OpenMP truncating float

Question

I am reading a data (1-dimensional/vector) from a CSV file into a float array and applying Quick Sort on it:

int main()
{

float floatArr[2000];

ReadRandomData(floatArr, "D:\RandomData.csv");

//#pragma omp parallel
{
    QuickSort(floatArr, 0,2000);
}

for(int i=0; i<2000; i++)
{
    cout<<floatArr[i]<<endl;
}

_getch();

}

and output is something like this:

but once I uncomment the #pragma omp parallel part, output is something like this (its truncating I think):

Can anyone explain me why is this happening with OpenMP and how to fix it? Thanks in advance!

UPDATE

Here is QuickSort part:

void QuickSort(float* arr, int startIndex, int endIndex)
{
    int pivot = arr[startIndex];                    //pivot element is the leftmost element
    int splitPoint;

if(endIndex > startIndex)                        //if they are equal, it means there is only one element and quicksort's job here is finished
{
    splitPoint = Splitarr(arr, pivot, startIndex, endIndex);
                                                  //Splitarr() returns the position where pivot belongs to
    arr[splitPoint] = pivot;
    QuickSort(arr, startIndex, splitPoint-1);   //Quick sort first half
    QuickSort(arr, splitPoint+1, endIndex);  //Quick sort second half
}

}

and here is Splitting Code:

int Splitarr(float* arr, int pivot, int startIndex, int endIndex)
{
    int leftBoundary = startIndex;
    int rightBoundary = endIndex;

while(leftBoundary < rightBoundary)            //shuttle pivot until the boundaries meet
{
     while( pivot < arr[rightBoundary]        //keep moving until a lesser element is found
            && rightBoundary > leftBoundary)      //or until the leftBoundary is reached
     {
          rightBoundary--;                      //move left
     }

            swap(arr[leftBoundary], arr[rightBoundary]);


     while( pivot >= arr[leftBoundary]        //keep moving until a greater or equal element is found
            && leftBoundary < rightBoundary)      //or until the rightBoundary is reached
     {
          leftBoundary++;                        //move right
     }

            swap(arr[rightBoundary], arr[leftBoundary]);

}

return rightBoundary;                             //leftBoundary is the split point because
                                                  //the above while loop exits only when 
                                                  //leftBoundary and rightBoundary are equal
}

Answer 1

There is one thing in your algorithm which I assume is causing the problem.

Change line:

int pivot = arr[startIndex];

to

float pivot = arr[startIndex];

Converting float to int truncates the decimals, as you correctly presumed. That might solve your issue.