Genetic Algorithm

thomash16 (3)
Hello I'm writing a genetic algorithm code to create a string. I run the code and it gets pretty close to my target, but then says the fitness is 1 when it is obviously not. Please help!

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#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
#include <array>
#include <cstring>

using namespace std;

const int MAX_LOOP = 2000;  // max count of iterations
const int MAX_POOL = 2000;  // max size of matingpool[]
const int POP_COUNT = 200;  // max count of organisms in the pool

/* ASCII-values of SPACE, A-Z, a-z.
 */
const char alphanum[53] =
{   32, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81,
    82, 83, 84, 85, 86, 87, 88, 89, 90, 97, 98, 99, 100, 101, 102, 103, 104,
    105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118,
    119, 120, 121, 122
};
 
/* Creates strings of length 'length', filled with randomly choosen
 * alpanumeric characters.
 */
void
buildPopulation (string population[], int length)
{

    int z;
    int i;
    int a;
    string organism = "";

    i = 0;
    z = 1;
    while (z <= POP_COUNT)
    {
        organism = "";
        for (int a = 1; a <= length; a++)
        {
            organism = organism + alphanum[rand () % 52];
        }
        population[i] = organism;
        i++;
        z++;
    }
}

/* Calculates the divergence between each 'population[i] string
 *    and string 'desired'.
 * 'percpop' array becomes fitness level (between 0 and 1).
 * 'numpop' becomes for each letter which matches the letter of
 *    'desired' a 1, otherwhise a 0.
 * 'length holds the length of the organisms.
 */
void
calculatefitness (string population[], int length, string desired,
                  double percpop[], string numpop[])
{
    double counter = 0;
    string organism;
    string numorgan;
    double maxfit = 0;

    for (int i = 0; i < POP_COUNT; i++)
    {
        organism = population[i];
        for (int j = 0; j < length; j++)
        {
            if (organism.at (j) == desired.at (j))
            {
                organism[j] = {'1' };
            }
            else
            {
                organism[j] = { '0' };
            }
        }
        numpop[i] = organism;
    }
    for (int a = 0; a < 200; a++)
    {
        counter = 0;
        numorgan = numpop[a];
        for (int b = 0; b < length; b++)
        {
            if (numorgan.at (b) == '1')
            {
                counter++;
            }
        }
        percpop[a] = (counter) / (length);
    }
}

/* Fills mating pool from first -1-found with 'copy' counts
 * of value 'index'.
 */
void
otherticketinsert (int matingpool[], int index, int copy)
{
    for (int i = 0; i < MAX_POOL; i++)
    {
        if (matingpool[i] == -1)
        {
            for (int j = 0; j < copy; j++)
            {
                matingpool[i + j] = index;
            }
            break;
        }
    }
}


/* Fills matingpool[] with copys of percpop[], taking account
 * of the fitness oft the populations.
 */
void
buildMatingPool (double percpop[], int matingpool[], double normalpop[],
                 int factor)
{
    double largest = 0;
    int copy;

    for (int i = 0; i < POP_COUNT; i++)
    {
        if (largest < percpop[i])
        {
            largest = percpop[i];
        }
    }
    for (int j = 0; j < POP_COUNT; j++)
    {
        normalpop[j] = percpop[j] / largest;
    }
    for (int index = 0; index < POP_COUNT; index++)
    {
        copy = normalpop[index] * factor;
        otherticketinsert (matingpool, index, copy);
    }
}

/* Working is still unclear to me!
 */
string breed (string population[], int matingpool[],
              int desiredlength)
{

    int ticketsgiven;
    string child;
    int w, x, y, z;
    string a, b, c, d;

    for (int m = 0; m < MAX_POOL; m++)
    {
        if (matingpool[m] == -1)
        {
            ticketsgiven = (m - 1);
            break;
        }
        else
        {
            ticketsgiven = MAX_LOOP;
        }
    }
    int realparents[ticketsgiven] = { 0 };
    for (int n = 0; n < ticketsgiven; n++)
    {
        realparents[n] = matingpool[n];
    }
    w = realparents[rand () % ticketsgiven + 0];
    x = realparents[rand () % ticketsgiven + 0];
    y = rand () % (desiredlength - 1) + 0;
    a = population[w];
    b = population[x];
    a.erase ((y + 1), (desiredlength));
    b.erase (0, y + 1);
    c = a + b;
    child = c;
    
    return child;
}

/* Possibly mutates the string at a random position with a random value.
 */
string mutation (string child, int length)
{
    int x = rand () % 100 + 1;

