New Scores Thursday October 14 & 17 2021 by James Pate Williams Jr

Diatonic F# Major Scale Random 480 Beats Per Minute 360 Measures 4 Beats Per Measure 4 Beat Value Cakewalk Sound Center Synthesizer Guitars Twelve String Guitar 3 Minutes Duration
Gypsy C Scale Random 360 Beats Per Minute 240 Measures 9 Beats Per Measure 8 Beat Value 3 Minutes SONAR Platinum rgcAudio z3ta+ Super Saw Synthesizer
Pentatonic C Major Scale Random 360 Beats Per Measure 240 Measures 9 Beats Per Measure 8 Beat Value 3 Minutes SONAR Platinum Lounge Lizard Bright Rhodes Chorus

Three Ways of Computing a Few Digits of Pi by James Pate Williams, Jr.

I wrote a short C++ program to calculate a few digits of pi, a famous transcendental number. The algorithms are as follows:

  1. Monte Carlo Method
  2. Leibniz’s Infinite Series
  3. Nilakantha’s Infinite Series

First the results then the C++ source code listing.

Steady State Temperature in an Insulated Cylinder by James Pate Williams, Jr.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Windows.Forms;

namespace SteadyStateTempCylinder
{
    public partial class MainForm : Form
    {
        private double steps;
        private int N, nsteps;
        private BackgroundWorker bw;
        private DateTime dt0;
        private List<PotPoint> pts;

        private double f(double r)
        {
            return r;
        }

        private double g(double r)
        {
            return r * r;
        }

        public MainForm()
        {
            InitializeComponent();
            comboBox1.SelectedIndex = 0;
            comboBox2.SelectedIndex = 0;
            comboBox3.SelectedIndex = 0;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (button1.Text.CompareTo("&Draw") == 0)
            {
                N = int.Parse((string)comboBox1.SelectedItem);
                nsteps = int.Parse((string)comboBox2.SelectedItem);
                steps = double.Parse((string)comboBox3.SelectedItem);
                bw = new BackgroundWorker();
                bw.DoWork += new DoWorkEventHandler(bw_DoWork);
                bw.ProgressChanged += new ProgressChangedEventHandler(bw_ProgressChanged);
                bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);
                bw.WorkerReportsProgress = true;
                bw.WorkerSupportsCancellation = true;
                bw.RunWorkerAsync();
                while (!bw.IsBusy) { }
                button1.Text = "&Stop";
                textBox1.Text = string.Empty;
            }

            else
                bw.CancelAsync();
        }

        private void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            if (e.ProgressPercentage >= 0 && e.ProgressPercentage <= 100)
                progressBar1.Value = e.ProgressPercentage;
        }

        private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            try
            {
                DateTime dt1 = DateTime.Now;
                TimeSpan ts = dt1 - dt0;
                DrawGraphForm dgf = new DrawGraphForm(1.0, 1.0, pts);
                dgf.Show();
                button1.Text = "&Draw";
                progressBar1.Value = 0;
                textBox1.Text = ts.Hours.ToString("D2") + ":";
                textBox1.Text += ts.Minutes.ToString("D2") + ":";
                textBox1.Text += ts.Seconds.ToString("D2") + ".";
                textBox1.Text += ts.Milliseconds.ToString("D3");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString(), "Warning Message",
                    MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
        }

        private void bw_DoWork(object sender, DoWorkEventArgs e)
        {
            dt0 = DateTime.Now;
            double step = 1.0 / Math.Sqrt(steps);
            double percent = steps / 100.0;
            int total = 0;
            int count = 0;
            pts = new List<PotPoint>();
            double r = 0.0, z = 0.0;
            double umin = double.MaxValue;
            double umax = double.MinValue;
            SteadyStateTemp sst = new SteadyStateTemp(1.0, 1.0, N, nsteps, f, g);

            while (r <= 1.0)
            {
                z = 0.0;

                while (z <= 1.0)
                {
                    double u = sst.u(r, z);
                    PotPoint pt = new PotPoint(r, z, u);

                    pts.Add(pt);
                    z += step;
                    count++;

                    if (count >= percent)
                    {
                        count = 0;
                        total++;
                        bw.ReportProgress(total);
                    }

                    if (u < umin)
                        umin = u;
                    if (u > umax)
                        umax = u;
                }

                r += step;
            }
        }
    }
}
using System;

namespace SteadyStateTempCylinder
{
    class SteadyStateTemp
    {
        private double A, B;
        private double[] Jn;
        private double[] lambda;
        private int N, n, nsteps;
        private BesselFunctions bf;
        private Func<double, double> f;
        Func<double, double> g;

        public SteadyStateTemp(
            double A,
            double B,
            int N, int nsteps,
            Func<double, double> f,
            Func<double, double> g)
        {
            double[] zeros = new double[N];
            this.A = A;
            this.B = B;
            this.N = N;
            this.nsteps = nsteps;
            this.f = f;
            this.g = g;
            Jn = new double[N + 1];
            lambda = new double[N + 1];
            bf = new BesselFunctions();
            bf.besszeros(1, N, zeros, 1);

            for (n = 1; n <= N; n++)
            {
                lambda[n] = zeros[n - 1];
                Jn[n] = J();
            }
        }

        private double SimpsonsRule(double lower, double upper, Func<double, double> f)
        {
            double h = (upper - lower) / nsteps;
            double h2 = 2.0 * h;
            double s = 0.0;
            double t = 0.0;
            double x = lower + h;

            for (int i = 1; i < nsteps; i += 2)
            {
                s += f(x);
                x += h2;
            }

            x = lower + h2;

            for (int i = 2; i < nsteps; i += 2)
            {
                t += f(x);
                x += h2;
            }

            return h * (f(lower) + 4 * s + 2 * t + f(upper)) / 3.0;
        }

        private double IIntegrand(double r)
        {
            return bf.bessj0(lambda[n] * r) * r;
        }

        private double I()
        {
            return SimpsonsRule(0.0, A, IIntegrand);
        }

        private double JIntegrand(double r)
        {
            double b0 = bf.bessj0(lambda[n] * r);

            return b0 * b0 * r;
        }

        private double J()
        {
            return SimpsonsRule(0.0, A, JIntegrand);
        }

        private double KIntegrand(double r)
        {
            return bf.bessj0(lambda[n] * r) * f(r) * r;
        }

        private double K()
        {
            return SimpsonsRule(0.0, A, KIntegrand);
        }

