# SimPEG.maps.Weighting.inverse#

Weighting.inverse(D)[source]#

Apply the inverse of the weighting mapping to an array.

For the weighting mapping $$\mathbf{u}(\mathbf{m})$$, the inverse mapping on a variable $$\mathbf{x}$$ is performed by multplying each element by the reciprocal of its corresponding weighting value, i.e.:

$\mathbf{m} = \mathbf{u}^{-1}(\mathbf{x}) = \mathbf{w}^{-1} \odot \mathbf{x}$

where $$\odot$$ is the Hadamard product. The inverse mapping may also be defined using a linear operator as follows:

$\mathbf{m} = \mathbf{u}^{-1}(\mathbf{x}) = \mathbf{P^{-1} m} \;\;\;\;\; \textrm{where} \;\;\;\;\; \mathbf{P} = diag(\mathbf{w})$
Parameters
Dnumpy.ndarray

A set of input values

Returns
numpy.ndarray

A numpy.ndarray containing result of applying the inverse mapping to the elements in D; which in this case is simply dividing each element by its corresponding weight.