public void Discretize(DAEProblem problem)
{
foreach (var dery in problem.DifferentialVariables)
{
var y = problem.Mapping[dery];
var yprev = new Variable("" + y.Name + "_[t-1]", y.InternalValue);
problem.Parameters.Add(yprev);
problem.Equations.Add(new Equation(Sym.Par(y - yprev) - problem.TimeStep * dery));
PreMap.Add(y, yprev);
}
}
void resetVariables(Vector y, Vector ym1, Vector ym2, DAEProblem problem)
{
for (int i = 0; i < problem.DifferentialVariables.Count; i++)
{
var yt = problem.Mapping[problem.DifferentialVariables[i]];
var yt_1 = PreMap[yt];
var yt_2 = PreMap[yt_1];
yt.SetValue(y[i]);
yt_1.SetValue(ym1[i]);
yt_2.SetValue(ym2[i]);
}
}
public void Discretize(DAEProblem problem)
{
foreach (var dery in problem.DifferentialVariables)
{
var y = problem.Mapping[dery];
var ynext = new Variable("" + y.Name + "_[t+1]", y.InternalValue);
problem.AlgebraicVariables.Add(ynext);
problem.AlgebraicVariables.Remove(y);
problem.Parameters.Add(y);
problem.Equations.Add(new Equation(Sym.Par(ynext - y) - problem.TimeStep * dery));
Map.Add(y, ynext);
}
}
void fillVector(Vector y, Vector ym1, Vector ym2, DAEProblem problem)
{
for (int i = 0; i < problem.DifferentialVariables.Count; i++)
{
var yt = problem.Mapping[problem.DifferentialVariables[i]];
var yt_1 = PreMap[yt];
var yt_2 = PreMap[yt_1];
y[i] = yt.InternalValue;
ym1[i] = yt_1.InternalValue;
ym2[i] = yt_2.InternalValue;
}
}
void TakeStep(DAEProblem problem, double dt)
{
problem.TimeStep.SetValue(dt);
problem.Time.AddDelta(dt);
problem.Step(Solver);
foreach (var dery in problem.DifferentialVariables)
{
var cury = problem.Mapping[dery];
var yt_1 = PreMap[cury];
var yt_2 = PreMap[yt_1];
yt_2.SetValue(yt_1.InternalValue);
yt_1.SetValue(cury.InternalValue);
}
}
public void Discretize(DAEProblem problem)
{
foreach (var dery in problem.DifferentialVariables)
{
var y = problem.Mapping[dery];
var yt_1 = new Variable("" + y.Name + "_[t-1]", y.InternalValue);
problem.Parameters.Add(yt_1);
var yt_2 = new Variable("" + y.Name + "_[t-2]", y.InternalValue);
problem.Parameters.Add(yt_2);
problem.Equations.Add(new Equation(Sym.Par(3 * y - 4 * yt_1 + yt_2) - 2 * problem.TimeStep * dery));
PreMap.Add(y, yt_1);
PreMap.Add(yt_1, yt_2);
}
}
public List <TimeStep> Integrate(DAEProblem problem, ILogger logger)
{
StepSizeMax = Math.Abs(EndTime - StartTime) / 50.0;
var results = new List <TimeStep>();
problem.Time.SetValue(StartTime);
problem.TimeStep.SetValue(StepSize);
if (UseDulmageMendelsohnSolver)
{
Solver = new DecompositionSolver(logger);
}
else
{
Solver = new BasicNewtonSolver(logger);
}
double rho = 0;
double eps = 0;
Vector y1h = new Vector(problem.AlgebraicVariables.Count);
Vector y2h = new Vector(problem.AlgebraicVariables.Count);
Vector y0 = new Vector(problem.AlgebraicVariables.Count);
Vector yt_1 = new Vector(problem.AlgebraicVariables.Count);
Vector yt_2 = new Vector(problem.AlgebraicVariables.Count);
Vector dummy = new Vector(problem.AlgebraicVariables.Count);
double lastProgress = 0;
double currentProgress = 0;
while (problem.Time.InternalValue <= EndTime)
{
var x = problem.AlgebraicVariables.Select(v => v.InternalValue).ToArray();
var y = problem.DifferentialVariables.Select(v => v.InternalValue).ToArray();
var t0 = problem.Time.InternalValue;
var currentStep = new TimeStep()
{
Time = t0,
AlgebraicStates = x,
DifferentialStates = y
};
results.Add(currentStep);
rho = 0;
fillVector(y0, yt_1, yt_2, problem);
var dt = 0.0;
int iter = 0;
while (rho < 1)
{
dt = 2 * StepSize;
resetVariables(y0, yt_1, yt_2, problem);
problem.Time.SetValue(t0);
