[Dick Moores] >>> Actually, I'm trying to write a Python script that computes all 3 >>> roots of a cubic equation. Do you happen to have one tucked >>> away in your store of wisdom and tricks? (One for real coefficients >>> will do).
[Tim Peters] >> I don't, no. You can code one for cubics from Cardano's formula, e.g., >> >> http://mathworld.wolfram.com/CubicFormula.html >> >> but it's rarely worth the bother -- it's complicated and doesn't >> generalize. [Dick] > I accept this challenge to write a complicated script of little value. Cool! If it's just for fun, it's fun. >> In practice, roots for polynomials beyond quadratics are >> usually obtained by numerical approximation methods that don't care >> much about the polynomial's degree. > Are these "numerical approximation methods" pythonically possible? Of course, but coding general-purpose root finders-- even if "general" is limited to just polynomials --requires mathematical and numeric expertise. If it interests you, there are book-length treatments of the subject, and there's really no easy reliable approach. Good online sources for numeric algorithms include: http://www.netlib.org/ Just Googling on polynomial roots Python will point you to http://www.scipy.org/ _______________________________________________ Tutor maillist - [EMAIL PROTECTED] http://mail.python.org/mailman/listinfo/tutor
