysicalField(value = a, unit = "m")
[[ 3.  4.]
 [ 5.  6.]] m

or a tuple:

>>> print PhysicalField(value = ((3.,4.),(5.,6.)), unit = "m")
[[ 3.  4.]
 [ 5.  6.]] m

or as a single value to be applied to every element of a supplied array:

>>> print PhysicalField(value = 2., unit = "m", array = a)
[[ 2.  2.]
 [ 2.  2.]] m

Every element in an array has the same unit, which is stored only once for the whole array.

add(other)

Add two physical quantities, so long as their units are compatible. The unit of the result is the unit of the first operand.

>>> print PhysicalField(10., 'km') + PhysicalField(10., 'm')
10.01 km
>>> print PhysicalField(10., 'km') + PhysicalField(10., 'J')
Traceback (most recent call last):
    ...
TypeError: Incompatible units

allclose(other, atol=None, rtol=1e-08)

This function tests whether or not self and other are equal subject to the given relative and absolute tolerances. The formula used is:

| self - other | < atol + rtol * | other |

This means essentially that both elements are small compared to atol or their difference divided by other‘s value is small compared to rtol.

allequal(other)

This function tests whether or not self and other are exactly equal.

arccos()

Return the inverse cosine of the PhysicalField in radians

>>> print PhysicalField(0).arccos()
1.57079632679 rad

The input PhysicalField must be dimensionless

>>> print round(PhysicalField("1 m").arccos(), 6)
Traceback (most recent call last):
    ...
TypeError: Incompatible units

arccosh()

Return the inverse hyperbolic cosine of the PhysicalField

>>> print PhysicalField(2).arccosh()
1.31695789692

The input PhysicalField must be dimensionless

>>> print round(PhysicalField("1. m").arccosh(), 6)
Traceback (most recent call last):
    ...
TypeError: Incompatible units

arcsin()

Return the inverse sine of the PhysicalField in radians

>>> print PhysicalField(1).arcsin()
1.57079632679 rad

The input PhysicalField must be dimensionless

>>> print round(PhysicalField("1 m").arcsin(), 6)
Traceback (most recent call last):
    ...
TypeError: Incompatible units

arctan()

Return the arctangent of the PhysicalField in radians

>>> print round(PhysicalField(1).arctan(), 6)
0.785398

The input PhysicalField must be dimensionless

>>> print round(PhysicalField("1 m").arctan(), 6)
Traceback (most recent call last):
    ...
TypeError: Incompatible units

arctan2(other)

Return the arctangent of self divided by other in radians

>>> print round(PhysicalField(2.).arctan2(PhysicalField(5.)), 6)
0.380506

The input PhysicalField objects must be in the same dimensions

>>> print round(PhysicalField(2.54, "cm").arctan2(PhysicalField(1., "inch")), 6)
0.785398

>>> print round(PhysicalField(2.).arctan2(PhysicalField("5. m")), 6)
Traceback (most recent call last):
    ...
TypeError: Incompatible units

arctanh()

Return the inverse hyperbolic tangent of the PhysicalField

>>> print PhysicalField(0.5).arctanh()
0.549306144334

The input PhysicalField must be dimensionless

>>> print round(PhysicalField("1 m").arctanh(), 6)
Traceback (most recent call last):
    ...
TypeError: Incompatible units

ceil()

Return the smallest integer greater than or equal to the PhysicalField.

>>> print PhysicalField(2.2,"m").ceil()
3.0 m

conjugate()

Return the complex conjugate of the PhysicalField.

>>> print PhysicalField(2.2 - 3j,"ohm").conjugate() == PhysicalField(2.2 + 3j,"ohm")
True

convertToUnit(unit)

Changes the unit to unit and adjusts the value such that the combination is equivalent. The new unit is by a string containing its name. The new unit must be compatible with the previous unit of the object.

>>> e = PhysicalField('2.7 Hartree*Nav')
>>> e.convertToUnit('kcal/mol')
>>> print e
1694.27557621 kcal/mol

copy()

Make a duplicate.