        private double LIntegrand(double r)
        {
            return bf.bessj0(lambda[n] * r) * g(r) * r;
        }

        private double L()
        {
            return SimpsonsRule(0.0, A, LIntegrand);
        }

        public double u(double r, double z)
        {
            double sum = 0.0;

            for (n = 1; n <= N; n++)
            {
                double denom = Math.Sinh(lambda[n] * B);
                double J0 = bf.bessj0(lambda[n] * r);
                double an = L() / Jn[n];
                double bn = K() / Jn[n];

                sum += J0 * an * Math.Sinh(lambda[n] * z) / denom;
                sum += J0 * bn * Math.Sinh(lambda[n] * (B - z)) / denom;
            }

            return sum;
        }
    }
}
using System;

namespace SteadyStateTempCylinder
{
    class BesselFunctions
    {
        public double bessj0(double x)
        {
            if (x == 0.0) return 1.0;
            if (Math.Abs(x) < 8.0)
            {
                int i;
                double z, z2, b0, b1, b2;
                double[] ar ={-0.75885e-15, 0.4125321e-13,
            -0.194383469e-11, 0.7848696314e-10, -0.267925353056e-8,
            0.7608163592419e-7, -0.176194690776215e-5,
            0.324603288210051e-4, -0.46062616620628e-3,
            0.48191800694676e-2, -0.34893769411409e-1,
            0.158067102332097, -0.37009499387265, 0.265178613203337,
            -0.872344235285222e-2};
                x /= 8.0;
                z = 2.0 * x * x - 1.0;
                z2 = z + z;
                b1 = b2 = 0.0;
                for (i = 0; i <= 14; i++)
                {
                    b0 = z2 * b1 - b2 + ar[i];
                    b2 = b1;
                    b1 = b0;
                }
                return z * b1 - b2 + 0.15772797147489;
            }
            else
            {
                double c, cosx, sinx, p0 = 0.0, q0 = 0.0;
                x = Math.Abs(x);
                c = 0.797884560802865 / Math.Sqrt(x);
                cosx = Math.Cos(x - 0.706858347057703e1);
                sinx = Math.Sin(x - 0.706858347057703e1);
                besspq0(x, ref p0, ref q0);
                return c * (p0 * cosx - q0 * sinx);
            }
        }

        public double bessj1(double x)
        {
            if (x == 0.0) return 1.0;
            if (Math.Abs(x) < 8.0)
            {
                int i;
                double z, z2, b0, b1, b2;
                double[] ar ={-0.19554e-15, 0.1138572e-13,
            -0.57774042e-12, 0.2528123664e-10, -0.94242129816e-9,
            0.2949707007278e-7, -0.76175878054003e-6,
            0.158870192399321e-4, -0.260444389348581e-3,
            0.324027018268386e-2, -0.291755248061542e-1,
            0.177709117239728e0, -0.661443934134543e0,
            0.128799409885768e1, -0.119180116054122e1};
                x /= 8.0;
                z = 2.0 * x * x - 1.0;
                z2 = z + z;
                b1 = b2 = 0.0;
                for (i = 0; i <= 14; i++)
                {
                    b0 = z2 * b1 - b2 + ar[i];
                    b2 = b1;
                    b1 = b0;
                }
                return x * (z * b1 - b2 + 0.648358770605265);
            }
            else
            {
                int sgnx;
                double c, cosx, sinx, p1 = 0.0, q1 = 0.0;
                sgnx = (x > 0.0) ? 1 : -1;
                x = Math.Abs(x);
                c = 0.797884560802865 / Math.Sqrt(x);
                cosx = Math.Cos(x - 0.706858347057703e1);
                sinx = Math.Sin(x - 0.706858347057703e1);
                besspq1(x, ref p1, ref q1);
                return sgnx * c * (p1 * sinx + q1 * cosx);
            }
        }

        private void besspq0(double x, ref double p0, ref double q0)
        {
            if (x < 8.0)
            {
                double b, cosx, sinx, j0x = 0.0, y0 = 0.0;
                b = Math.Sqrt(x) * 1.25331413731550;
                bessy01(x, ref y0, ref j0x);
                j0x = bessj0(x);
                x -= 0.785398163397448;
                cosx = Math.Cos(x);
                sinx = Math.Sin(x);
                p0 = b * (y0 * sinx + j0x * cosx);
                q0 = b * (y0 * cosx - j0x * sinx);
            }
            else
            {
                int i;
                double x2, b0, b1, b2, y;
                double[] ar1 ={-0.10012e-15, 0.67481e-15, -0.506903e-14,
            0.4326596e-13, -0.43045789e-12, 0.516826239e-11,
            -0.7864091377e-10, 0.163064646352e-8, -0.5170594537606e-7,
            0.30751847875195e-5, -0.536522046813212e-3};
                double[] ar2 ={-0.60999e-15, 0.425523e-14,
            -0.3336328e-13, 0.30061451e-12, -0.320674742e-11,
            0.4220121905e-10, -0.72719159369e-9, 0.1797245724797e-7,
            -0.74144984110606e-6, 0.683851994261165e-4};
                y = 8.0 / x;
                x = 2.0 * y * y - 1.0;
                x2 = x + x;
                b1 = b2 = 0.0;
                for (i = 0; i <= 10; i++)
                {
                    b0 = x2 * b1 - b2 + ar1[i];
                    b2 = b1;
                    b1 = b0;
                }
                p0 = x * b1 - b2 + 0.99946034934752;
                b1 = b2 = 0.0;
                for (i = 0; i <= 9; i++)
                {
                    b0 = x2 * b1 - b2 + ar2[i];
                    b2 = b1;
                    b1 = b0;
                }
                q0 = (x * b1 - b2 - 0.015555854605337) * y;
            }
        }

