/// <summary>
/// Check if the two polynomial terms have the same type of variables (eg: 2xy vs 5yx)
/// </summary>
private static bool CompareVariables(PolynomialNode <double> term1, PolynomialNode <double> term2)
{
if (term2.Variables.Count == term1.Variables.Count)
{
bool varsMatch = true;
foreach (var kvp in term2.Variables)
{
varsMatch = varsMatch && term1.Variables.ContainsKey(kvp.Key) && term1.Variables[kvp.Key] == kvp.Value;
}
return(varsMatch);
}
else
{
return(false);
}
}
public static string BuildPolynomialTerm(PolynomialNode <double> node)
{
var variables = node.Variables.Select(kvp => kvp.Key + ((kvp.Value == 1) ? "" : "^" + kvp.Value)).ToArray();
var arr = string.Join("", variables);
var sign = node.Coefficient >= 0 ? 1 : -1;
var coefficient = Math.Abs(node.Coefficient) == 1 ? "" : Math.Abs(node.Coefficient).ToString();
var term = "";
if (sign > 0)
{
term = $"+{coefficient}{arr}";
}
else
{
term = $"-{coefficient}{arr}";
}
return(term);
}
/// <summary>
/// Creates list of PolynomialNode (expression) and adds it to stack.
/// </summary>
/// <param name="polynomialTerm"></param>
/// <param name="expressionStack"></param>
private void AddToExpressionStack(string polynomialTerm, Stack <List <PolynomialNode <double> > > expressionStack)
{
var polyNode = new PolynomialNode <double>()
{
};
polyNode.Coefficient = GetCoefficient(polynomialTerm);
// case: AX^mY^n
var i = 0;
while (i < polynomialTerm.Length)
{
var c = polynomialTerm[i];
if (char.IsLetter(c))
{
// case: x^k
if ((i + 1) < polynomialTerm.Length && polynomialTerm[i + 1] == '^' && (i + 2) < polynomialTerm.Length && char.IsDigit(polynomialTerm[i + 2]))
{
var exponent = int.Parse(polynomialTerm[i + 2].ToString());
polyNode.Variables.Add(c, exponent);
i += 3;
continue;
}
else
{
// case: x
polyNode.Variables.Add(c, 1);
i++;
continue;
}
}
i++;
}
var list = new List <PolynomialNode <double> >();
list.Add(polyNode);
expressionStack.Push(list);
}
