/// <summary>
/// Adds a function that needs to be.
/// </summary>
/// <param name="unknown">The unknown with a minimum value.</param>
/// <param name="strict">The strict minimum value for the unknown.</param>
public void AddMinimum(Unknown unknown, double strict)
{
if (unknown == null)
{
return;
}
_minimum.Add(unknown, strict);
}
/// <summary>
/// Build a new solver from scratch using the current constraints and variables.
/// </summary>
/// <returns>The solver.</returns>
private void BuildSolver()
{
_solver = new SparseRealSolver();
_map.Clear();
// Build our total function
bool hasResolved = true;
var diffs = new Dictionary <Unknown, Function>();
while (hasResolved)
{
hasResolved = false;
_lambdas.Clear();
var f = Minimize ?? 1.0;
int index = 1;
foreach (var c in _constraints.Keys)
{
if (c.IsFixed)
{
if (!c.Value.IsZero())
{
Warn(this, new WarningEventArgs($"Could not {_constraints[c]}."));
}
continue;
}
var lambda = new Unknown($"lambda{index++}", UnknownTypes.Scalar);
f += lambda * c;
_lambdas.Add(lambda);
}
// Differentiate the Lagrangian function
if (LogInfo)
{
Console.WriteLine(f);
}
diffs.Clear();
f.Differentiate(null, diffs);
// Handle unknowns that need to be minimized
foreach (var m in _minimum)
{
if (m.Key.IsFixed)
{
if (m.Key.Value < m.Value)
{
Warn(this, new WarningEventArgs($"Minimum was violated for {m.Key}."));
}
continue;
}
if (diffs.TryGetValue(m.Key, out var eq))
{
diffs[m.Key] = eq - 0.01 / (m.Key - m.Value);
}
}
// First try to precompute as many constraints as possible
var done = new HashSet <Unknown>();
do
{
done.Clear();
foreach (var pair in diffs)
{
var c = pair.Value;
// Skip the ones we already resolved
if (c.Resolve(0.0))
{
hasResolved = true;
if (LogInfo)
{
Console.WriteLine($"Resolved {c}");
}
// This has been fixed!
done.Add(pair.Key);
}
else if (c.IsFixed && !c.Value.IsZero())
{
if (_constraints.TryGetValue(c, out var description))
{
Warn(this, new WarningEventArgs($"Could not {description}."));
}
else
{
Warn(this, new WarningEventArgs($"Could not {c}."));
}
// This has been fixed!
done.Add(pair.Key);
}
}
foreach (var key in done)
{
diffs.Remove(key);
}
}while (done.Count > 0);
}
// Setup the equations and solution
_solution = new DenseVector <double>(_equations.Count);
_oldSolution = new DenseVector <double>(_equations.Count);
foreach (var eq in diffs)
{
var index = _map.Map(eq.Key);
var rowEquation = eq.Value.CreateEquation(index, _map, _solver);
_equations.Add(eq.Key, rowEquation);
switch (eq.Key.Type)
{
case UnknownTypes.Scale:
if (eq.Key.Value.IsZero())
{
_solution[index] = 1.0;
}
else
{
_solution[index] = eq.Key.Value;
}
break;
case UnknownTypes.Length:
if (eq.Key.Value < 0)
{
_solution[index] = 0;
}
else
{
_solution[index] = eq.Key.Value;
}
break;
case UnknownTypes.X:
case UnknownTypes.Y:
_solution[index] = Fix;
break;
default:
_solution[index] = eq.Key.Value;
break;
}
_oldSolution[index] = _solution[index];
if (LogInfo)
{
Console.WriteLine($"df/d{eq.Key} = {eq.Value}");
}
}
foreach (var m in _minimum)
{
var initial = m.Key.Value;
if (m.Key.Value <= m.Value)
{
initial = m.Value + 1e-9;
}
if (_map.TryGet(m.Key, out var index))
{
_solution[index] = initial;
_oldSolution[index] = _solution[index];
}
}
}
public ConstantRowEquation(Unknown uk, ISparseSolver <double> solver, int row)
{
_uk = uk;
_rhs = solver.GetElement(row);
}
/// <summary>
/// Initializes a new instance of the <see cref="UnknownFunction"/> class.
/// </summary>
/// <param name="unknown">The unknown.</param>
public UnknownFunction(Unknown unknown)
{
_unknown = unknown ?? throw new ArgumentNullException(nameof(unknown));
}
public RowEquation(Unknown uk, ISparseSolver <double> solver, int row, int column)
{
_uk = uk;
_elt = null;
_elt = solver.GetElement(new MatrixLocation(row, column));
}