        private void besspq1(double x, ref double p1, ref double q1)
        {
            if (x < 8.0)
            {
                double b, cosx, sinx, j1x = 0.0, y1 = 0.0;
                b = Math.Sqrt(x) * 1.25331413731550;
                bessy01(x, ref j1x, ref y1);
                j1x = bessj1(x);
                x -= 0.785398163397448;
                cosx = Math.Cos(x);
                sinx = Math.Sin(x);
                p1 = b * (j1x * sinx - y1 * cosx);
                q1 = b * (j1x * cosx + y1 * sinx);
            }
            else
            {
                int i;
                double x2, b0, b1, b2, y;
                double[] ar1 ={0.10668e-15, -0.72212e-15, 0.545267e-14,
            -0.4684224e-13, 0.46991955e-12, -0.570486364e-11,
            0.881689866e-10, -0.187189074911e-8, 0.6177633960644e-7,
            -0.39872843004889e-5, 0.89898983308594e-3};
                double[] ar2 ={-0.10269e-15, 0.65083e-15, -0.456125e-14,
            0.3596777e-13, -0.32643157e-12, 0.351521879e-11,
            -0.4686363688e-10, 0.82291933277e-9, -0.2095978138408e-7,
            0.91386152579555e-6, -0.96277235491571e-4};
                y = 8.0 / x;
                x = 2.0 * y * y - 1.0;
                x2 = x + x;
                b1 = b2 = 0.0;
                for (i = 0; i <= 10; i++)
                {
                    b0 = x2 * b1 - b2 + ar1[i];
                    b2 = b1;
                    b1 = b0;
                }
                p1 = x * b1 - b2 + 1.0009030408600137;
                b1 = b2 = 0.0;
                for (i = 0; i <= 10; i++)
                {
                    b0 = x2 * b1 - b2 + ar2[i];
                    b2 = b1;
                    b1 = b0;
                }
                q1 = (x * b1 - b2 + 0.46777787069535e-1) * y;
            }
        }

        private void bessy01(double x, ref double y0, ref double y1)
        {
            if (x < 8.0)
            {
                int i;
                double z, z2, c, lnx, b0, b1, b2;
                double[] ar1 ={0.164349e-14, -0.8747341e-13,
            0.402633082e-11, -0.15837552542e-9, 0.524879478733e-8,
            -0.14407233274019e-6, 0.32065325376548e-5,
            -0.563207914105699e-4, 0.753113593257774e-3,
            -0.72879624795521e-2, 0.471966895957634e-1,
            -0.177302012781143, 0.261567346255047,
            0.179034314077182, -0.274474305529745};
                double[] ar2 ={0.42773e-15, -0.2440949e-13,
            0.121143321e-11, -0.5172121473e-10, 0.187547032473e-8,
            -0.5688440039919e-7, 0.141662436449235e-5,
            -0.283046401495148e-4, 0.440478629867099e-3,
            -0.51316411610611e-2, 0.423191803533369e-1,
            -0.226624991556755, 0.675615780772188,
            -0.767296362886646, -0.128697384381350};
                c = 0.636619772367581;
                lnx = c * Math.Log(x);
                c /= x;
                x /= 8.0;
                z = 2.0 * x * x - 1.0;
                z2 = z + z;
                b1 = b2 = 0.0;
                for (i = 0; i <= 14; i++)
                {
                    b0 = z2 * b1 - b2 + ar1[i];
                    b2 = b1;
                    b1 = b0;
                }
                y0 = lnx * bessj0(8.0 * x) + z * b1 - b2 - 0.33146113203285e-1;
                b1 = b2 = 0.0;
                for (i = 0; i <= 14; i++)
                {
                    b0 = z2 * b1 - b2 + ar2[i];
                    b2 = b1;
                    b1 = b0;
                }
                y1 = lnx * bessj1(8.0 * x) - c + x * (z * b1 - b2 + 0.2030410588593425e-1);
            }
            else
            {
                double c, cosx, sinx, p0 = 0.0, q0 = 0.0, p1 = 0.0, q1 = 0.0;
                c = 0.797884560802865 / Math.Sqrt(x);
                besspq0(x, ref p0, ref q0);
                besspq1(x, ref p1, ref q1);
                x -= 0.706858347057703e1;
                cosx = Math.Cos(x);
                sinx = Math.Sin(x);
                y0 = c * (p0 * sinx + q0 * cosx);
                y1 = c * (q1 * sinx - p1 * cosx);
            }
        }

        private double recipgamma(double x, ref double odd, ref double even)
        {
            int i;
            double alfa, beta, x2;
            double[] b = new double[13];

            b[1] = -0.283876542276024; b[2] = -0.076852840844786;
            b[3] = 0.001706305071096; b[4] = 0.001271927136655;
            b[5] = 0.000076309597586; b[6] = -0.000004971736704;
            b[7] = -0.000000865920800; b[8] = -0.000000033126120;
            b[9] = 0.000000001745136; b[10] = 0.000000000242310;
            b[11] = 0.000000000009161; b[12] = -0.000000000000170;
            x2 = x * x * 8.0;
            alfa = -0.000000000000001;
            beta = 0.0;
            for (i = 12; i >= 2; i -= 2)
            {
                beta = -(alfa * 2.0 + beta);
                alfa = -beta * x2 - alfa + b[i];
            }
            even = (beta / 2.0 + alfa) * x2 - alfa + 0.921870293650453;
            alfa = -0.000000000000034;
            beta = 0.0;
            for (i = 11; i >= 1; i -= 2)
            {
                beta = -(alfa * 2.0 + beta);
                alfa = -beta * x2 - alfa + b[i];
            }
            odd = (alfa + beta) * 2.0;
            return odd * x + even;
        }

