simpeg.maps.LinearMap.deriv#
- LinearMap.deriv(m, v=None)[source]#
Derivative of the mapping with respect to the input parameters.
- Parameters:
- m(
nP
)numpy.ndarray
A vector representing a set of model parameters
- v(
nP
)numpy.ndarray
If not
None
, the method returns the derivative times the vector v
- m(
- Returns:
scipy.sparse.csr_matrix
ornumpy.ndarray
Derivative of the mapping with respect to the model parameters. For an identity mapping, this is just a sparse identity matrix. If the input argument v is not
None
, the method returns the derivative times the vector v; which in this case is just v.
Notes
Let \(\mathbf{m}\) be a set of model parameters and let \(\mathbf{I}\) denote the identity map. Where the identity mapping acting on the model parameters can be expressed as:
\[\mathbf{u} = \mathbf{I m},\]the deriv method returns the derivative of \(\mathbf{u}\) with respect to the model parameters; i.e.:
\[\frac{\partial \mathbf{u}}{\partial \mathbf{m}} = \mathbf{I}\]For the Identity map deriv simply returns a sparse identity matrix.