    if (x <= 4)
    {
        char z = alphanum[rand () % 52];
        int y = rand () % (length - 1) + 0;
        child[y] = z;
    }
    return child;
}


void
resetMatingPool ( int matingpool[] )
{
    for (int idx = 0; idx < 2000; idx++)
    {
        matingpool[idx] = -1;
    }
}

int
main ()
{
    srand ( time ( nullptr ) );
    int counter;
    int i;
    int length;
    int factor = 10;
    string child;
    string mutatedchild;
    double largest = 0;
    string desired = { "" };
    
    int matingpool[2000];
    resetMatingPool (matingpool);
    

    double percpop[200] = { 0 };
    double normalpop[200] = { 0 };
    string population[200] = { "" };
    string numpop[200] = { "" };
    string children[200] = { "" };

    cout << "What would you like me to say?" << endl;
    getline (cin, desired);

    length = desired.size ();
    buildPopulation (population, length);

    for (int u = 0; u < 2000; u++)
    {
        counter++;
        calculatefitness (population, length, desired, percpop, numpop);
        resetMatingPool( matingpool );
        buildMatingPool (percpop, matingpool, normalpop, factor);

        for (int i = 0; i < 200; i++)
        {
            if (largest < percpop[i])
            {
                largest = percpop[i];
            }
        }

        cout << "Generation : " << counter 
             << ", Fitness : " << largest << endl;

        for (int k = 0; k < POP_COUNT; k++)
        {
            child = breed (population, matingpool, length);
            mutatedchild = mutation (child, length);
            children[k] = mutatedchild;
        }
        for (int j = 0; j < POP_COUNT; j++)
        {
            population[j] = children[j];
        }
        for(int p = 0 ; p < 200 ; p++)
        {
            if(percpop[p] == largest)
            {
                cout << population[p] << endl;
            }
        }
        if (largest >= 1.0) break;
    }
    if (counter < 2000)
    {
        cout << "Fitness of 1 was reached at generation : " << counter <<
         endl;
    }
    else
    {
        cout << "A Fitness of 1 was within " << MAX_LOOP
             << " loops never reached!\n";
    }
}
nuderobmonkey (640)
Found the error: Before 'largest' should be evaluated, there should be 'calculatefitness()' get invoked.
If not, then the array entries will in a wrong state.
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#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
#include <array>
#include <cstring>

using namespace std;

const int MAX_LOOP = 2000;  // max count of iterations
const int POP_COUNT = 200;  // max count of organisms in the pool
constexpr int MAX_POOL = POP_COUNT * 10;  // max size of matingpool[]

/* ASCII-values of SPACE, A-Z, a-z.
 */
const char alphanum[53] =
{   32, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81,
    82, 83, 84, 85, 86, 87, 88, 89, 90, 97, 98, 99, 100, 101, 102, 103, 104,
    105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118,
    119, 120, 121, 122
};
 
/* Creates strings of length 'length', filled with randomly choosen
 * alpanumeric characters.
 */
void
buildPopulation (string population[], int length)
{   
    for (int i = 0; i < POP_COUNT; ++i)
    {
        string organism;
        
        for (int a = 1; a <= length; a++)
        {
            organism = organism + alphanum[rand () % 52];
        }
        population[i] = organism;
    }
}

/* Calculates the divergence between each 'population[i] string
 *    and string 'desired'.
 * 'percpop' array becomes fitness level (between 0 and 1).
 * 'numpop' becomes for each letter which matches the letter of
 *    'desired' a '1', otherwhise a '0'.
 * 'length holds the length of the organisms.
 */
void
calculatefitness (string population[], int length, string desired,
                  double percpop[], string numpop[])
{
    double counter = 0;  // count the matches inside 'organism'
    string organism;
    string numorgan;

    for (int i = 0; i < POP_COUNT; i++)
    {
        organism = population[i];
        for (int j = 0; j < length; j++)
        {
            if (organism.at (j) == desired.at (j))
            {
                organism[j] = { '1' };
            }
            else
            {
                organism[j] = { '0' };
            }
        }
        numpop[i] = organism;
    }
    for (int a = 0; a < 200; a++)
    {
        counter = 0;
        numorgan = numpop[a];
        for (int b = 0; b < length; b++)
        {
            if (numorgan.at (b) == '1')
            {
                counter++;
            }
        }
        percpop[a] = (counter) / (length);
    }
}

