/// <summary>
/// function to calculate Soft Spheres forcefield
/// </summary>
/// <param name="ensemble"></param>
public override void CalculateForceField(ParticleEnsemble ensemble)
{
// variable declarations
int i;
double posXi, posYi, radius;
double PotentialEnergy = 0.0;
// variable initializations
int BoxWidth = ensemble.BoxWidth;
int BoxHeight = ensemble.BoxHeight;
// #pragma omp parallel for
for (i = 0; i < ensemble.NumberOfParticles; ++i)
{
// initialize vectors holding forces
xforces[i] = 0.0; // HERE'S THE PROBLEM - THE INDEX WILL OVERRUN THE VECTOR SIZE!!!
yforces[i] = 0.0;
}
//#pragma omp parallel for
for (i = 0; i < ensemble.NumberOfParticles; ++i)
{
posXi = ensemble.GetXParticlePosition(i);
posYi = ensemble.GetYParticlePosition(i);
radius = ensemble.GetParticleRadius(i);
// get pixel vectors along the particle's X & Y axes for getting gradient of image field
// there are 2 steps to this process:
// (1) do some gaussian smoothing with a user defined width parameter (this determines how
// many pixels we need
// (2) determine the gradient from linear regression of the 3 surrounding points...
// cout << "particle " << i << " Xpos " << posXi << " Ypos " << posYi << endl;
// first get the vectors that we need - the length of the vectors depend on the width of the gaussian
// if the pixels are near the edge, the pixels beyond them (which arent in the image) are simply returned as zeros
// vector < double > AllThePixelsAlongX = pParticleSet->GetAllThePixelsAlongX(posYi,posXi,RangeEitherSide);
// xforces[i] = pParticleSet->GetGradientScaleFactor()*GaussianSmoothedSlope(posXi,AllThePixelsAlongX);
// cout << "Xposition " << posXi << endl;
if (m_CalculateForceField_TempArray.Length < RangeEitherSide + 1)
{
m_CalculateForceField_TempArray = new double[RangeEitherSide + 1];
}
int count;
//List<double> SubsetOfPixelsAlongX = GetSubsetOfPixelsAlongX(posYi, posXi, RangeEitherSide + 1);
GetSubsetOfPixelsAlongX(posXi, posYi, RangeEitherSide + 1, ref m_CalculateForceField_TempArray, out count);
// for(int kk=0; kk<SubsetOfPixelsAlongX.size(); ++kk){
// cout << kk << " " << SubsetOfPixelsAlongX[kk] << endl;
// }
// cout << "Xposition " << posXi << endl;
// for(int kk=1;kk<SubsetOfPixelsAlongX.size();++kk){cout << kk << " " << SubsetOfPixelsAlongX[kk] << endl;}
//xforces[i] = ensemble.GetGradientScaleFactor() * GaussianSmoothedSlope(posXi, SubsetOfPixelsAlongX);
xforces[i] = ensemble.GradientScaleFactor * GaussianSmoothedSlope(posXi, m_CalculateForceField_TempArray, count);
// vector < double > AllThePixelsAlongY = pParticleSet->GetAllThePixelsAlongY(posXi,posYi,RangeEitherSide);
// cout << "Yposition " << posYi << endl;
// for(int kk=0;kk<AllThePixelsAlongY.size();++kk){cout << kk << " " << AllThePixelsAlongY[kk] << endl;}
// yforces[i] = pParticleSet->GetGradientScaleFactor()*GaussianSmoothedSlope(posYi,AllThePixelsAlongY);
//List<double> SubsetOfPixelsAlongY = GetSubsetOfPixelsAlongY(posXi, posYi, RangeEitherSide + 1);
GetSubsetOfPixelsAlongY(posXi, posYi, RangeEitherSide + 1, ref m_CalculateForceField_TempArray, out count);
// cout << "Yposition " << endl;
//yforces[i] = ensemble.GetGradientScaleFactor() * GaussianSmoothedSlope(posYi, SubsetOfPixelsAlongY);
yforces[i] = ensemble.GradientScaleFactor * GaussianSmoothedSlope(posYi, m_CalculateForceField_TempArray, count);
// cout << "yforces[i] " << i << " " << yforces[i] << endl;
// get the gradient scale factor, depending on whether the particle is attractive or repulsive
AtomicInfo typeInfo = ParticleStaticObjects.AtomPropertiesDefinition.Lookup[(ensemble.Particles[i]).TypeID];
double attractiveOrRepulsiveFactor = typeInfo.AttractiveOrRepulsive;
xforces[i] *= attractiveOrRepulsiveFactor;
yforces[i] *= attractiveOrRepulsiveFactor;
}
ensemble.AddXForces(xforces); // set the forces in the Particle Ensemble Object