        private void bessya01(double a, double x, ref double ya, ref double ya1)
        {
            if (a == 0.0)
            {
                bessy01(x, ref ya, ref ya1);
            }
            else
            {
                bool rec, rev;
                int n, na;
                double b, c, d, e, f, g, h = 0.0, p = 0.0, pi, q = 0.0, r, s;
                pi = Math.PI;
                na = (int)Math.Floor(a + 0.5);
                rec = (a >= 0.5);
                rev = (a < -0.5);
                if (rev || rec) a -= na;
                if (a == -0.5)
                {
                    p = Math.Sqrt(2.0 / pi / x);
                    f = p * Math.Sin(x);
                    g = -p * Math.Cos(x);
                }
                else if (x < 3.0)
                {
                    b = x / 2.0;
                    d = -Math.Log(b);
                    e = a * d;
                    c = (Math.Abs(a) < 1.0e-8) ? 1.0 / pi : a / Math.Sin(a * pi);
                    s = (Math.Abs(e) < 1.0e-8) ? 1.0 : Math.Sinh(e) / e;
                    e = Math.Exp(e);
                    g = recipgamma(a, ref p, ref q) * e;
                    e = (e + 1.0 / e) / 2.0;
                    f = 2.0 * c * (p * e + q * s * d);
                    e = a * a;
                    p = g * c;
                    q = 1.0 / g / pi;
                    c = a * pi / 2.0;
                    r = (Math.Abs(c) < 1.0e-8) ? 1.0 : Math.Sin(c) / c;
                    r *= pi * c * r;
                    c = 1.0;
                    d = -b * b;
                    ya = f + r * q;
                    ya1 = p;
                    n = 1;
                    do
                    {
                        f = (f * n + p + q) / (n * n - e);
                        c = c * d / n;
                        p /= (n - a);
                        q /= (n + a);
                        g = c * (f + r * q);
                        h = c * p - n * g;
                        ya += g;
                        ya1 += h;
                        n++;
                    } while (Math.Abs(g / (1.0 + Math.Abs(ya))) + Math.Abs(h / (1.0 + Math.Abs(ya1))) >
                                    1.0e-15);
                    f = -ya;
                    g = -ya1 / b;
                }
                else
                {
                    b = x - pi * (a + 0.5) / 2.0;
                    c = Math.Cos(b);
                    s = Math.Sin(b);
                    d = Math.Sqrt(2.0 / x / pi);
                    besspqa01(a, x, ref p, ref q, ref b, ref h);
                    f = d * (p * s + q * c);
                    g = d * (h * s - b * c);
                }
                if (rev)
                {
                    x = 2.0 / x;
                    na = -na - 1;
                    for (n = 0; n <= na; n++)
                    {
                        h = x * (a - n) * f - g;
                        g = f;
                        f = h;
                    }
                }
                else if (rec)
                {
                    x = 2.0 / x;
                    for (n = 1; n <= na; n++)
                    {
                        h = x * (a + n) * g - f;
                        f = g;
                        g = h;
                    }
                }
                ya = f;
                ya1 = g;
            }
        }

        private int start(double x, int n, int t)
        {
            int s;
            double p, q, r, y;

            s = 2 * t - 1;
            p = 36.0 / x - t;
            r = n / x;
            if (r > 1.0 || t == 1)
            {
                q = Math.Sqrt(r * r + s);
                r = r * Math.Log(q + r) - q;
            }
            else
                r = 0.0;
            q = 18.0 / x + r;
            r = (p > q) ? p : q;
            p = Math.Sqrt(2.0 * (t + r));
            p = x * ((1.0 + r) + p) / (1.0 + p);
            y = 0.0;
            q = y;
            do
            {
                y = p;
                p /= x;
                q = Math.Sqrt(p * p + s);
                p = x * (r + q) / Math.Log(p + q);
                q = y;
            } while (p > q || p < q - 1.0);
            return (t == 1) ? (int)Math.Floor(p + 1.0) : -(int)Math.Floor(-p / 2.0) * 2;
        }

        public void bessj(double x, int n, double[] j)
        {
            if (x == 0.0)
            {
                j[0] = 1.0;
                for (; n >= 1; n--) j[n] = 0.0;
            }
            else
            {
                int l, m, nu, signx;
                double x2, r, s;
                signx = (x > 0.0) ? 1 : -1;
                x = Math.Abs(x);
                r = s = 0.0;
                x2 = 2.0 / x;
                l = 0;
                nu = start(x, n, 0);
                for (m = nu; m >= 1; m--)
                {
                    r = 1.0 / (x2 * m - r);
                    l = 2 - l;
                    s = r * (l + s);
                    if (m <= n) j[m] = r;
                }
                j[0] = r = 1.0 / (1.0 + s);
                for (m = 1; m <= n; m++) r = j[m] *= r;
                if (signx < 0.0)
                    for (m = 1; m <= n; m += 2) j[m] = -j[m];
            }
        }

        private void spherbessj(double x, int n, double[] j)
        {
            if (x == 0.0)
            {
                j[0] = 1.0;
                for (; n >= 1; n--) j[n] = 0.0;
            }
            else if (n == 0)
            {
                double x2;
                if (Math.Abs(x) < 0.015)
                {
                    x2 = x * x / 6.0;
                    j[0] = 1.0 + x2 * (x2 * 0.3 - 1.0);
                }
                else
                    j[0] = Math.Sin(x) / x;
            }
            else
            {
                int m;
                double r, s;
                r = 0.0;
                m = start(x, n, 0);
                for (; m >= 1; m--)
                {
                    r = 1.0 / ((m + m + 1) / x - r);
                    if (m <= n) j[m] = r;
                }
                if (x < 0.015)
                {
                    s = x * x / 6.0;
                    j[0] = r = s * (s * 0.3 - 1.0) + 1.0;
                }
                else
                    j[0] = r = Math.Sin(x) / x;
                for (m = 1; m <= n; m++) r = j[m] *= r;
            }
        }

        private double loggamma(double x)
        {
            int i;
            double r, x2, y, f, u0, u1, u, z;
            double[] b = new double[19];

            if (x > 13.0)
            {
                r = 1.0;
                while (x <= 22.0)
                {
                    r /= x;
                    x += 1.0;
                }
                x2 = -1.0 / (x * x);
                r = Math.Log(r);
                return Math.Log(x) * (x - 0.5) - x + r + 0.918938533204672 +
                        (((0.595238095238095e-3 * x2 + 0.793650793650794e-3) * x2 +
                        0.277777777777778e-2) * x2 + 0.833333333333333e-1) / x;
            }
            else
            {
                f = 1.0;
                u0 = u1 = 0.0;
                b[1] = -0.0761141616704358; b[2] = 0.0084323249659328;
                b[3] = -0.0010794937263286; b[4] = 0.0001490074800369;
                b[5] = -0.0000215123998886; b[6] = 0.0000031979329861;
                b[7] = -0.0000004851693012; b[8] = 0.0000000747148782;
                b[9] = -0.0000000116382967; b[10] = 0.0000000018294004;
                b[11] = -0.0000000002896918; b[12] = 0.0000000000461570;
                b[13] = -0.0000000000073928; b[14] = 0.0000000000011894;
                b[15] = -0.0000000000001921; b[16] = 0.0000000000000311;
                b[17] = -0.0000000000000051; b[18] = 0.0000000000000008;
                if (x < 1.0)
                {
                    f = 1.0 / x;
                    x += 1.0;
                }
                else
                    while (x > 2.0)
                    {
                        x -= 1.0;
                        f *= x;
                    }
                f = Math.Log(f);
                y = x + x - 3.0;
                z = y + y;
                for (i = 18; i >= 1; i--)
                {
                    u = u0;
                    u0 = z * u0 + b[i] - u1;
                    u1 = u;
                }
                return (u0 * y + 0.491415393029387 - u1) * (x - 1.0) * (x - 2.0) + f;
            }
        }

