MaplePrimes - answers and comments on Question, which function equivalent to reduce q modulo p?

This is q mod(p)

Kitonum — Mon, 06 Feb 2012 23:18:29 Z

The example:

15 mod(4);

how about polynomial case i know the algorithm,

marram — Tue, 07 Feb 2012 05:59:14 Z

how about polynomial case

i know the algorithm, but not sure the answer should be 0 or a polynomial

List<String> var = new List<String>();
            var.Add("x");
            var.Add("y");
            var.Add("z");
            string q = "3*x^3*y+2*x^2*y^2-3*x*y+5*x";
            List<String> p_list = new List<String>();
            p_list.Add("x^2*y+5*x^2+y^2");
            p_list.Add("7*x*y^2-2*y^3+1");
            string result2 = bt.Reduce(q, p_list, var);
     result2 may be 0 or -3*x*y+5*x-15*x^3-2.85714285714286*y^3+50*x^2+10*y^2+0.42857

public string Reduce(string p, List<string> Q, List<String> order)
        {
            string r = p;
            string q = "0";
            string f = "";
            Dictionary<String, double> Rrq = new Dictionary<String, double>();
            Dictionary<String, double> temp = new Dictionary<String, double>();
            // only assume three variables
            Dictionary<String,double> order0 = new Dictionary<String, double>();
            Dictionary<String,double> order1 = new Dictionary<String,double>();
            Dictionary<String,double> order2 = new Dictionary<String,double>();
            foreach (String s in Q)
            {
                int counter = 0;
                while(max_deg_var(s)!=order[counter])
                {
                    counter += 1;
                }
                if (counter == 0)
                    order0.Add(s, max_deg(s));
                if (counter == 1)
                    order1.Add(s, max_deg(s));
                if (counter == 2)
                    order2.Add(s, max_deg(s));
            }
            foreach (KeyValuePair<String, double> s in order0.OrderByDescending(k => k.Value))
                Rrq.Add(s.Key, s.Value);
            foreach (KeyValuePair<String, double> s in order1.OrderByDescending(k => k.Value))
                Rrq.Add(s.Key, s.Value);
            foreach (KeyValuePair<String, double> s in order2.OrderByDescending(k => k.Value))
                Rrq.Add(s.Key, s.Value);

            string Mr = "";

            while (r != "0")
            {
                f = selectpoly(r, Rrq, order[0]);
                int counter = 0;
                while (!string.IsNullOrEmpty(f))
                {
                    if (counter == 3)
                        Console.WriteLine("");
                    r = Expand(r + "-(" + Expand(selectpoly_reducer_term(r, Rrq, order[0]) + "*(" + f + ")") + ")");
                    counter += 1;
                    //debug
                    //r = "-3*x*y+5*x-15*x^3-2.857142857*y^3+50*x^2+10*y^2+.428571428571429";
                    //     -3*x*y+5*x-15*x^3-2.85714285714286*y^3+50*x^2+10*y^2+0.42857
                    f = selectpoly(r, Rrq, order[0]);
                }
                Mr = Mr_Term(r, Rrq, order[0]);
                if (!string.IsNullOrEmpty(Mr))
                {
                    q = Expand(q + "+" + Mr);
                    r = Expand(r + "-(" + Mr + ")");
                }
                else
                {
                    return q;
                }
            }
            return q;
        }

List<String> var = new List<String>(

marram — Tue, 07 Feb 2012 06:01:57 Z