/// <summary>
/// Finds all terms of a polynomial
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="terms"></param>
/// <param name="subtree"></param>
/// <returns></returns>
internal static Dictionary <T, Entity> GatherMonomialInformation <T>(List <Entity> terms, Entity subtree)
{
var monomialsByPower = new Dictionary <T, Entity>();
// here we fill the dictionary with information about monomials' coefficiants
foreach (var child in terms)
{
// TODO
Entity free;
object pow;
if (typeof(T) == typeof(decimal))
{
pow = new TreeAnalyzer.PrimitiveDouble();
}
else
{
pow = new TreeAnalyzer.PrimitiveInt();
}
TreeAnalyzer.IPrimitive <T> q = pow as TreeAnalyzer.IPrimitive <T>;
ParseMonomial <T>(subtree, child, out free, ref q);
if (free == null)
{
return(null);
}
if (!monomialsByPower.ContainsKey(q.GetValue()))
{
monomialsByPower[q.GetValue()] = 0;
}
monomialsByPower[q.GetValue()] += free;
}
// TODO: do we need to simplify all values of monomialsByPower?
return(monomialsByPower);
}
internal static void ParseMonomial <T>(Entity aVar, Entity expr, out Entity freeMono, ref TreeAnalyzer.IPrimitive <T> power)
{
if (expr.FindSubtree(aVar) == null)
{
freeMono = expr;
return;
}
freeMono = 1; // a * b
bool allowFloat = typeof(T) == typeof(decimal);
foreach (var mp in TreeAnalyzer.LinearChildren(expr, "mulf", "divf", Const.FuncIfMul))
{
if (mp.FindSubtree(aVar) == null)
{
freeMono *= mp;
}
else if (mp.entType == Entity.EntType.OPERATOR &&
mp.Name == "powf")
{
var pow_num = MathS.CanBeEvaluated(mp.Children[1]) ? mp.Children[1].Eval() : mp.Children[1];
// x ^ a is bad
if (pow_num.entType != Entity.EntType.NUMBER)
{
freeMono = null;
return;
}
// x ^ 0.3 is bad
if (!allowFloat && !pow_num.Eval().IsInteger())
{
freeMono = null;
return;
}
if (mp == aVar)
{
if (allowFloat)
{
(power as TreeAnalyzer.PrimitiveDouble).Add(pow_num.GetValue().Real);
}
else
{
(power as TreeAnalyzer.PrimitiveInt).Add(pow_num.GetValue().Real.AsInt());
}
}
else
{
if (!MathS.CanBeEvaluated(mp.Children[1]))
{
freeMono = null;
return;
}
Entity tmpFree;
// TODO
object pow;
if (typeof(T) == typeof(decimal))
{
pow = new TreeAnalyzer.PrimitiveDouble();
}
else
{
pow = new TreeAnalyzer.PrimitiveInt();
}
TreeAnalyzer.IPrimitive <T> q = pow as TreeAnalyzer.IPrimitive <T>;
ParseMonomial <T>(aVar, mp.Children[0], out tmpFree, ref q);
if (tmpFree == null)
{
freeMono = null;
return;
}
else
{
// Can we eval it right here?
mp.Children[1] = mp.Children[1].Eval();
freeMono *= MathS.Pow(tmpFree, mp.Children[1]);
power.AddMp(q.GetValue(), mp.Children[1].GetValue());
}
}
}
else if (mp == aVar)
{
if (allowFloat)
{
(power as TreeAnalyzer.PrimitiveDouble).Add(1);
}
else
{
(power as TreeAnalyzer.PrimitiveInt).Add(1);
}
}
else
{
// a ^ x, (a + x) etc. are bad
if (mp.FindSubtree(aVar) != null)
{
freeMono = null;
return;
}
freeMono *= mp;
}
}
// TODO: do we need to simplify freeMono?
}