        private double gamma(double x)
        {
            int inv;
            double y, s, f = 0.0, g, odd = 0.0, even = 0.0;

            if (x < 0.5)
            {
                y = x - Math.Floor(x / 2.0) * 2;
                s = Math.PI;
                if (y >= 1.0)
                {
                    s = -s;
                    y = 2.0 - y;
                }
                if (y >= 0.5) y = 1.0 - y;
                inv = 1;
                x = 1.0 - x;
                f = s / Math.Sin(3.14159265358979 * y);
            }
            else
                inv = 0;
            if (x > 22.0)
                g = Math.Exp(loggamma(x));
            else
            {
                s = 1.0;
                while (x > 1.5)
                {
                    x = x - 1.0;
                    s *= x;
                }
                g = s / recipgamma(1.0 - x, ref odd, ref even);
            }
            return (inv == 1 ? f / g : g);
        }

        private void bessjaplusn(double a, double x, int n, double[] ja)
        {
            if (x == 0.0)
            {
                ja[0] = (a == 0.0) ? 1.0 : 0.0;
                for (; n >= 1; n--) ja[n] = 0.0;
            }
            else if (a == 0.0)
            {
                bessj(x, n, ja);
            }
            else if (a == 0.5)
            {
                double s;
                s = Math.Sqrt(x) * 0.797884560802865;
                spherbessj(x, n, ja);
                for (; n >= 0; n--) ja[n] *= s;
            }
            else
            {
                int k, m, nu;
                double a2, x2, r, s, l, labda;
                l = 1.0;
                nu = start(x, n, 0);
                for (m = 1; m <= nu; m++) l = l * (m + a) / (m + 1);
                r = s = 0.0;
                x2 = 2.0 / x;
                k = -1;
                a2 = a + a;
                for (m = nu + nu; m >= 1; m--)
                {
                    r = 1.0 / (x2 * (a + m) - r);
                    if (k == 1)
                        labda = 0.0;
                    else
                    {
                        l = l * (m + 2) / (m + a2);
                        labda = l * (m + a);
                    }
                    s = r * (labda + s);
                    k = -k;
                    if (m <= n) ja[m] = r;
                }
                ja[0] = r = 1.0 / gamma(1.0 + a) / (1.0 + s) / Math.Pow(x2, a);
                for (m = 1; m <= n; m++) r = ja[m] *= r;
            }
        }

        private void besspqa01(double a, double x, ref double pa, ref double qa,
            ref double pa1, ref double qa1)
        {
            if (a == 0.0)
            {
                besspq0(x, ref pa, ref qa);
                besspq1(x, ref pa1, ref qa1);
            }
            else
            {
                bool rec, rev;
                int n, na = 0;
                double b, pi, p0, q0;
                pi = Math.PI;
                rev = a < -0.5;
                if (rev) a = -a - 1.0;
                rec = a >= 0.5;
                if (rec)
                {
                    na = (int)Math.Floor(a + 0.5);
                    a -= na;
                }
                if (a == -0.5)
                {
                    pa = pa1 = 1.0;
                    qa = qa1 = 0.0;
                }
                else if (x >= 3.0)
                {
                    double c, d, e, f, g, p, q, r, s, temp;
                    c = 0.25 - a * a;
                    b = x + x;
                    f = r = 1.0;
                    g = -x;
                    s = 0.0;
                    temp = x * Math.Cos(a * pi) / pi * 1.0e15;
                    e = temp * temp;
                    n = 2;
                    do
                    {
                        d = (n - 1 + c / n);
                        p = (2 * n * f + b * g - d * r) / (n + 1);
                        q = (2 * n * g - b * f - d * s) / (n + 1);
                        r = f;
                        f = p;
                        s = g;
                        g = q;
                        n++;
                    } while ((p * p + q * q) * n * n < e);
                    e = f * f + g * g;
                    p = (r * f + s * g) / e;
                    q = (s * f - r * g) / e;
                    f = p;
                    g = q;
                    n--;
                    while (n > 0)
                    {
                        r = (n + 1) * (2.0 - p) - 2.0;
                        s = b + (n + 1) * q;
                        d = (n - 1 + c / n) / (r * r + s * s);
                        p = d * r;
                        q = d * s;
                        e = f;
                        f = p * (e + 1.0) - g * q;
                        g = q * (e + 1.0) + p * g;
                        n--;
                    }
                    f += 1.0;
                    d = f * f + g * g;
                    pa = f / d;
                    qa = -g / d;
                    d = a + 0.5 - p;
                    q += x;
                    pa1 = (pa * q - qa * d) / x;
                    qa1 = (qa * q + pa * d) / x;
                }
                else
                {
                    double c, s, chi, ya = 0.0, ya1 = 0.0;
                    double[] ja = new double[2];
                    b = Math.Sqrt(pi * x / 2.0);
                    chi = x - pi * (a / 2.0 + 0.25);
                    c = Math.Cos(chi);
                    s = Math.Sin(chi);
                    bessya01(a, x, ref ya, ref ya1);
                    bessjaplusn(a, x, 1, ja);
                    pa = b * (ya * s + c * ja[0]);
                    qa = b * (c * ya - s * ja[0]);
                    pa1 = b * (s * ja[1] - c * ya1);
                    qa1 = b * (c * ja[1] + s * ya1);
                }
                if (rec)
                {
                    x = 2.0 / x;
                    b = (a + 1.0) * x;
                    for (n = 1; n <= na; n++)
                    {
                        p0 = pa - qa1 * b;
                        q0 = qa + pa1 * b;
                        pa = pa1;
                        pa1 = p0;
                        qa = qa1;
                        qa1 = q0;
                        b += x;
                    }
                }
                if (rev)
                {
                    p0 = pa1;
                    pa1 = pa;
                    pa = p0;
                    q0 = qa1;
                    qa1 = qa;
                    qa = q0;
                }
            }
        }

        public void besszeros(double a, int n, double[] z, int d)
        {
            int j, s;
            double aa, a2, b, bb, c, chi, co, mu, mu2, mu3, mu4, p, pi, pa = 0.0, pa1 = 0.0, p0, p1, pp1,
                    q, qa = 0.0, qa1 = 0.0, q1, qq1, ro, si, t, tt, u, v, w, x, xx, x4, y, yy, fi;

