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operator: alternative material averaging method 

If constant cell material is activated, material probing is performed
only in the center of a primary cell.

This should improve and simplify SAR calculation if all materials
are assumed as constant within a primary YEE cell.

Usage from Matlab/Octave:
FDTD = InitFDTD('CellConstantMaterial',1);

Signed-off-by: Thorsten Liebig <Thorsten.Liebig@gmx.de>
pull/1/head
Thorsten Liebig 2013-02-18 10:38:55 +01:00
parent e9495ef749
commit 8d5043bd44
4 changed files with 27 additions and 10 deletions
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21
FDTD/operator.cpp
View File

@ -95,6 +95,7 @@ void Operator::Init()
m_Exc = 0;
m_TimeStepFactor = 1;
m_MatCellShiftFaktor = 0.25;
}
void Operator::Delete()
@ -1220,8 +1221,8 @@ bool Operator::Calc_EffMatPos(int ny, const unsigned int* pos, double* EffMat) c
//******************************* epsilon,kappa averaging *****************************//
//shift up-right
shiftCoord[n] = coord[n]+delta*0.5;
shiftCoord[nP] = coord[nP]+deltaP*0.25;
shiftCoord[nPP] = coord[nPP]+deltaPP*0.25;
shiftCoord[nP] = coord[nP]+deltaP*m_MatCellShiftFaktor;
shiftCoord[nPP] = coord[nPP]+deltaPP*m_MatCellShiftFaktor;
A_n = GetNodeArea(ny,loc_pos,true);
EffMat[0] = GetMaterial(n, shiftCoord, 0)*A_n;
EffMat[1] = GetMaterial(n, shiftCoord, 1)*A_n;
@ -1229,8 +1230,8 @@ bool Operator::Calc_EffMatPos(int ny, const unsigned int* pos, double* EffMat) c
//shift up-left
shiftCoord[n] = coord[n]+delta*0.5;
shiftCoord[nP] = coord[nP]-deltaP_M*0.25;
shiftCoord[nPP] = coord[nPP]+deltaPP*0.25;
shiftCoord[nP] = coord[nP]-deltaP_M*m_MatCellShiftFaktor;
shiftCoord[nPP] = coord[nPP]+deltaPP*m_MatCellShiftFaktor;
--loc_pos[nP];
A_n = GetNodeArea(ny,loc_pos,true);
@ -1240,8 +1241,8 @@ bool Operator::Calc_EffMatPos(int ny, const unsigned int* pos, double* EffMat) c
//shift down-right
shiftCoord[n] = coord[n]+delta*0.5;
shiftCoord[nP] = coord[nP]+deltaP*0.25;
shiftCoord[nPP] = coord[nPP]-deltaPP_M*0.25;
shiftCoord[nP] = coord[nP]+deltaP*m_MatCellShiftFaktor;
shiftCoord[nPP] = coord[nPP]-deltaPP_M*m_MatCellShiftFaktor;
++loc_pos[nP];
--loc_pos[nPP];
A_n = GetNodeArea(ny,loc_pos,true);
@ -1251,8 +1252,8 @@ bool Operator::Calc_EffMatPos(int ny, const unsigned int* pos, double* EffMat) c
//shift down-left
shiftCoord[n] = coord[n]+delta*0.5;
shiftCoord[nP] = coord[nP]-deltaP_M*0.25;
shiftCoord[nPP] = coord[nPP]-deltaPP_M*0.25;
shiftCoord[nP] = coord[nP]-deltaP_M*m_MatCellShiftFaktor;
shiftCoord[nPP] = coord[nPP]-deltaPP_M*m_MatCellShiftFaktor;
--loc_pos[nP];
A_n = GetNodeArea(ny,loc_pos,true);
EffMat[0] += GetMaterial(n, shiftCoord, 0)*A_n;
@ -1269,7 +1270,7 @@ bool Operator::Calc_EffMatPos(int ny, const unsigned int* pos, double* EffMat) c
double length=0;
//shift down
shiftCoord[n] = coord[n]-delta_M*0.25;
shiftCoord[n] = coord[n]-delta_M*m_MatCellShiftFaktor;
shiftCoord[nP] = coord[nP]+deltaP*0.5;
shiftCoord[nPP] = coord[nPP]+deltaPP*0.5;
--loc_pos[n];
@ -1283,7 +1284,7 @@ bool Operator::Calc_EffMatPos(int ny, const unsigned int* pos, double* EffMat) c
length=delta_ny;
//shift up
shiftCoord[n] = coord[n]+delta*0.25;
shiftCoord[n] = coord[n]+delta*m_MatCellShiftFaktor;
shiftCoord[nP] = coord[nP]+deltaP*0.5;
shiftCoord[nPP] = coord[nPP]+deltaPP*0.5;
++loc_pos[n];

5
FDTD/operator.h
View File

@ -81,6 +81,9 @@ public:
virtual void SetTimestepFactor(double factor);
bool GetTimestepValid() const {return !m_InvaildTimestep;}
//! Set operator to assume a constant material inside a cell (material probing in the cell center)
void SetCellConstantMaterial() {m_MatCellShiftFaktor=0.5;}
virtual double GetNumberCells() const;
virtual unsigned int GetNumberOfNyquistTimesteps() const {return m_Exc->GetNyquistNum();}
@ -204,6 +207,8 @@ protected:
//! Get the material at a given coordinate, direction and type from CSX (internal use only)
virtual double GetMaterial(int ny, const double coords[3], int MatType, bool markAsUsed=true) const;
double m_MatCellShiftFaktor;
//! Calculate the effective/averaged material properties at the given position and direction ny.
virtual bool Calc_EffMatPos(int ny, const unsigned int* pos, double* EffMat) const;

2
matlab/InitFDTD.m
View File

@ -12,6 +12,8 @@ function FDTD = InitFDTD(varargin)
% CoordSystem: choose coordinate system (0 Cartesian, 1 Cylindrical)
% TimeStep: force to use a given timestep (dangerous!)
% TimeStepFactor: reduce the timestep by a given factor (>0 to <=1)
% CellConstantMaterial: set to 1 to assume a material is constant inside
% a cell (material probing in cell center)
%
% examples:
% %default init with 1e9 max. timesteps and -50dB end-criteria

9
openems.cpp
View File

@ -647,6 +647,15 @@ int openEMS::SetupFDTD(const char* file)
if (SetupOperator(FDTD_Opts)==false)
return 2;
int cellConstantMaterial=0;
FDTD_Opts->QueryIntAttribute("CellConstantMaterial",&cellConstantMaterial);
if (cellConstantMaterial==1)
{
FDTD_Op->SetCellConstantMaterial();
if (g_settings.GetVerboseLevel()>0)
cerr << "Enabling constant cell material assumption." << endl;
}
m_Exc = new Excitation();
FDTD_Op->SetExcitationSignal(m_Exc);
FDTD_Op->AddExtension(new Operator_Ext_Excitation(FDTD_Op));