# get_or_create_dimension function

(Shortest import: `from brian2 import get_or_create_dimension)`

brian2.units.fundamentalunits.get_or_create_dimension(*args, **kwds)

  Create a new Dimension object or get a reference to an existing one. This function takes care of only creating new objects if they were not created before and otherwise returning a reference to an existing object. This allows to compare dimensions very efficiently using `is`.

  Parameters:

    args : sequence of `float`

    > A sequence with the indices of the 7 elements of an SI dimension.

    kwds : keyword arguments

    > a sequence of `keyword=value` pairs where the keywords are the names of the SI dimensions, or the standard unit.

  Notes

  The 7 units are (in order):

  Length, Mass, Time, Electric Current, Temperature, Quantity of Substance, Luminosity

  and can be referred to either by these names or their SI unit names, e.g. length, metre, and m all refer to the same thing here.

  Examples

  The following are all definitions of the dimensions of force

      >>> from brian2 import *
      >>> get_or_create_dimension(length=1, mass=1, time=-2)
      metre * kilogram * second ** -2
      >>> get_or_create_dimension(m=1, kg=1, s=-2)
      metre * kilogram * second ** -2
      >>> get_or_create_dimension([1, 1, -2, 0, 0, 0, 0])
      metre * kilogram * second ** -2