            pi = Math.PI;
            aa = a * a;
            mu = 4.0 * aa;
            mu2 = mu * mu;
            mu3 = mu * mu2;
            mu4 = mu2 * mu2;
            if (d < 3)
            {
                p = 7.0 * mu - 31.0;
                p0 = mu - 1.0;
                p1 = 4.0 * (253.0 * mu2 - 3722.0 * mu + 17869.0) / 15.0 / p * p0;
                q1 = 8.0 * (83.0 * mu2 - 982.0 * mu + 3779.0) / 5.0 / p;
            }
            else
            {
                p = 7.0 * mu2 + 82.0 * mu - 9.0;
                p0 = mu + 3.0;
                p1 = (4048.0 * mu4 + 131264.0 * mu3 - 221984.0 * mu2 -
                    417600.0 * mu + 1012176.0) / 60.0 / p;
                q1 = 1.6 * (83.0 * mu3 + 2075.0 * mu2 - 3039.0 * mu + 3537.0) / p;
            }
            t = (d == 1 || d == 4) ? 0.25 : 0.75;
            tt = 4.0 * t;
            if (d < 3)
            {
                pp1 = 5.0 / 48.0;
                qq1 = -5.0 / 36.0;
            }
            else
            {
                pp1 = -7.0 / 48.0;
                qq1 = 35.0 / 288.0;
            }
            y = 3.0 * pi / 8.0;
            bb = (a >= 3.0) ? Math.Pow(a, -2.0 / 3.0) : 0.0;
            for (s = 1; s <= n; s++)
            {
                if (a == 0.0 && s == 1 && d == 3)
                {
                    x = 0.0;
                    j = 0;
                }
                else
                {
                    if (s >= 3.0 * a - 8.0)
                    {
                        b = (s + a / 2.0 - t) * pi;
                        c = 1.0 / b / b / 64.0;
                        x = b - 1.0 / b / 8.0 * (p0 - p1 * c) / (1.0 - q1 * c);
                    }
                    else
                    {
                        if (s == 1)
                            x = ((d == 1) ? -2.33811 : ((d == 2) ? -1.17371 :
                                    ((d == 3) ? -1.01879 : -2.29444)));
                        else
                        {
                            x = y * (4.0 * s - tt);
                            v = 1.0 / x / x;
                            x = -Math.Pow(x, 2.0 / 3.0) * (1.0 + v * (pp1 + qq1 * v));
                        }
                        u = x * bb;
                        yy = 2.0 / 3.0 * Math.Pow(-u, 1.5);
                        if (yy == 0.0)
                            fi = 0.0;
                        else if (yy > 1.0e5)
                            fi = 1.570796;
                        else
                        {
                            double r, pp;
                            if (yy < 1.0)
                            {
                                p = Math.Pow(3.0 * yy, 1.0 / 3.0);
                                pp = p * p;
                                p *= (1.0 + pp * (-210.0 + pp * (27.0 - 2.0 * pp)) / 1575.0);
                            }
                            else
                            {
                                p = 1.0 / (yy + 1.570796);
                                pp = p * p;
                                p = 1.570796 - p * (1.0 + pp * (2310.0 + pp * (3003.0 + pp *
                                    (4818.0 + pp * (8591.0 + pp * 16328.0)))) / 3465.0);
                            }
                            pp = (yy + p) * (yy + p);
                            r = (p - Math.Atan(p + yy)) / pp;
                            fi = p - (1.0 + pp) * r * (1.0 + r / (p + yy));
                        }
                        v = fi;
                        w = 1.0 / Math.Cos(v);
                        xx = 1.0 - w * w;
                        c = Math.Sqrt(u / xx);
                        x = w * (a + c / a / u * ((d < 3) ?
                            -5.0 / 48.0 / u - c * (-5.0 / 24.0 / xx + 1.0 / 8.0) :
                            7.0 / 48.0 / u + c * (-7.0 / 24.0 / xx + 3.0 / 8.0)));
                    }
                    j = 0;
                    do
                    {
                        xx = x * x;
                        x4 = xx * xx;
                        a2 = aa - xx;
                        besspqa01(a, x, ref pa, ref qa, ref pa1, ref qa1);
                        chi = x - pi * (a / 2.0 + 0.25);
                        si = Math.Sin(chi);
                        co = Math.Cos(chi);
                        ro = ((d == 1) ? (pa * co - qa * si) / (pa1 * si + qa1 * co) :
                                ((d == 2) ? (pa * si + qa * co) / (qa1 * si - pa1 * co) :
                                ((d == 3) ? a / x - (pa1 * si + qa1 * co) / (pa * co - qa * si) :
                                                a / x - (qa1 * si - pa1 * co) / (pa * si + qa * co))));
                        j++;
                        if (d < 3)
                        {
                            u = ro;
                            p = (1.0 - 4.0 * a2) / 6.0 / x / (2.0 * a + 1.0);
                            q = (2.0 * (xx - mu) - 1.0 - 6.0 * a) / 3.0 / x / (2.0 * a + 1.0);
                        }
                        else
                        {
                            u = -xx * ro / a2;
                            v = 2.0 * x * a2 / (aa + xx) / 3.0;
                            w = a2 * a2 * a2;
                            q = v * (1.0 + (mu2 + 32.0 * mu * xx + 48.0 * x4) / 32.0 / w);
                            p = v * (1.0 + (-mu2 + 40.0 * mu * xx + 48.0 * x4) / 64.0 / w);
                        }
                        w = u * (1.0 + p * ro) / (1.0 + q * ro);
                        x += w;
                    } while (Math.Abs(w / x) > 1.0e-13 && j < 5);
                }
                z[s - 1] = x;
            }
        }
    }
}
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace SteadyStateTempCylinder
{
    public partial class DrawGraphForm : Form
    {
        private const double epsilon = 1.0e-2;
        private double xMax;
        private double yMax;
        private int n;
        private Brush brush;
        private Brush potBrush;
        private Font font;
        private Pen pen1, pen2;
        private List<PotPoint> pts;

        public DrawGraphForm(
            double xMax,
            double yMax,
            List<PotPoint> pts)
        {
            InitializeComponent();
            this.xMax = xMax;
            this.yMax = yMax;
            this.pts = pts;
            n = pts.Count;
            brush = new SolidBrush(Color.Black);
            potBrush = new SolidBrush(Color.Red);
            pen1 = new Pen(Color.Black);
            pen2 = new Pen(Color.Blue);
            font = new Font("Courier New", 12f, FontStyle.Bold);
            panel1.Paint += new PaintEventHandler(PanelPaintHandler);
        }