>>> a = PhysicalField(1, unit = 'inch')
>>> b = a.copy()

The duplicate will not reflect changes made to the original

>>> a.convertToUnit('cm')
>>> print a
2.54 cm
>>> print b
1 inch

Likewise for arrays

>>> a = PhysicalField(numerix.array((0,1,2)), unit  = 'm')
>>> b = a.copy()
>>> a[0] = 3
>>> print a
[3 1 2] m
>>> print b
[0 1 2] m

cos()

Return the cosine of the PhysicalField

>>> print round(PhysicalField(2*numerix.pi/6,"rad").cos(), 6)
0.5
>>> print round(PhysicalField(60.,"deg").cos(), 6)
0.5

The units of the PhysicalField must be an angle

>>> PhysicalField(60.,"m").cos()
Traceback (most recent call last):
    ...
TypeError: Incompatible units

cosh()

Return the hyperbolic cosine of the PhysicalField

>>> PhysicalField(0.).cosh()
1.0

The units of the PhysicalField must be dimensionless

>>> PhysicalField(60.,"m").cosh()
Traceback (most recent call last):
    ...
TypeError: Incompatible units

divide(other)

Divide two physical quantities. The unit of the result is the unit of the first operand divided by the unit of the second.

>>> print PhysicalField(10., 'm') / PhysicalField(2., 's')
5.0 m/s

As a special case, if the result is dimensionless, the value is returned without units, rather than with a dimensionless unit of 1. This facilitates passing physical quantities to packages such as Numeric that cannot use units, while ensuring the quantities have the desired units

>>> print (PhysicalField(1., 'inch') 
...        / PhysicalField(1., 'mm'))
25.4

dot(other)

Return the dot product of self with other. The resulting unit is the product of the units of self and other.

>>> v = PhysicalField(((5.,6.),(7.,8.)), "m")
>>> print PhysicalField(((1.,2.),(3.,4.)), "m").dot(v)
[ 26.  44.] m**2

floor()

Return the largest integer less than or equal to the PhysicalField.

>>> print PhysicalField(2.2,"m").floor()
2.0 m

getNumericValue()

Return the PhysicalField without units, after conversion to base SI units.

>>> print round(PhysicalField("1 inch").getNumericValue(), 6)
0.0254

getShape()

getUnit()

Return the unit object of self.

>>> PhysicalField("1 m").getUnit()
<PhysicalUnit m>

getsctype(default=None)

Returns the Numpy sctype of the underlying array.

>>> PhysicalField(1, 'm').getsctype() == numerix.NUMERIX.obj2sctype(numerix.array(1))
True
>>> PhysicalField(1., 'm').getsctype() == numerix.NUMERIX.obj2sctype(numerix.array(1.))
True
>>> PhysicalField((1,1.), 'm').getsctype() == numerix.NUMERIX.obj2sctype(numerix.array((1., 1.)))
True

inBaseUnits()

Return the quantity with all units reduced to their base SI elements.

>>> e = PhysicalField('2.7 Hartree*Nav')
>>> print e.inBaseUnits()
7088849.01085 kg*m**2/s**2/mol

inDimensionless()

Returns the numerical value of a dimensionless quantity.

>>> print PhysicalField(((2.,3.),(4.,5.))).inDimensionless()
[[ 2.  3.]
 [ 4.  5.]]

It’s an error to convert a quantity with units

>>> print PhysicalField(((2.,3.),(4.,5.)),"m").inDimensionless()
Traceback (most recent call last):
    ...
TypeError: Incompatible units

inRadians()

Converts an angular quantity to radians and returns the numerical value.

>>> print PhysicalField(((2.,3.),(4.,5.)),"rad").inRadians()
[[ 2.  3.]
 [ 4.  5.]]
>>> print PhysicalField(((2.,3.),(4.,5.)),"deg").inRadians()
[[ 0.03490659  0.05235988]
 [ 0.06981317  0.08726646]]

As a special case, assumes a dimensionless quantity is already in radians.

