Core Package for E-MicroM solve E-MicroM problem whose geometry is mesh as a 3D regular grid not necessarly cubic which can be periodic in some dimensions. More...
Core Package for E-MicroM solve E-MicroM problem whose geometry is mesh as a 3D regular grid not necessarly cubic which can be periodic in some dimensions.
A E-MicromM problem consists in finding the value of magnetization at equilibrium of a system described in the EMM_LandauLifschitzSystem class:
find the field M such that 
where H is an excitation magnetic field.
This system is solved in the inherited classes from EMM_LandauLifschitzSystem see Relaxations Package for E-MicroM.
There are 2 kinds of solver :
- Relaxations Package for E-MicroM package is based on computing a relaxation by evaluating a time step which minimzes the energy. This packaes Relaxations Package for E-MicroM is linked with the Times Package for E-MicroM
- EMM_GaussLegendreRelaxation for general systems: the integral over time is computed with a Gauss-Legendre integration (see MATH_GaussLegendreIntegration)
- EMM_GradGaussLegendreRelaxation for systems whose gradient of each operator with respect to M can be computed
- EMM_TaylorExpansionRelaxation : the integral with respect of time is computed thanks to a taylor expansion of 2 order.
- ODE Package for E-MicroM package is based on integrating the system using an ODE integrator as Runge Kutta and whose time step is computed in order to controlate the estimated error on computing the magnetization field.
- EMM_LandauLifschitzRK45 for integrating the system using the Runge-Kutta Fehlman method
Each implementation for solving the Landau-Lifschitz system needs to compute new time step of the interface method EMM_Stepper::computeNewTimeStep()
The total magnetic excitation term H is the sum of the magnetic excitation fields (see Operators Package for E-MicroM ) composed by :
- the exchange magnetic excitation field described in EMM_ExchangeOperator class, (linear):
- with minimal storage EMMG_MinimalExchangeOperator
- with full storage of matrix EMMG_FullExchangeOperator
- the anisotropy magnetic excitation field described in EMM_AnisotropyOperator classes, (linear/non linear, gradH computationable):
- uniaxial anisotropy EMMG_UniaxialAnisotropyOperator
- planar anisotropy EMMG_PlanarAnisotropyOperator
- cubic anisotropy EMMG_CubicAnisotropyOperator
- mixed of the three above anisotropies EMMG_AnisotropyOperator
- mixed of uniaxial or planar anisotropy EMMG_LinearAnisotropyOperator
- the demagnetized field described in EMMG_DemagnetizedOperator class (linear) or in EMMG_PeriodicalDemagnetizedOperator class for periodic domain.
- the Zeeman magnetic excitation field described in EMM_ZeemanOperator class (constant)
- the magnetostriction magnetic excitation field described in EMM_MagnetostrictionOperator class (non linear; gradH not computationable)
The geometry of the domain is modelized by a regular 3D mesh parallelepiped : EMM_Grid3D
The matter(s) of the geometry is described in the general EMM_Matter class specialized with
- EMM_MagnetostrictiveMatter class for magnetostrictive matters which can be specialied with
- EMM_HyperElasticMatter class for elastic matters with 2 parameters
- EMM_CubicElasticMatter class for elastic matters with 3 parameters
- EMM_HyperElasticMatter class for elastic matters with 2 parameters
The distributions of the matters and the anisotropy directions (if different of matters) in the domain are described in EMM_AnisotropyDirectionsField class.
the Hysteresis Package for E-MicroM manages the simulation of hysteresis cycles.
The main class called the EMM_Run::run() method.
To see the options, call:
When options is provided, it is possible to
- compute an equilibrium state emicrom_main.exe {options} make run
- make primary/elementary/case tests emicrom_main.exe {options} make test
The classes list is as follow:
- EMM_Object is the base class for all the package.
- EMM_LandauLifschitzSystem is the main class to solve a e-microm system whose subclasses are
- EMM_GaussLegendreRelaxation where the Gauss Legendre approximation is used to compute the new magnetization at next time step
- EMM_GradGaussLegendreRelaxation where the Gauss Legendre approximation is used to compute the new magnetization at next time step and the gradient is used to compute the ne time step
- EMM_TaylorExpansionRelaxation where the taylor expansion is used to compute the new magnetization at next time step when all used operators are affine
A Landau lifshitz system contained operators:
- Exchange operator EMM_ExchangeOperator which is a EMM_LinearOperator implemented in the generic package EMMG_MinimalExchangeOperator and EMMG_FullExchangeOperator whose difference is on the storage of the exchange data.
- Zeeman operator described in EMM_ZeemanOperator which is a constant operator
- Anisotropy operators:
- an uniaxial anysotropy operator EMMG_UniaxialAnisotropyOperator which is a linear operator
- a planar anysotropy operator EMMG_PlanarAnisotropyOperator which is a linear operator
- a mixture of anisotropy linear operators: EMMG_LinearAnisotropyOperator
- a cubic anisotropy operator EMMG_CubicAnisotropyOperator which is a non-linear operator
- a mixture of all anisotropy operators EMMG_AnisotropyOperator which is a non-linear operator
- A demagnetized operator EMMG_DemagnetizedOperator whose data are represented in a toeplitz matrix because of the regularity of the mesh. Each leaf block of the toeplitz matrix is computed by the class EMM_ElementaryDemagnetizedMatrix.
The magnetization field M and the magnetic excitation H are real field EMM_Field implemented in generic package EMMG_RealField based on a compat array EMM_RealArray
The data of the problem is modelized by
- EMM_Grid3D which defines the grid3D mesh
- EMM_Matter and EMM_MatterField which define the physical properties and the distribution of the matters in the domain
- EMM_AnisotropyDirectionsField which defines the distibution of the anisotropy directions in the domain
The EMM_VTK class is used to generate result VTK files used in PARAVIEW software
EMM_ClassFactory is the main class which generate classes.
The runner classes are
The core package organization of this package is as follow:
