# SimPEG.maps.IdentityMap#

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

Bases: object

Identity mapping and the base mapping class for all other SimPEG mappings.

The IdentityMap class is used to define the mapping when the model parameters are the same as the parameters used in the forward simulation. For a discrete set of model parameters $$\mathbf{m}$$, the mapping $$\mathbf{u}(\mathbf{m})$$ is equivalent to applying the identity matrix; i.e.:

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

The IdentityMap also acts as the base class for all other SimPEG mapping classes.

Using the mesh or nP input arguments, the dimensions of the corresponding mapping operator can be permanently set; i.e. (mesh.nC, mesh.nC) or (nP, nP). However if both input arguments mesh and nP are None, the shape of mapping operator is arbitrary and can act on any vector; i.e. has shape (*, *).

Parameters:
meshdiscretize.BaseMesh

The number of parameters accepted by the mapping is set to equal the number of mesh cells.

nPint, or ‘*’

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 the mapping with respect to the input parameters. dot(map1) Multiply two mappings to create a SimPEG.maps.ComboMap. The transform inverse is not implemented. test([m, num]) Derivative test for the mapping.

## Galleries and Tutorials using SimPEG.maps.IdentityMap#

Maps: Parametric Block in a Layer

Maps: Parametric Block in a Layer

Maps: ComboMaps

Maps: ComboMaps

Maps: Parametrized Layer

Maps: Parametrized Layer

Maps: Mesh2Mesh

Maps: Mesh2Mesh

Maps: ComboMaps

Maps: ComboMaps

PF: Gravity: Tiled Inversion Linear

PF: Gravity: Tiled Inversion Linear

Magnetic inversion on a TreeMesh

Magnetic inversion on a TreeMesh

Magnetic inversion on a TreeMesh

Magnetic inversion on a TreeMesh

Magnetic Amplitude inversion on a TreeMesh

Magnetic Amplitude inversion on a TreeMesh

3D DC inversion of Dipole Dipole array

3D DC inversion of Dipole Dipole array

Parametric DC inversion with Dipole Dipole array

Parametric DC inversion with Dipole Dipole array

2D inversion of Loop-Loop EM Data

2D inversion of Loop-Loop EM Data

Time-domain CSEM for a resistive cube in a deep marine setting

Time-domain CSEM for a resistive cube in a deep marine setting

EM: TDEM: Permeable Target, Inductive Source

EM: TDEM: Permeable Target, Inductive Source

EM: TDEM: 1D: Inversion

EM: TDEM: 1D: Inversion

EM: TDEM: 1D: Inversion with VTEM waveform

EM: TDEM: 1D: Inversion with VTEM waveform

Predict Response from a Conductive and Magnetically Viscous Earth

Predict Response from a Conductive and Magnetically Viscous Earth

Method of Equivalent Sources for Removing VRM Responses

Method of Equivalent Sources for Removing VRM Responses

FLOW: Richards: 1D: Forward Simulation

FLOW: Richards: 1D: Forward Simulation

FLOW: Richards: 1D: Inversion

FLOW: Richards: 1D: Inversion

Petrophysically guided inversion (PGI): Linear example

Petrophysically guided inversion (PGI): Linear example

Petrophysically guided inversion: Joint linear example with nonlinear relationships

Petrophysically guided inversion: Joint linear example with nonlinear relationships