TakeStep(problem, 2 * StepSize);
fillVector(y2h, dummy, dummy, problem);
resetVariables(y0, yt_1, yt_2, problem);
problem.Time.SetValue(t0);
TakeStep(problem, StepSize);
TakeStep(problem, StepSize);
fillVector(y1h, dummy, dummy, problem);
eps = (y1h - y2h).GetNorm() / 6.0;
rho = StepSize * eps / Tolerance;
StepSize = Math.Min(StepSize * Math.Pow(1.0 / rho, 1.0 / 3.0), 2 * StepSize);
if (problem.Time.InternalValue + 2 * StepSize > EndTime)
{
StepSize = (EndTime - problem.Time.InternalValue) / 2.0;
}
if (StepSize < MinStepSize)
{
StepSize = MinStepSize;
}
problem.Time.SetValue(t0);
if (iter > 10)
{
break;
}
iter++;
}
problem.Time.AddDelta(dt);
currentProgress = problem.Time.InternalValue / EndTime;
if (currentProgress - lastProgress > 0.01)
{
OnIteration?.Invoke(problem.Time.InternalValue / EndTime);
lastProgress = currentProgress;
}
}
return(results);
}
public List <TimeStep> Integrate(DAEProblem problem, ILogger logger)
{
var results = new List <TimeStep>();
TotalSteps = (int)((EndTime - StartTime) / StepSize);
problem.Time.SetValue(StartTime);
problem.TimeStep.SetValue(StepSize);
if (UseDulmageMendelsohnSolver)
{
Solver = new DecompositionSolver(logger);
}
else
{
Solver = new BasicNewtonSolver(logger);
}
var x = problem.AlgebraicVariables.Select(v => v.InternalValue).ToArray();
var y = problem.DifferentialVariables.Select(v => v.InternalValue).ToArray();
var currentStep = new TimeStep()
{
Time = StartTime,
AlgebraicStates = x,
DifferentialStates = y
};
results.Add(currentStep);
var reportingInveral = TotalSteps / 100;
for (int i = 0; i < TotalSteps; i++)
{
problem.Time.AddDelta(StepSize);
problem.Step(Solver);
foreach (var dery in problem.DifferentialVariables)
{
var cury = problem.Mapping[dery];
var yt_1 = PreMap[cury];
var yt_2 = PreMap[yt_1];
yt_2.SetValue(yt_1.InternalValue);
yt_1.SetValue(cury.InternalValue);
}
x = problem.AlgebraicVariables.Select(v => v.InternalValue).ToArray();
y = problem.DifferentialVariables.Select(v => v.InternalValue).ToArray();
currentStep = new TimeStep()
{
Time = problem.Time.InternalValue,
AlgebraicStates = x,
DifferentialStates = y
};
results.Add(currentStep);
logger.Log(currentStep.ToString());
if (i % reportingInveral == 0)
{
OnIteration?.Invoke(problem.Time.InternalValue / EndTime);
}
//System.Threading.Thread.Sleep(2);
}
return(results);
}
public List <TimeStep> Integrate(DAEProblem problem, ILogger logger)
{
var results = new List <TimeStep>();
int numSteps = (int)((EndTime - StartTime) / StepSize);
double time = StartTime;
problem.Time.SetValue(StartTime);
problem.TimeStep.SetValue(StepSize);
if (UseDulmageMendelsohnSolver)
{
Solver = new DecompositionSolver(logger);
}
else
{
Solver = new BasicNewtonSolver(logger);
}
var x = problem.AlgebraicVariables.Select(v => v.InternalValue).ToArray();
var y = problem.DifferentialVariables.Select(v => v.InternalValue).ToArray();
var currentStep = new TimeStep()
{
Time = time,
AlgebraicStates = x,
DifferentialStates = y
};
results.Add(currentStep);
for (int i = 0; i < numSteps; i++)
{
problem.Step(Solver);
foreach (var dery in problem.DifferentialVariables)
{
var cury = problem.Mapping[dery];
cury.AddDelta(dery.InternalValue);
}
time += StepSize;
problem.Time.AddDelta(StepSize);
x = problem.AlgebraicVariables.Select(v => v.InternalValue).ToArray();
y = problem.DifferentialVariables.Select(v => v.InternalValue).ToArray();
currentStep = new TimeStep()
{
Time = time,
AlgebraicStates = x,
DifferentialStates = y
};
results.Add(currentStep);
logger.Log(currentStep.ToString());
}
return(results);
}