/// <summary>
/// Returns instance of InterpolativeMathFunction with automatically generated derivations.
/// </summary>
/// <param name="expression">Interpreted math function of two real variables i.e. "x^2 + y^2".</param>
/// <returns>
/// Instance of class if mathExpression is in correct format, othervise
/// returns null;
/// </returns>
public static InterpolativeMathFunction FromExpression(MathExpression expression)
{
// TODO: osetrit vynimky pre neplatne vstupy
var f = expression.Interpret();
var dx = expression.InterpretMathDifferentiation
(expression.Variables[0]);
var dy = expression.InterpretMathDifferentiation
(expression.Variables[1]);
var dxy = expression.InterpretMathDifferentiation
(expression.Variables[0], expression.Variables[1]);
return new InterpolativeMathFunction(f, dx, dy, dxy);
}