>>> print PhysicalField(((2.,3.),(4.,5.))).inRadians()
[[ 2.  3.]
 [ 4.  5.]]

It’s an error to convert a quantity with non-angular units

>>> print PhysicalField(((2.,3.),(4.,5.)),"m").inRadians()
Traceback (most recent call last):
    ...
TypeError: Incompatible units

inSIUnits()

Return the quantity with all units reduced to SI-compatible elements.

>>> e = PhysicalField('2.7 Hartree*Nav')
>>> print e.inSIUnits()
7088849.01085 kg*m**2/s**2/mol

inUnitsOf(*units)

Returns one or more PhysicalField objects that express the same physical quantity in different units. The units are specified by strings containing their names. The units must be compatible with the unit of the object. If one unit is specified, the return value is a single PhysicalField.

>>> freeze = PhysicalField('0 degC')
>>> print freeze.inUnitsOf('degF')
32.0 degF

If several units are specified, the return value is a tuple of PhysicalField instances with with one element per unit such that the sum of all quantities in the tuple equals the the original quantity and all the values except for the last one are integers. This is used to convert to irregular unit systems like hour/minute/second. The original object will not be changed.

>>> t = PhysicalField(314159., 's')
>>> [str(element) for element in t.inUnitsOf('d','h','min','s')]
['3.0 d', '15.0 h', '15.0 min', '59.0 s']

isCompatible(unit)

itemset(value)

Assign the value of a scalar array, performing appropriate conversions.

>>> a = PhysicalField(4.,"m")
>>> a.itemset(PhysicalField("6 ft"))
>>> print a
1.8288 m
>>> a = PhysicalField(((3.,4.),(5.,6.)),"m")
>>> a.itemset(PhysicalField("6 ft"))
Traceback (most recent call last):
    ...
ValueError: can only place a scalar for an  array of size 1
>>> a.itemset(PhysicalField("2 min"))
Traceback (most recent call last):
    ...
TypeError: Incompatible units

log()

Return the natural logarithm of the PhysicalField

>>> print round(PhysicalField(10).log(), 6)
2.302585

The input PhysicalField must be dimensionless

>>> print round(PhysicalField("1. m").log(), 6)
Traceback (most recent call last):
    ...
TypeError: Incompatible units

log10()

Return the base-10 logarithm of the PhysicalField

>>> print round(PhysicalField(10.).log10(), 6)
1.0

The input PhysicalField must be dimensionless

>>> print round(PhysicalField("1. m").log10(), 6)
Traceback (most recent call last):
    ...
TypeError: Incompatible units

multiply(other)

Multiply two physical quantities. The unit of the result is the product of the units of the operands.

>>> print PhysicalField(10., 'N') * PhysicalField(10., 'm')
100.0 m*N

As a special case, if the result is dimensionless, the value is returned without units, rather than with a dimensionless unit of 1. This facilitates passing physical quantities to packages such as Numeric that cannot use units, while ensuring the quantities have the desired units.

>>> print (PhysicalField(10., 's') * PhysicalField(2., 'Hz'))
20.0

put(indices, values)

put is the opposite of take. The values of self at the locations specified in indices are set to the corresponding value of values.

The indices can be any integer sequence object with values suitable for indexing into the flat form of self. The values must be any sequence of values that can be converted to the typecode of self.

>>> f = PhysicalField((1.,2.,3.),"m")
>>> f.put((2,0), PhysicalField((2.,3.),"inch"))
>>> print f
[ 0.0762  2.      0.0508] m

The units of values must be compatible with self.

>>> f.put(1, PhysicalField(3,"kg"))
Traceback (most recent call last):
    ...
TypeError: Incompatible units

reshape(shape)

Changes the shape of self to that specified in shape

>>> print PhysicalField((1.,2.,3.,4.),"m").reshape((2,2))
[[ 1.  2.]
 [ 3.  4.]] m

The new shape must have the same size as the existing one.