Heagy et al., 2017 1D RESOLVE and SkyTEM Bookpurnong Inversions

Heagy et al., 2017 1D RESOLVE and SkyTEM Bookpurnong Inversions

Heagy et al., 2017 1D RESOLVE Bookpurnong Inversion

Heagy et al., 2017 1D RESOLVE Bookpurnong Inversion

Effective Medium Theory Mapping

Effective Medium Theory Mapping

Heagy et al., 2017 Casing Example

Heagy et al., 2017 Casing Example

Heagy et al., 2017 1D FDEM and TDEM inversions

Heagy et al., 2017 1D FDEM and TDEM inversions

PF: Gravity: Laguna del Maule Bouguer Gravity

PF: Gravity: Laguna del Maule Bouguer Gravity

FLOW: Richards: 1D: Celia1990

FLOW: Richards: 1D: Celia1990

EM: Schenkel and Morrison Casing Model

EM: Schenkel and Morrison Casing Model

Straight Ray with Volume Data Misfit Term

Straight Ray with Volume Data Misfit Term

1D Forward Simulation for a Single Sounding

1D Forward Simulation for a Single Sounding

1D Forward Simulation for a Susceptible and Chargeable Earth

1D Forward Simulation for a Susceptible and Chargeable Earth

3D Forward Simulation on a Cylindrical Mesh

3D Forward Simulation on a Cylindrical Mesh

3D Forward Simulation on a Tree Mesh

3D Forward Simulation on a Tree Mesh

1D Inversion of for a Single Sounding

1D Inversion of for a Single Sounding

1D Forward Simulation for a Single Sounding

1D Forward Simulation for a Single Sounding

1D Forward Simulation with Chargeable and/or Magnetic Viscosity

1D Forward Simulation with Chargeable and/or Magnetic Viscosity

1D Forward Simulation with User-Defined Waveforms

1D Forward Simulation with User-Defined Waveforms

3D Forward Simulation for Transient Response on a Cylindrical Mesh

3D Forward Simulation for Transient Response on a Cylindrical Mesh

3D Forward Simulation with User-Defined Waveforms

3D Forward Simulation with User-Defined Waveforms

1D Inversion of Time-Domain Data for a Single Sounding

1D Inversion of Time-Domain Data for a Single Sounding

Linear Least-Squares Inversion

Linear Least-Squares Inversion

Sparse Inversion with Iteratively Re-Weighted Least-Squares

Sparse Inversion with Iteratively Re-Weighted Least-Squares

Forward Simulation of Total Magnetic Intensity Data

Forward Simulation of Total Magnetic Intensity Data

Forward Simulation of Gradiometry Data for Magnetic Vector Models

Forward Simulation of Gradiometry Data for Magnetic Vector Models

Sparse Norm Inversion for Total Magnetic Intensity Data on a Tensor Mesh

Sparse Norm Inversion for Total Magnetic Intensity Data on a Tensor Mesh

Forward Simulation of Gravity Anomaly Data on a Tensor Mesh

Forward Simulation of Gravity Anomaly Data on a Tensor Mesh

Forward Simulation of Gradiometry Data on a Tree Mesh

Forward Simulation of Gradiometry Data on a Tree Mesh

Least-Squares Inversion of Gravity Anomaly Data

Least-Squares Inversion of Gravity Anomaly Data

Sparse Norm Inversion of Gravity Anomaly Data

Sparse Norm Inversion of Gravity Anomaly Data

Forward Simulation of VRM Response on a Tree Mesh

Forward Simulation of VRM Response on a Tree Mesh

Forward Simulation Including Inductive Response

Forward Simulation Including Inductive Response

2.5D Forward Simulation of a DCIP Line

2.5D Forward Simulation of a DCIP Line

DC/IP Forward Simulation in 3D

DC/IP Forward Simulation in 3D

2.5D DC Resistivity and IP Least-Squares Inversion

2.5D DC Resistivity and IP Least-Squares Inversion

3D Least-Squares Inversion of DC and IP Data

3D Least-Squares Inversion of DC and IP Data

Simulate a 1D Sounding over a Layered Earth

Simulate a 1D Sounding over a Layered Earth

DC Resistivity Forward Simulation in 2.5D

DC Resistivity Forward Simulation in 2.5D

DC Resistivity Forward Simulation in 3D

DC Resistivity Forward Simulation in 3D

Least-Squares 1D Inversion of Sounding Data

Least-Squares 1D Inversion of Sounding Data

Sparse 1D Inversion of Sounding Data

Sparse 1D Inversion of Sounding Data

Parametric 1D Inversion of Sounding Data

Parametric 1D Inversion of Sounding Data

2.5D DC Resistivity Least-Squares Inversion

2.5D DC Resistivity Least-Squares Inversion

2.5D DC Resistivity Inversion with Sparse Norms

2.5D DC Resistivity Inversion with Sparse Norms

3D Least-Squares Inversion of DC Resistivity Data

3D Least-Squares Inversion of DC Resistivity Data

Tensor Meshes

Tensor Meshes

Cylindrical Meshes

Cylindrical Meshes

Tree Meshes

Tree Meshes

Joint PGI of Gravity + Magnetic on an Octree mesh using full petrophysical information

Joint PGI of Gravity + Magnetic on an Octree mesh using full petrophysical information

Joint PGI of Gravity + Magnetic on an Octree mesh without petrophysical information

Joint PGI of Gravity + Magnetic on an Octree mesh without petrophysical information

Forward Simulation for Straight Ray Tomography in 2D

Forward Simulation for Straight Ray Tomography in 2D

Sparse Norm Inversion of 2D Seismic Tomography Data

Sparse Norm Inversion of 2D Seismic Tomography Data

Cross-gradient Joint Inversion of Gravity and Magnetic Anomaly Data

Cross-gradient Joint Inversion of Gravity and Magnetic Anomaly Data