Example #1
0
        public void TestCnFromCnMinusOne()
        {
            UInt32[] CnMinusOne = new UInt32[] { 1, 3, 5, 7 };
            UInt32[] Cn         = new UInt32[3];

            UInt32 CnLength;

            Coprimes.CnMinusOneToCn(CnMinusOne, (UInt32)CnMinusOne.Length, Cn, out CnLength);

            Assert.AreEqual(3U, CnLength);
            Assert.AreEqual(1U, Cn[0]);
            Assert.AreEqual(5U, Cn[1]);
            Assert.AreEqual(7U, Cn[2]);
        }
        static Int32 Main(string[] args)
        {
            //
            // Process command line arguments
            //
            Options       options       = new Options();
            List <String> nonOptionArgs = options.Parse(args);

            if (nonOptionArgs.Count <= 0)
            {
                options.PrintUsage();
                return(1);
            }
            if (nonOptionArgs.Count != 1)
            {
                return(options.ErrorAndUsage("Expected {0} non-option arguments but got {1}",
                                             1, nonOptionArgs.Count));
            }

            UInt32 MaxNumber = UInt32.Parse(nonOptionArgs[0]);

            if (MaxNumber == 0)
            {
                return(options.ErrorAndUsage("MaxNumber cannot be 0"));
            }

            UInt32 C1Length = (MaxNumber + (((MaxNumber % 2) == 1) ? (UInt32)1 : 0)) / 2;

            //
            // Generate the primes
            //
            Console.WriteLine("Allocating two arrays of length {0}...", C1Length);
            UInt32[] coprimes1 = new UInt32[C1Length];
            UInt32[] coprimes2 = new UInt32[C1Length];
            Console.WriteLine("Done allocating memory");


            Int64 sequenceGenerationStartTime = Stopwatch.GetTimestamp();

            //
            // InitializeCoprimes1
            //
            UInt32 sum = 1;

            for (UInt32 i = 0; i < C1Length; i++)
            {
                coprimes1[i] = sum;
                sum         += 2;
            }

            //
            // Generate sequence
            //
            UInt32 coprimes1Length = C1Length, coprimes2Length;
            UInt32 n = 1;
            UInt32 Pn;

            while (true)
            {
                Coprimes.CnMinusOneToCn(coprimes1, coprimes1Length, coprimes2, out coprimes2Length);
                n++;

                Pn = coprimes2[2];
                if (Pn * Pn > coprimes1[coprimes1Length - 1])
                {
                    Console.WriteLine("Pn {0}, coprimes.length = {1}, coprimes[last] = {2}, n = {3}",
                                      Pn, coprimes1Length, coprimes1[coprimes1Length - 1], n);
                    n += coprimes1Length;
                    Pn = coprimes1[coprimes1Length - 1];
                    break;
                }

                Coprimes.CnMinusOneToCn(coprimes2, coprimes2Length, coprimes1, out coprimes1Length);
                n++;

                Pn = coprimes1[2];
                if (Pn * Pn > coprimes2[coprimes2Length - 1])
                {
                    Console.WriteLine("Pn {0}, coprimes.length = {1}, coprimes[last] = {2}, n = {3}",
                                      Pn, coprimes2Length, coprimes2[coprimes2Length - 1], n);
                    n += coprimes2Length;
                    Pn = coprimes2[coprimes2Length - 1];
                    break;
                }
            }

            //
            // Print sequence generation time
            //
            Int64 sequenceGenerationEndTime = Stopwatch.GetTimestamp();

            Console.WriteLine("Sequence Generation Time: {0} milliseconds",
                              (sequenceGenerationEndTime - sequenceGenerationStartTime).StopwatchTicksAsUInt32Milliseconds());

            //
            // Print the nth prime number
            //
            Console.WriteLine("Prime {0} is equal to {1}", n, Pn);

            return(0);
        }