This is an extension for IPython 0.11+ that at the moment mainly enables easy input of physical quantities (i.e. numbers with units). The implementation is adapted from Konrad Hinsen's "Scientific.Physics.PhysicalQuantities" module.
If the "uncertainties" module (http://github.com/newville/uncertainties/) is installed, you can also enter values with standard errors wherever you can enter quantities, see the examples below.
You can have a look at a short notebook tutorial put together by Hans Fangohr at http://www.southampton.ac.uk/~fangohr/blog/physical-quantities-numerical-value-with-units-in-python.html.
Quick installation advice:
Place physics.py in any directory on PYTHONPATH, or add its directory to
sys.path in your IPython ipython_config.py file. Then you can load it
either in the config file or on the command line as described here:
http://ipython.org/ipython-doc/dev/config/extensions/index.html
Quick usage examples:
In: 1 m // cm # convert between units
Out: 100 cm # (syntax inspired by Mathematica)
In: (1 m)/(1 s) # sugar for inline quantity input
Out: 1 m/s # in arbitrary expressions
In: Quantity('1 m')/Quantity('1 s') # this is the desugared form
Out: 1 m/s
In: // furlong/fortnight # convert units in last result
Out: 6012.8848 furlong/fortnight
In: alpha = 90 deg # more sugar for assignment: no
# parentheses needed
In: sin(alpha) # angle units work with NumPy
Out: 1.0 # trigonometric functions
In: m = 80 +/- 5 kg # calculating with uncertainties
In: v = 130 +/- 10 m/s # (needs the "uncertainties" module)
In: 0.5 * m * v**2 // kJ
Out: 676 +/- 112.25445 kJ
In: %tbl sqrt(?x**2 + ?y**2) // cm # quickly tabulate a formula:
x = 1 m # provide some values
y = 2 m
Out: 223.6068 cm # and get the result
x = 3 m # ... this continues as long as you
y = 4 m # enter new values
Out: 500 cm
In: c0 # important physical constants
Out: 2.9979246e+08 m/s
In: setprec(4) # set the display precision
In: c0
Out: 2.998e+08 m/s
The predefined constants are:
pi
e
c0 -- vacuum speed of light
mu0 -- magnetic constant
eps0 -- electric constant
Grav -- Newton's constant
hpl -- Planck's constant
hbar -- Planck's constant / 2pi
e0 -- elementary charge
me -- electron mass
mp -- proton mass
mn -- neutron mass
NA -- Avogadro's number
kb -- Boltzmann constant
g0 -- Standard earth gravity
R -- Universal gas constant
alpha -- fine structure constant
Ry -- Rydberg constant
mu_n -- Magnetic moment of the neutron
gamma -- Gyromagnetic ratio of the neutron
h0 -- dimensionless Hubble parameter
Please let me know if anything is missing.