        private void DrawGraph(float u0, float v0,
            float u1, float v1,
            Graphics g)
        {
            try
            {
                float xMin = u0;
                float yMin = v0;
                float xMax = u1;
                float yMax = v1;

                float xSpan = xMax - xMin;
                float ySpan = yMax - yMin;

                float deltaX = xSpan / 8.0f;
                float deltaY = ySpan / 8.0f;
                float height = panel1.Height;
                float width = panel1.Width;

                float sx0 = 2f * width / 16f;
                float sx1 = 14f * width / 16f;
                float sy0 = 2f * height / 16f;
                float sy1 = 14f * height / 16f;

                float xSlope = (sx1 - sx0) / xSpan;
                float xInter = sx0 - xSlope * xMin;
                float ySlope = (sy0 - sy1) / ySpan;
                float yInter = sy0 - ySlope * yMax;

                float x = xMin;
                float y = yMin;

                string fTitle = "Graph of Constant u";

                float w = g.MeasureString(fTitle, font).Width;
                float h = g.MeasureString(fTitle, font).Height;

                g.DrawString(fTitle, font, brush,
                    (width - w) / 2f, h);

                string xTitle = "r";
                w = g.MeasureString(xTitle, font).Width;
                g.DrawString(xTitle, font, brush,
                    sx0 + (sx1 - sx0 - w) / 2f, sy1 + h + h);

                string yTitle = "z";
                w = g.MeasureString(yTitle, font).Width;
                g.DrawString(yTitle, font, brush,
                    sx1 + w / 5f, sy0 + (sy1 - sy0) / 2f - h / 2f);

                int i = 0;

                while (i <= 8)
                {
                    float sx = xSlope * x + xInter;
                    string s = string.Format("{0,5:0.00}", x);

                    g.DrawLine(pen1, sx, sy0, sx, sy1);

                    w = g.MeasureString(s, font).Width;
                    g.DrawString(s, font, brush,
                        sx - w / 2, sy1 + h / 2f);
                    x += deltaX;
                    i++;
                }

                i = 0;

                while (i <= 8)
                {
                    float sy = ySlope * y + yInter;
                    string s = string.Format("{0,5:0.00}", y);

                    w = g.MeasureString(s, font).Width;
                    g.DrawLine(pen1, sx0, sy, sx1, sy);
                    g.DrawString(s, font, brush,
                        sx0 - w - w / 5f, sy - h / 2f);
                    y += deltaY;
                    i++;
                }

                g.Clip = new Region(new RectangleF(
                    sx0, sy0, (sx1 - sx0), (sy1 - sy0)));

                for (i = 0; i < n; i++)
                {
                    float px = (float)pts[i].X;
                    float py = (float)pts[i].Y;
                    float pu = (float)pts[i].U;

                    if (Math.Abs(pu + 0.05) < epsilon ||
                        Math.Abs(pu + 0.10) < epsilon ||
                        Math.Abs(pu + 0.15) < epsilon ||
                        Math.Abs(pu + 0.20) < epsilon ||
                        Math.Abs(pu + 0.25) < epsilon ||
                        Math.Abs(pu + 0.30) < epsilon ||
                        Math.Abs(pu + 0.35) < epsilon ||
                        Math.Abs(pu + 0.40) < epsilon ||
                        Math.Abs(pu + 0.45) < epsilon ||
                        Math.Abs(pu + 0.50) < epsilon ||
                        Math.Abs(pu + 0.55) < epsilon ||
                        Math.Abs(pu + 0.60) < epsilon ||
                        Math.Abs(pu + 0.55) < epsilon ||
                        Math.Abs(pu + 0.70) < epsilon ||
                        Math.Abs(pu + 0.75) < epsilon ||
                        Math.Abs(pu + 0.80) < epsilon ||
                        Math.Abs(pu + 0.85) < epsilon ||
                        Math.Abs(pu + 0.90) < epsilon ||
                        Math.Abs(pu + 0.95) < epsilon ||
                        Math.Abs(pu - 0.05) < epsilon ||
                        Math.Abs(pu - 0.10) < epsilon ||
                        Math.Abs(pu - 0.15) < epsilon ||
                        Math.Abs(pu - 0.20) < epsilon ||
                        Math.Abs(pu - 0.25) < epsilon ||
                        Math.Abs(pu - 0.30) < epsilon ||
                        Math.Abs(pu - 0.35) < epsilon ||
                        Math.Abs(pu - 0.40) < epsilon ||
                        Math.Abs(pu - 0.45) < epsilon ||
                        Math.Abs(pu - 0.50) < epsilon ||
                        Math.Abs(pu - 0.55) < epsilon ||
                        Math.Abs(pu - 0.60) < epsilon ||
                        Math.Abs(pu - 0.55) < epsilon ||
                        Math.Abs(pu - 0.70) < epsilon ||
                        Math.Abs(pu - 0.75) < epsilon ||
                        Math.Abs(pu - 0.80) < epsilon ||
                        Math.Abs(pu - 0.85) < epsilon ||
                        Math.Abs(pu - 0.90) < epsilon ||
                        Math.Abs(pu - 0.95) < epsilon)
                    {
                        float sx = xSlope * px + xInter;
                        float sy = ySlope * py + yInter;

                        g.FillEllipse(potBrush, (float)sx, (float)sy, 2.0f, 2.0f);
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString(), "Warning Message",
                    MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
        }

        private void LayOutTheForm()
        {
            // layout the panel

            int w = ClientSize.Width;
            int h = ClientSize.Height;

            panel1.Width = w;
            panel1.Height = h;
            panel1.Location = new Point(0, 0);
            panel1.Invalidate();
        }

        protected void PanelPaintHandler(object sender, PaintEventArgs pa)
        {
            DrawGraph((float)0.0, (float)0.0, (float)xMax, (float)yMax, pa.Graphics);
        }

        protected override void OnResize(EventArgs ea)
        {
            LayOutTheForm();
        }
    }
}
using System;

namespace SteadyStateTempCylinder
{
    public class PotPoint : IComparable
    {
        private double x, y, u;

        public double X
        {
            get
            {
                return x;
            }
            set
            {
                x = value;
            }
        }

        public double Y
        {
            get
            {
                return y;
            }
            set
            {
                y = value;
            }
        }

        public double U
        {
            get
            {
                return u;
            }
            set
            {
                u = value;
            }
        }

        public PotPoint(double x, double y, double u)
        {
            this.x = x;
            this.y = y;
            this.u = u;
        }

        public int CompareTo(object obj)
        {
            if (obj == null)
                return 1;

            PotPoint pp = (PotPoint)obj;

            if (u > pp.u)
                return 1;
            else if (u == pp.u)
                return 0;
            else
                return -1;
        }
    }
}

Counting and Enumerating the Number of Divisors of a Natural Number by James Pate Williams, Jr.