ensemble.AddYForces(yforces); // set the potential energy
ensemble.AddPotentialEnergy(PotentialEnergy); // add in the potential energy
}
public override void CalculateForceField(ParticleEnsemble ensemble)
{
// variable declarations
double posXi, posYi;
double posXj, posYj;
double LJxf, LJyf;
double ijSeparation = 0.0, LJforce = 0.0, PotentialEnergy = 0.0;
int j, kk, ctr, dimensions = 2;
// variable initializations
int BoxWidth = ensemble.BoxWidth;
int BoxHeight = ensemble.BoxHeight;
double MaxForce = ensemble.MaxForceThreshold;
double MinForce = -1.0 * (ensemble.MaxForceThreshold);
// initialize vectors holding forces
for (int i = 0; i < ensemble.NumberOfParticles; ++i)
{
LJxforces[i]=0.0;
LJyforces[i]=0.0;
}
ensemble.ResetAllParticlesNotWithinRange();
for (int i = 0; i < ensemble.NumberOfParticles; ++i)
{
Particle particlei = ensemble.GetParticle(i);
for (j = (i + 1); j < ensemble.NumberOfParticles; ++j)
{
Particle particlej = ensemble.GetParticle(j);
if (particlei.GridSector.IsInJoiningSectors(particlej.GridSector) == false)
{
continue;
}
// get the interparticle separation distances
ijSeparation = ensemble.GetInterParticleSeparation(i, j);
// update the radial distribution function
// pParticleSet->UpdateRadialDistributionFunction((int)(ijSeparation));
double cutoffDistance = particlei.ParticleType.MinimumDistance[particlej.TypeID]; // MinimumDistance[i, j];
//double cutoffDistance = MinimumDistance[i, j];
if (ijSeparation < cutoffDistance)
{
// SQRT MOD
ijSeparation = Math.Sqrt(ijSeparation);
double LJgradientTermA = particlei.ParticleType.LJgradientTermA[particlej.TypeID];
double LJgradientTermB = particlei.ParticleType.LJgradientTermB[particlej.TypeID];
// for each particle, change the appropriate element of the setWithinRangeOfAnotherParticle vector to true
posXi = ensemble.GetXParticlePosition(i);
posYi = ensemble.GetYParticlePosition(i);
posXj = ensemble.GetXParticlePosition(j);
posYj = ensemble.GetYParticlePosition(j);
// PotentialEnergy += LJenergyTermA[i][j]/(pow(ijSeparation,12.0))+LJenergyTermB[i][j]/pow(ijSeparation,6.0)+epsilon;
//LJforce = (posXj - posXi) * (LJgradientTermA[i, j] / Math.Pow(ijSeparation, 13.0) + LJgradientTermB[i, j] / Math.Pow(ijSeparation, 7.0)) / ijSeparation;
LJforce = (posXj - posXi) * (LJgradientTermA / Math.Pow(ijSeparation, 13.0) + LJgradientTermB / Math.Pow(ijSeparation, 7.0)) / ijSeparation;
if (Math.Abs(LJforce) > MaxForce || Math.Abs(LJforce) < MinForce) { LJforce = 0.0; } // error check for real-time stability...
else if (double.IsNaN(LJforce) || double.IsInfinity(LJforce)) { LJforce = 0.0; } // error check for real-time stability...
LJxforces[i] += LJforce;
LJxforces[j] += -1.0 * LJforce;
// cout << "x "<< i << " " << j << " " << LJforce << endl;
// cout << "i " << i << " LJxforces[i] " << LJxforces[i] << " j " << j << " LJxforces[j] " << LJxforces[j] << endl;
// cout << "xi:=" << posXi << ";" << "xj:=" << posXj << ";" << "yi:=" << posYi << ";" << "yj:=" << posYj << ";" << LJxforces[i] << endl;
//LJforce = (posYj - posYi) * (LJgradientTermA[i, j] / Math.Pow(ijSeparation, 13.0) + LJgradientTermB[i, j] / Math.Pow(ijSeparation, 7.0)) / ijSeparation;
LJforce = (posYj - posYi) * (LJgradientTermA / Math.Pow(ijSeparation, 13.0) + LJgradientTermB / Math.Pow(ijSeparation, 7.0)) / ijSeparation;
if (Math.Abs(LJforce) > MaxForce || Math.Abs(LJforce) < MinForce) { LJforce = 0.0; } // error check for real-time stability...
else if (double.IsNaN(LJforce) || double.IsInfinity(LJforce)) { LJforce = 0.0; } // error check for real-time stability...
LJyforces[i] += LJforce;
LJyforces[j] += -1.0 * LJforce;
ensemble.SetParticlesWithinRange(i, j);
ensemble.SetParticlesWithinRange(j, i);
}
}
}
// set the forces in the Particle Ensemble Object
ensemble.AddXForces(LJxforces);
ensemble.AddYForces(LJyforces);
// set the potential energy
ensemble.AddPotentialEnergy(PotentialEnergy);
}