>>> print PhysicalField((1.,2.,3.,4.),"m").reshape((2,3))
Traceback (most recent call last):
    ...
ValueError: total size of new array must be unchanged

setUnit(unit)

Change the unit object of self to unit

>>> a = PhysicalField(value="1 m")
>>> a.setUnit("m**2/s")
>>> print a
1.0 m**2/s

shape

Tuple of array dimensions.

sign()

Return the sign of the quantity. The unit is unchanged.

>>> from fipy.tools.numerix import sign
>>> print sign(PhysicalField(((3.,-2.),(-1.,4.)), 'm'))
[[ 1. -1.]
 [-1.  1.]]

sin()

Return the sine of the PhysicalField

>>> print PhysicalField(numerix.pi/6,"rad").sin()
0.5
>>> print PhysicalField(30.,"deg").sin()
0.5

The units of the PhysicalField must be an angle

>>> PhysicalField(30.,"m").sin()
Traceback (most recent call last):
    ...
TypeError: Incompatible units

sinh()

Return the hyperbolic sine of the PhysicalField

>>> PhysicalField(0.).sinh()
0.0

The units of the PhysicalField must be dimensionless

>>> PhysicalField(60.,"m").sinh()
Traceback (most recent call last):
    ...
TypeError: Incompatible units

sqrt()

Return the square root of the PhysicalField

>>> print PhysicalField("100. m**2").sqrt()
10.0 m

The resulting unit must be integral

>>> print PhysicalField("100. m").sqrt()
Traceback (most recent call last):
    ...
TypeError: Illegal exponent

subtract(other)

Subtract two physical quantities, so long as their units are compatible. The unit of the result is the unit of the first operand.

>>> print PhysicalField(10., 'km') - PhysicalField(10., 'm')
9.99 km
>>> print PhysicalField(10., 'km') - PhysicalField(10., 'J')
Traceback (most recent call last):
    ...
TypeError: Incompatible units

sum(index=0)

Returns the sum of all of the elements in self along the specified axis (first axis by default).

>>> print PhysicalField(((1.,2.),(3.,4.)), "m").sum()
[ 4.  6.] m
>>> print PhysicalField(((1.,2.),(3.,4.)), "m").sum(1)
[ 3.  7.] m

take(indices, axis=0)

Return the elements of self specified by the elements of indices. The resulting PhysicalField array has the same units as the original.

>>> print PhysicalField((1.,2.,3.),"m").take((2,0))
[ 3.  1.] m

The optional third argument specifies the axis along which the selection occurs, and the default value (as in the example above) is 0, the first axis.

>>> print PhysicalField(((1.,2.,3.),(4.,5.,6.)),"m").take((2,0), axis = 1)
[[ 3.  1.]
 [ 6.  4.]] m

tan()

Return the tangent of the PhysicalField

>>> round(PhysicalField(numerix.pi/4,"rad").tan(), 6)
1.0
>>> round(PhysicalField(45,"deg").tan(), 6)
1.0

The units of the PhysicalField must be an angle

>>> PhysicalField(45.,"m").tan()
Traceback (most recent call last):
    ...
TypeError: Incompatible units

tanh()

Return the hyperbolic tangent of the PhysicalField

>>> print numerix.allclose(PhysicalField(1.).tanh(), 0.761594155956)
True

The units of the PhysicalField must be dimensionless

>>> PhysicalField(60.,"m").tanh()
Traceback (most recent call last):
    ...
TypeError: Incompatible units

tostring(max_line_width=75, precision=8, suppress_small=False, separator=' ')

Return human-readable form of a physical quantity

>>> p = PhysicalField(value = (3., 3.14159), unit = "eV")
>>> print p.tostring(precision = 3, separator = '|')
[ 3.   | 3.142] eV

class fipy.tools.dimensions.physicalField.PhysicalUnit(names, factor, powers, offset=0)

A PhysicalUnit represents the units of a PhysicalField.