/* Fills mating pool from first -1-found with 'copy' counts
 * of value 'index'.
 */
void
otherticketinsert (int matingpool[], int index, int copy)
{
    for (int i = 0; i < MAX_POOL; i++)
    {
        if (matingpool[i] == -1)
        {
            for (int j = 0; j < copy; j++)
            {
                matingpool[i + j] = index;
            }
            break;
        }
    }
}

/* Fills matingpool[] with percpop[] indice, taking account
 * of the fitness oft the populations.
 */
void
buildMatingPool (double percpop[], int matingpool[], double normalpop[],
                 int factor)
{
    double largest = 0;
    int copy;

    for (int i = 0; i < POP_COUNT; i++)
    {
        if (largest < percpop[i])
        {
            largest = percpop[i];
        }
    }
    for (int j = 0; j < POP_COUNT; j++)
    {
        normalpop[j] = percpop[j] / largest;
    }
    for (int index = 0; index < POP_COUNT; index++)
    {
        copy = normalpop[index] * factor;
        otherticketinsert (matingpool, index, copy);
    }
}

/* Splices a string from two randomly choosen strings from pool ticket
 * to a new 'child' string.
 */
string breed (string population[], int matingpool[],
              int desiredlength)
{

    int ticketsgiven;   // fill count of matingpool[]
    string child;
    int w, x, y;
    string a, b;

    ticketsgiven = MAX_POOL;
    for (int m = 0; m < MAX_POOL; m++)
    {
        if (matingpool[m] == -1)
        {
            ticketsgiven = m;
            break;
        }
    }
    int realparents[ticketsgiven] = { 0 };
    for (int n = 0; n < ticketsgiven; n++)
    {
        realparents[n] = matingpool[n];
    }
    w = realparents[rand () % ticketsgiven];
    x = realparents[rand () % ticketsgiven];
    y = rand () % (desiredlength - 1);
    a = population[w];
    b = population[x];
    a.erase ((y + 1), (desiredlength));
    b.erase (0, y + 1);
    child = a + b;
    
    return child;
}

/* Possibly mutates the string at a random position with a random value.
 */
string mutation (string child, int length)
{
    int x = rand () % 100 + 1;

    if (x <= 4)
    {
        char z = alphanum[rand () % 52];
        int y = rand () % (length - 1) + 0;
        child[y] = z;
    }
    return child;
}


void
resetMatingPool ( int matingpool[] )
{
    for (int idx = 0; idx < 2000; idx++)
    {
        matingpool[idx] = -1;
    }
}

int
main ()
{
    srand ( time ( nullptr ) );
    int counter;       // counts the iterations
    int i;
    int idx;            // index to observe organisms at organism
    int length;         // string length
    int factor = 10;
    string child;
    string mutatedchild;
    double largest = 0;      //  largest percentage of matches
    string desired = { "" };  // desired string, goal
    
    int matingpool[2000];
    resetMatingPool (matingpool);
    

    double percpop[200] = { 0 };
    double normalpop[200] = { 0 };
    string population[200] = { "" };
    string numpop[200] = { "" };
    string children[200] = { "" };
    string probe;

    cout << "What would you like me to say?" << endl;
    getline (cin, desired);

    length = desired.size ();
    buildPopulation (population, length);
    calculatefitness (population, length, desired, percpop, numpop);

    for (int u = 0; u < 2000; u++)
    {
        counter++;
        resetMatingPool (matingpool);
        buildMatingPool (percpop, matingpool, normalpop, factor);


        for (int k = 0; k < POP_COUNT; k++)
        {
            child = breed (population, matingpool, length);
            population[k] = mutation (child, length);

        }
        calculatefitness (population, length, desired, percpop, numpop);
        for ( i = 0; i < 200; i++)
        {
            if (largest < percpop[i])
            {
                largest = percpop[i];
                probe = population[i];
                idx = i;
            }
        }   
/* DEBUG
        cout << population[idx] 
             <<", percpop:["<<idx<<"]: " << percpop[idx]
             <<  " string: " << probe
             << ", largest:" << largest << endl;
        
*/
        cout << "Generation : " << counter 
             << ", Fitness : " << largest << ", string: " << population[idx]
             << " (population["<<idx<<"])" << endl;

        if (largest >= 1.0) break;
    }
    if (counter < 2000)
    {
        cout << "Fitness of 1 was reached at generation : " 
             << counter <<  endl;
    }
    else
    {
        cout << "A Fitness of 1 was within " << MAX_LOOP
             << " loops never reached!\n";
    }
}
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