# Overview of Electromagnetics in SimPEG¶

## The API¶

### Problem¶

class SimPEG.EM.Base.BaseEMProblem(mesh, **kwargs)

Optional Properties:

Other Properties:

Me

Edge inner product matrix

MeI

Edge inner product matrix

MeMu

Edge inner product matrix for (mu). Used in the H-J formulation

MeMuDeriv(u, v=None, adjoint=False)

Derivative of MeMu with respect to the model.

MeMuI

Inverse of MeMu

MeMuIDeriv(u, v=None, adjoint=False)

Derivative of MeMuI with respect to the model

MeSigma

Edge inner product matrix for (sigma). Used in the E-B formulation

MeSigmaDeriv(u, v=None, adjoint=False)

Derivative of MeSigma with respect to the model times a vector (u)

MeSigmaI

Inverse of the edge inner product matrix for (sigma).

MeSigmaIDeriv(u, v=None, adjoint=False)

Derivative of MeSigmaI with respect to the model

Mf

Face inner product matrix

MfI

Face inner product matrix

MfMui

Face inner product matrix for (mu^{-1}). Used in the E-B formulation

MfMuiDeriv(u, v=None, adjoint=False)

Derivative of MfMui with respect to the model.

MfMuiI

Inverse of MfMui.

MfMuiIDeriv(u, v=None, adjoint=False)

Derivative of MfMui with respect to the model

MfRho

Face inner product matrix for (rho). Used in the H-J formulation

MfRhoDeriv(u, v=None, adjoint=False)

Derivative of MfRho with respect to the model.

MfRhoI

Inverse of MfRho

MfRhoIDeriv(u, v=None, adjoint=False)

Derivative of MfRhoI with respect to the model.

class Solver(A, **kwargs)

Bases: object

clean()
Vol
dataPair

alias of Data

deleteTheseOnModelUpdate

matrices to be deleted if the model maps for conductivity and/or permeability are updated

mapPair

alias of IdentityMap

mu

Magnetic Permeability (H/m)

mui

Inverse Magnetic Permeability (m/H)

rho

Electrical resistivity (Ohm m)

rhoDeriv

Derivative of Electrical resistivity (Ohm m) wrt the model.

rhoMap

Mapping of Electrical resistivity (Ohm m) to the inversion model.

sigma

Electrical conductivity (S/m)

sigmaDeriv

Derivative of Electrical conductivity (S/m) wrt the model.

sigmaMap

Mapping of Electrical conductivity (S/m) to the inversion model.

solverOpts = {}
storeInnerProduct = True
surveyPair

alias of BaseSurvey

verbose = False

### Survey¶

class SimPEG.EM.Base.BaseEMSurvey(srcList, **kwargs)
eval(f)

Parameters: u (Fields) – fields object numpy.ndarray data
evalDeriv(f)

### Sources¶

class SimPEG.EM.Base.BaseEMSrc(rxList, **kwargs)

Required Properties:

• integrate (Boolean): integrate the source term?, a boolean, Default: False
• loc (Array): location of the source, a list or numpy array of <class ‘float’>, <class ‘int’> with shape (*, 3) or (3)
eval(prob)
• $$s_m$$ : magnetic source term
• $$s_e$$ : electric source term
Parameters: prob (BaseFDEMProblem) – FDEM Problem tuple tuple with magnetic source term and electric source term
evalDeriv(prob, v=None, adjoint=False)

Derivatives of the source terms with respect to the inversion model - s_mDeriv : derivative of the magnetic source term - s_eDeriv : derivative of the electric source term

Parameters: prob (BaseFDEMProblem) – FDEM Problem v (numpy.ndarray) – vector to take product with adjoint (bool) – adjoint? tuple tuple with magnetic source term and electric source term derivatives times a vector
integrate

integrate (Boolean): integrate the source term?, a boolean, Default: False

loc

loc (Array): location of the source, a list or numpy array of <class ‘float’>, <class ‘int’> with shape (*, 3) or (3)

s_e(prob)

Electric source term

Parameters: prob (BaseFDEMProblem) – FDEM Problem numpy.ndarray electric source term on mesh
s_eDeriv(prob, v, adjoint=False)

Derivative of electric source term with respect to the inversion model

Parameters: prob (BaseFDEMProblem) – FDEM Problem v (numpy.ndarray) – vector to take product with adjoint (bool) – adjoint? numpy.ndarray product of electric source term derivative with a vector
s_m(prob)

Magnetic source term

Parameters: prob (BaseFDEMProblem) – FDEM Problem numpy.ndarray magnetic source term on mesh
s_mDeriv(prob, v, adjoint=False)

Derivative of magnetic source term with respect to the inversion model

Parameters: prob (BaseFDEMProblem) – FDEM Problem v (numpy.ndarray) – vector to take product with adjoint (bool) – adjoint? numpy.ndarray product of magnetic source term derivative with a vector