/// <summary>
/// Execute using the secant method
/// </summary>
/// <param name="ckt">Circuit</param>
public override void Execute(Circuit ckt)
{
// Initialize
double xmin = Math.Min(Minimum, Maximum);
double xmax = Math.Max(Minimum, Maximum);
// Find out xmin and xmax
Apply(this, ckt, xmin);
double ymin = Measurement.Measure(ckt) - Target;
Apply(this, ckt, xmax);
double ymax = Measurement.Measure(ckt) - Target;
double width = xmax - xmin;
double tol = Math.Abs(xmax) * RelTol + AbsTol;
// Make sure the signs are opposite
if (ymin == 0.0)
{
Result = xmin;
return;
}
if (ymax == 0.0)
{
Result = xmax;
return;
}
if (ymin * ymax > 0.0)
{
throw new DesignException("Cannot find zero");
}
// Perform a bisection step until the width has reached half the tolerance
while (width > tol)
{
// Get the intersection with y=0
double m = (ymax - ymin) / (xmax - xmin);
double x = xmin - ymin / m;
Apply(this, ckt, x);
double y = Measurement.Measure(ckt) - Target;
tol = Math.Abs(x) * RelTol + AbsTol;
// Narrow down our search region depending on the sign
if (ymin * y >= 0.0)
{
xmin = x;
}
else
{
xmax = x;
}
width = xmax - xmin;
Result = x;
// Check iteration count
Iterations++;
if (Iterations > MaxIterations)
{
throw new DesignException("Maximum iteration count reached");
}
}
}
/// <summary>
/// Execute method of Newton
/// </summary>
/// <param name="ckt">Circuit</param>
public override void Execute(Circuit ckt)
{
// Initialize
double xmin = Math.Min(Minimum, Maximum);
double xmax = Math.Max(Minimum, Maximum);
Result = Start;
if (Result < xmin)
{
Result = xmin;
}
if (Result > xmax)
{
Result = xmax;
}
double error = double.PositiveInfinity;
double tol = 0.0;
Apply(this, ckt, Result);
double y = Measurement.Measure(ckt);
// Start iterations
while (Math.Abs(error) > tol)
{
// Numerical derivative calculation
double delta = RelDiff * Result + AbsDiff;
double m = 0.0;
if (Result - delta < xmin)
{
Apply(this, ckt, Result + delta);
m = (Measurement.Measure(ckt) - y) / delta;
}
else
{
Apply(this, ckt, Result - delta);
m = (y - Measurement.Measure(ckt)) / delta;
}
if (m == 0.0)
{
m = Math.Sign(error) * 1e-12;
}
// Calculate the new point
double nx = Result - (y - Target) / m;
if (nx < xmin)
{
nx = xmin;
}
if (nx > xmax)
{
nx = xmax;
}
Apply(this, ckt, nx);
y = Measurement.Measure(ckt);
error = (nx - Result) / Math.Abs(Math.Max(nx, Result));
Result = nx;
tol = Math.Max(Math.Abs(nx), Math.Abs(Target)) * RelTol + AbsTol;
// Track iteration count
Iterations++;
if (Iterations > MaxIterations)
{
throw new DesignException("Maximum iteration count reached");
}
}
}