protected override void initCalculations()
{
LayoutSystem.ComputeParams param = new LayoutSystem.ComputeParams();
float useless = 0;
param.StepLength = stepLength;
HostSystem.CalcDescentVector(HostSystem.CurrentStateBuffer, param); // calc desc vector and energies
HostSystem.CalcTotalEnergyAndDotProduct(HostSystem.CurrentStateBuffer, HostSystem.CurrentStateBuffer,
HostSystem.EnergyBuffer, param, out energy, out useless, out checkSum);
}
/// <summary>
/// This function performs the first iteration of calculations
/// </summary>
protected override void initCalculations()
{
LayoutSystem.ComputeParams param = new LayoutSystem.ComputeParams();
param.StepLength = stepLength;
HostSystem.CalcDescentVector(HostSystem.CurrentStateBuffer, param); // calc desc vector and energies
HostSystem.CalcTotalEnergyAndDotProduct(HostSystem.CurrentStateBuffer, HostSystem.CurrentStateBuffer,
HostSystem.EnergyBuffer, param, out energy, out pGradE, out checkSum);
initialEnergy = energy;
deltaEnergyBound = energy;
// energyEstim = estimEnergy();
}
protected override void update(int userCommand)
{
var graphSys = HostSystem.Environment.GetService <GraphSystem>();
LayoutSystem.ComputeParams param = new LayoutSystem.ComputeParams();
param.StepLength = stepLength;
float nextEnergy = 0;
float useless = 0;
if (HostSystem.CurrentStateBuffer != null)
{
if (HostSystem.RunPause == LayoutSystem.State.RUN)
{
for (int i = 0; i < graphSys.Config.IterationsPerFrame; ++i)
{
HostSystem.MoveVertices(
HostSystem.CurrentStateBuffer,
HostSystem.NextStateBuffer,
param
);
HostSystem.CalcDescentVector(
HostSystem.NextStateBuffer,
param
);
HostSystem.CalcTotalEnergyAndDotProduct(
HostSystem.NextStateBuffer,
HostSystem.NextStateBuffer,
HostSystem.EnergyBuffer,
param,
out nextEnergy,
out useless,
out checkSum
);
HostSystem.SwapBuffers();
if (nextEnergy < energy)
{
++progress;
}
else
{
progress = 0;
stepLength = decreaseStep(stepLength);
}
if (progress > maxProgress)
{
progress = 0;
stepLength = increaseStep(stepLength);
}
deltaEnergy = nextEnergy - energy;
energy = nextEnergy;
++numIterations;
}
}
}
var debStr = HostSystem.Environment.GetService <DebugStrings>();
debStr.Add(Color.Black, "WOLFRAM MODE");
debStr.Add(Color.Aqua, "Step factor = " + stepLength);
debStr.Add(Color.Aqua, "Energy = " + energy);
debStr.Add(Color.Aqua, "deltaEnergy = " + deltaEnergy);
debStr.Add(Color.Aqua, "Iteration = " + numIterations);
}
/// <summary>
/// This is the main function to call at each iteration
/// </summary>
/// <param name="userCommand"></param>
protected override void update(int userCommand)
{
var graphSys = HostSystem.Environment.GetService <GraphSystem>();
LayoutSystem.ComputeParams param = new LayoutSystem.ComputeParams();
bool cond1 = false;
bool cond2 = false;
float energyThreshold = (float)HostSystem.ParticleCount / 10000.0f;
// float energyThreshold = (float)HostSystem.ParticleCount / 5000000.0f;
float chosenStepLength = stepLength;
// Wolfe constants:
// float C1 = 0.1f;
// float C2 = 0.99f;
//float C1 = 0.3f;
//float C2 = 0.99f;
var graphSystem = HostSystem.Environment.GetService <GraphSystem>();
float C1 = graphSystem.Config.C1;
float C2 = graphSystem.Config.C2;
// Algorithm outline:
//
// 1. Calc descent vector pk
// 2. calc pk * grad(Ek)
// 3. calc Ek
// 4. try move with some step factor
// 5. calc pk * grad(Ek+1)
// 6. calc Ek+1
// 7. check Wolfe conditions
// 8. if both are OK GOTO 11
// 9. modify step factor
// 10. GOTO 4
// 11. swap try buffer with current buffer
// 12. GOTO 1
//
// manual step change:
if (userCommand > 0)
{
stepLength += 0.01f;
}
if (userCommand < 0)
{
stepLength -= 0.01f;
}
if (HostSystem.CurrentStateBuffer != null)
{
if (HostSystem.RunPause == LayoutSystem.State.RUN)
{
// StreamWriter sw = File.AppendText( "stepsize.csv" );
for (int i = 0; i < graphSys.Config.IterationsPerFrame; ++i)
{
float Ek = energy; // current energy
float Ek1 = 0; // next energy