A simple number theoretic problem is to count and enumerate the number of divisors of a natural number which is the set { 1, 2, 3, … }. An Order(n) method is to find all numbers between 1 and n such that the number divides n. If you have the prime factorization of n then the number of divisors is the product of the prime factorization (exponents + 1). For example the divisors of 100 are:

1 2 4 5 10 20 25 50 100

The prime factorization of 100 = 2^2 * 5 ^ 2. So the number of divisors is (2 + 1) * (2 + 1) = 9.

Below is a C++ implementation of an algorithm to enumerate and count the number of divisors of a natural number and count the divisors by using the factorization found by trial division.

#include <algorithm>
#include <chrono>
#include <iostream>
#include <vector>
using namespace std;

const int B0 = 10000000;

bool sieve[B0 + 1];
vector<int> prime, divisors, expon, primes, primesSquares;

void Sieve()
{
	// Sieve of Eratosthenes
	// find all prime numbers
	// less than or equal B0

	int c = 3, i, inc;

	sieve[2] = true;

	for (i = 3; i <= B0; i++)
		if (i % 2 == 1)
			sieve[i] = true;

	do
	{
		i = c * c;
		inc = c + c;

		while (i <= B0)
		{
			sieve[i] = false;

			i += inc;
		}

		c += 2;

		while (!sieve[c])
			c++;

	} while (c * c <= B0);

	for (i = 2; i <= B0; i++)
	{
		if (sieve[i])
		{
			primes.push_back(i);
			primesSquares.push_back(i * i);
		}
	}
}

bool TrialDivision(int number)
{
	int bound = B0; // (int)sqrt(number);

	for (int i = 0; i < (int)primes.size(); i++)
	{
		int p = primes[i];

		if (p <= bound)
		{
			if (number % p == 0)
			{
				int e = 0;

				while (number % p == 0)
				{
					e++;
					number /= p;
				}

				prime.push_back(p);
				expon.push_back(e);
			}

			if (number == 1)
				return true;
		}
	}

	return false;
}

void GetDivisors(int n, int count)
{
	divisors.push_back(1);

	for (int i = 0; i < (int)prime.size(); i++)
	{
		int p = prime[i];

		for (int j = 1; j <= (int)expon[i]; j++)
		{
			int q = (int)pow(p, j);

			divisors.push_back(q);
		}
	}

	bool done = false;
	int limit;

	do
	{
		limit = (int)divisors.size();

		for (int i = 1; i < limit - 1; i++)
		{
			int di = divisors[i];

			for (int j = i + 1; !done && j < limit; j++)
			{
				int dj = divisors[j], product = di * dj;
				vector<int>::iterator it =
					find(divisors.begin(), divisors.end(), product);

				if (it == divisors.end())
				{
					if (divisors.size() < count &&
						product <= n && n % product == 0)
						divisors.push_back(product);

					else if (divisors.size() == count)
						done = true;
				}
			}
		}
	} while (!done);

	std::sort(divisors.begin(), divisors.end());
}

int main()
{
	int count = 0, number;

	std::cout << "Enter a number = ";
	cin >> number;
	std::cout << endl;

	auto start = chrono::high_resolution_clock::now();

	for (int i = 1; i <= number; i++)
	{
		if (number % i == 0)
		{
			cout << i << ' ';
			count++;
		}
	}

	auto finish = chrono::high_resolution_clock::now();

	std::cout << endl << endl;
	std::cout << "Divisor count = " << count << endl << endl;

	chrono::duration<double> elapsed = finish - start;

	std::cout << "Elapsed time = " << elapsed.count()
		<< " seconds" << endl << endl;

	start = chrono::high_resolution_clock::now();

	Sieve();

	if (!TrialDivision(number))
	{
		cout << "Trial division failed!" << endl;
		return 0;
	}

	count = 1;

	for (int i = 0; i < (int)expon.size(); i++)
		count *= expon[i] + 1;

	finish = chrono::high_resolution_clock::now();

	std::cout << "Divisor count = " << count << endl << endl;

	GetDivisors(number, count);

	for (int i = 0; i < (int)divisors.size(); i++)
		std::cout << divisors[i] << " ";

	std::cout << endl << endl;

	elapsed = finish - start;

	std::cout << "Elapsed time = " << elapsed.count()
		<< " seconds" << endl;
}

On Jigsaw Puzzle Solving and Computer Chess by James Pate Williams, Jr.

I have been playing a jigsaw puzzle app on my Microsoft desktop. The name of the app is “Jigsaw Puzzle HD”. I get one free puzzle per day. I set the number of pieces to 49 which is a 7 by 7 square. It takes me approximately 10 to 20 minutes to solve puzzle. The pieces are large on my Dell display but there is not room to spare using a maximized window and 49 pieces.

Here are some tips I have learned about jigsaw puzzle solving (an algorithm):

  • Roughly separate the pieces by color
  • Separate the four boundaries out from the sorted pieces
  • Construct the four boundaries of the puzzle
  • Use a sharper color sort to really untangle the middle pieces
  • Solve small areas of the middle of the puzzle
  • Iterate the preceding steps until the solution is found

I have a nice chess playing app on my desktop computer named “The Chess Lv. 100”. This chess game has 100 levels and Level 1’s Rating is 258 and Level 100’s Rating is 2300. I have a Level 12 Rating of 849 which is probably lower than my United States Chess Federation Rating back in the era 1968 to 1971. I play Level 8 to 12 computer opponents and sometimes venture as high as Level 25 which has a rating of 1094. Here is some information about the United States Chess Federation ratings:

US Chess Federation:

I do not have a simple algorithm for chess, but do not make blunders and try to look several moves into future before you move. Also a good working knowledge of openings, middle-games, and end-games helps.