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PermutationGetRowsOfPlainChanges Method

Iterate thru all rows of the Permutation table while swapping only 2 values in each result.

Namespace:  Kaos.Combinatorics
Assembly:  KaosCombinatorics (in KaosCombinatorics.dll) Version: 5.0.0.6
Syntax
C#
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public IEnumerable<Permutation> GetRowsOfPlainChanges()

Return Value

Type: IEnumerablePermutation
An iterator for a Permutation table.
Exceptions
ExceptionCondition
InvalidOperationException When Choices not equal to Picks.
Remarks

The results of this iterator are commonly known as "plain changes".

Usage note:

  • Using this iterator will not perform as fast as using a class that is designed and optimized for generating plain changes without the overhead of calculating the lexicographical rank for each row.

Examples
C#
Copy
using System;
using Kaos.Combinatorics;

namespace ExampleApp
{
    class PnExample07
    {
        static void Main()
        {
            var pn = new Permutation (4);

            Console.WriteLine ($"Plain changes, n={pn.Choices}:\n");

            foreach (var row in pn.GetRowsOfPlainChanges())
                Console.WriteLine ($"{row.PlainRank,2}: {row}  Swaps={row.Swaps}, Rank={row.Rank}");
        }

        /* Output:

        Plain changes, n=4:

         0: { 0, 1, 2, 3 }  Swaps=0, Rank=0
         1: { 0, 1, 3, 2 }  Swaps=1, Rank=1
         2: { 0, 3, 1, 2 }  Swaps=2, Rank=4
         3: { 3, 0, 1, 2 }  Swaps=3, Rank=18
         4: { 3, 0, 2, 1 }  Swaps=2, Rank=19
         5: { 0, 3, 2, 1 }  Swaps=1, Rank=5
         6: { 0, 2, 3, 1 }  Swaps=2, Rank=3
         7: { 0, 2, 1, 3 }  Swaps=1, Rank=2
         8: { 2, 0, 1, 3 }  Swaps=2, Rank=12
         9: { 2, 0, 3, 1 }  Swaps=3, Rank=13
        10: { 2, 3, 0, 1 }  Swaps=2, Rank=16
        11: { 3, 2, 0, 1 }  Swaps=3, Rank=22
        12: { 3, 2, 1, 0 }  Swaps=2, Rank=23
        13: { 2, 3, 1, 0 }  Swaps=3, Rank=17
        14: { 2, 1, 3, 0 }  Swaps=2, Rank=15
        15: { 2, 1, 0, 3 }  Swaps=1, Rank=14
        16: { 1, 2, 0, 3 }  Swaps=2, Rank=8
        17: { 1, 2, 3, 0 }  Swaps=3, Rank=9
        18: { 1, 3, 2, 0 }  Swaps=2, Rank=11
        19: { 3, 1, 2, 0 }  Swaps=1, Rank=21
        20: { 3, 1, 0, 2 }  Swaps=2, Rank=20
        21: { 1, 3, 0, 2 }  Swaps=3, Rank=10
        22: { 1, 0, 3, 2 }  Swaps=2, Rank=7
        23: { 1, 0, 2, 3 }  Swaps=1, Rank=6

        */
    }
}
See Also