float pkGradEk = 1; // current dot prodct
float pkGradEk1 = 1; // next dot prodct
cond1 = false;
cond2 = false;
int tries = 0;
param.StepLength = stepLength;
if (!FixedStep)
{
HostSystem.CalcTotalEnergyAndDotProduct(
HostSystem.CurrentStateBuffer,
HostSystem.CurrentStateBuffer,
HostSystem.EnergyBuffer,
param, out Ek, out pkGradEk, out checkSum);
}
while (!(cond1 && cond2))
{
if (FixedStep)
{
cond1 = true;
cond2 = true;
}
param.StepLength = stepLength;
HostSystem.MoveVertices(
HostSystem.CurrentStateBuffer,
HostSystem.NextStateBuffer,
param); // move vertices in descent direction
HostSystem.CalcDescentVector(
HostSystem.NextStateBuffer,
param); // calculate energies and next descent vectors
if (!FixedStep)
{
HostSystem.CalcTotalEnergyAndDotProduct(
HostSystem.CurrentStateBuffer,
HostSystem.NextStateBuffer,
HostSystem.EnergyBuffer,
param, out Ek1, out pkGradEk1, out checkSum);
// check Wolfe conditions:
cond1 = (Ek1 - Ek <= stepLength * C1 * pkGradEk);
cond2 = (pkGradEk1 >= C2 * pkGradEk);
//// if we are very close to minimum, do not check conditions (it leads to infinite cycles)
//if (Math.Abs(Ek1 - Ek) < energyThreshold)
//{
// cond1 = cond2 = true;
//}
//// Debug output:
//if (tries > 4)
//{
// Console.WriteLine("step = " + stepLength + " " +
// "cond#1 = " + (cond1 ? "TRUE" : "FALSE") + " " +
// "cond#2 = " + (cond2 ? "TRUE" : "FALSE") + " " +
// "deltaE = " + (Ek1 - Ek)
// );
//}
// change step length:
if (cond1 && !cond2)
{
stepLength = increaseStep(stepLength);
}
if (!cond1 && !cond2)
{
stepLength = increaseStep(stepLength);
}
if (!cond1 && cond2)
{
stepLength = decreaseStep(stepLength);
}
}
++tries;
++numIterations;
// To prevent freeze:
if (tries >= graphSys.Config.SearchIterations)
{
break;
}
}
// swap buffers: --------------------------------------------------------------------
HostSystem.SwapBuffers();
if (stepLength == chosenStepLength) // if the new step length is the same as before
{
++stepStability;
}
else
{
stepStability = 0;
}
chosenStepLength = stepLength;
energy = Ek1;
deltaEnergy = Ek1 - Ek;
// update bound deltaE:
if (Math.Abs(deltaEnergy) < Math.Abs(deltaEnergyBound))
{
deltaEnergyBound = deltaEnergy;
}
pGradE = pkGradEk1;
// write to file:
// sw.WriteLine(numIterations + "," + stepLength + "," + (float)Math.Sqrt(Math.Abs(deltaEnergyBound) / initialEnergy)
// + "," + getChangeRate());
if (!FixedStep &&
stepStability >= graphSys.Config.SwitchToManualAfter) // if stable step length found, switch to fixed step
{
FixedStep = true;
// Console.WriteLine("Step fixed at iteration #" + numIterations);
}
//if (Math.Abs(deltaEnergy) < energyThreshold) // if deltaE is low enough, switch to fixed step
//{
// FixedStep = true;
// HostSystem.RunPause = LayoutSystem.State.PAUSE;
// Console.WriteLine( energyThreshold + " " + deltaEnergy );
//
//}
}
// sw.Close();
}
}
var debStr = HostSystem.Environment.GetService <DebugStrings>();
debStr.Add(Color.Black, "AUTO MODE");
// debStr.Add(Color.Black, "C1 = " + C1);
// debStr.Add(Color.Black, "C2 = " + C2);
debStr.Add(Color.Aqua, "Step factor = " + chosenStepLength);
// debStr.Add(Color.Aqua, "Energy = " + energy);
debStr.Add(Color.Aqua, "DeltaE = " + deltaEnergy);
// debStr.Add(Color.Aqua, "pTp = " + pGradE);
debStr.Add(Color.Aqua, "Iteration = " + numIterations);
debStr.Add(Color.RoyalBlue, "Mode: " + (FixedStep ? "FIXED" : "SEARCH"));
debStr.Add(Color.Aqua, "Stability = " + stepStability);
// debStr.Add(Color.Aqua, "E/E0 = " + (energy/initialEnergy));
debStr.Add(Color.Aqua, "Change = " + getChangeRate());
// debStr.Add(Color.Orchid, "Check sum = " + checkSum);
// debStr.Add(Color.Black, "E0/N = " + (initialEnergy / (float)HostSystem.ParticleCount));
// debStr.Add(Color.Black, "nodes/edges = " + ((float)HostSystem.ParticleCount / (float)HostSystem.LinkCount ));
// debStr.Add(Color.Black, "ESTIM = " + energyEstim);
// debStr.Add(Color.Black, "REAL/ESTIM = " + (initialEnergy / energyEstim));
}