SimPEG.maps.ExpMap#

class SimPEG.maps.ExpMap(mesh=None, nP=None, **kwargs)[source]#

Bases: IdentityMap

Mapping that computes the natural exponentials of the model parameters.

Where \(\mathbf{m}\) is a set of model parameters, ExpMap creates a mapping \(\mathbf{u}(\mathbf{m})\) that computes the natural exponential of every element in \(\mathbf{m}\); i.e.:

\[\mathbf{u}(\mathbf{m}) = exp(\mathbf{m})\]

ExpMap is commonly used when working with physical properties whose values span many orders of magnitude (e.g. the electrical conductivity \(\sigma\)). By using ExpMap, we can invert for a model that represents the natural log of a set of physical property values, i.e. when \(m = log(\sigma)\)

Parameters:

meshdiscretize.BaseMesh: The number of parameters accepted by the mapping is set to equal the number of mesh cells.
nPint: Set the number of parameters accepted by the mapping directly. Used if the number of parameters is known. Used generally when the number of parameters is not equal to the number of cells in a mesh.

Attributes

`is_linear`	Determine whether or not this mapping is a linear operation.
`mesh`	The mesh used for the mapping
`nP`	Number of parameters the mapping acts on.
`shape`	Dimensions of the mapping operator

Methods

`deriv`(m[, v])	Derivative of mapping with respect to the input parameters.
`dot`(map1)	Multiply two mappings to create a `SimPEG.maps.ComboMap`.
`inverse`(D)	Apply the inverse of the exponential mapping to an array.
`test`([m, num])	Derivative test for the mapping.