This class is not generally not instantiated by users of this module, but rather it is created in the process of constructing a PhysicalField.

Parameters :

• names: the name of the unit
• factor: the multiplier between the unit and the fundamental SI unit
• powers: a nine-element list, tuple, or Numeric array representing the fundamental SI units of [“m”, “kg”, “s”, “A”, “K”, “mol”, “cd”, “rad”, “sr”]
• offset: the displacement between the zero-point of the unit and the zero-point of the corresponding fundamental SI unit.

conversionFactorTo(other)

Return the multiplication factor between two physical units

>>> a = PhysicalField("1. mm")
>>> b = PhysicalField("1. inch")
>>> print round(b.getUnit().conversionFactorTo(a.getUnit()), 6)
25.4

Units must have the same fundamental SI units

>>> c = PhysicalField("1. K")
>>> c.getUnit().conversionFactorTo(a.getUnit())
Traceback (most recent call last):
    ...
TypeError: Incompatible units

If units have different offsets, they must have the same factor

>>> d = PhysicalField("1. degC")
>>> c.getUnit().conversionFactorTo(d.getUnit())
1.0
>>> e = PhysicalField("1. degF")
>>> c.getUnit().conversionFactorTo(e.getUnit())
Traceback (most recent call last):
    ...
TypeError: Unit conversion (K to degF) cannot be expressed as a simple multiplicative factor

conversionTupleTo(other)

Return a tuple of the multiplication factor and offset between two physical units

>>> a = PhysicalField("1. K").getUnit()
>>> b = PhysicalField("1. degF").getUnit()
>>> [str(round(element,6)) for element in b.conversionTupleTo(a)]
['0.555556', '459.67']

isAngle()

Returns True if the unit is an angle

>>> PhysicalField("1. deg").getUnit().isAngle()
1
>>> PhysicalField("1. rad").getUnit().isAngle()
1
>>> PhysicalField("1. inch").getUnit().isAngle()
0

isCompatible(other)

Returns a list of which fundamental SI units are compatible between self and other

>>> a = PhysicalField("1. mm")
>>> b = PhysicalField("1. inch")
>>> print numerix.allclose(a.getUnit().isCompatible(b.getUnit()),
...                        [True, True, True, True, True, True, True, True, True])
True
>>> c = PhysicalField("1. K")
>>> print numerix.allclose(a.getUnit().isCompatible(c.getUnit()),
...                        [False, True, True, True, False, True, True, True, True])
True

isDimensionless()

Returns True if the unit is dimensionless

>>> PhysicalField("1. m/m").getUnit().isDimensionless()
1
>>> PhysicalField("1. inch").getUnit().isDimensionless()
0

isDimensionlessOrAngle()

Returns True if the unit is dimensionless or an angle

>>> PhysicalField("1. m/m").getUnit().isDimensionlessOrAngle()
1
>>> PhysicalField("1. deg").getUnit().isDimensionlessOrAngle()
1
>>> PhysicalField("1. rad").getUnit().isDimensionlessOrAngle()
1
>>> PhysicalField("1. inch").getUnit().isDimensionlessOrAngle()
0

isInverseAngle()

Returns True if the 1 divided by the unit is an angle

>>> PhysicalField("1. deg**-1").getUnit().isInverseAngle()
1
>>> PhysicalField("1. 1/rad").getUnit().isInverseAngle()
1
>>> PhysicalField("1. inch").getUnit().isInverseAngle()
0

name()

Return the name of the unit

>>> PhysicalField("1. m").getUnit().name()
'm'
>>> (PhysicalField("1. m") / PhysicalField("1. s") 
...  / PhysicalField("1. s")).getUnit().name()
'm/s**2'

setName(name)

Set the name of the unit to name

>>> a = PhysicalField("1. m/s").getUnit()
>>> a
<PhysicalUnit m/s>
>>> a.setName('meterpersecond')
>>> a
<PhysicalUnit meterpersecond>