# SimPEG.maps.LogMap.deriv#

LogMap.deriv(m, v=None)[source]#

Derivative of mapping with respect to the input parameters.

For a mapping $$\mathbf{u}(\mathbf{m})$$ that computes the natural logarithm for each parameter in the model $$\mathbf{m}$$, i.e.:

$\mathbf{u}(\mathbf{m}) = log(\mathbf{m})$

the derivative of the mapping with respect to the model is a diagonal matrix of the form:

$\frac{\partial \mathbf{u}}{\partial \mathbf{m}} = \textrm{diag} \big ( \mathbf{m}^{-1} \big )$
Parameters
m

A vector representing a set of model parameters

v

If not None, the method returns the derivative times the vector v

Returns
scipy.sparse.csr_matrix

Derivative of the mapping with respect to the model parameters. If the input argument v is not None, the method returns the derivative times the vector v.