Re: Efficient Vector Comparison

user923005 <dcorbit@xxxxxxxxx> writes:

On Jun 28, 1:48 am, Yao Qi <qiyao...@xxxxxxxxx> wrote:
In our program, we will compare every two vectors. In current
implementation, we compare every element of that vector until we get
the
comparison result. It is not any more efficient way to do this?

b.t.w the length of vector is variable.

Do you have to sort the vectors?

Yeah, what I want is to sort the vectors. Unfortunately, our code base
is written in C, and we use a dynamic array to represent a vector.
After profiling, I find that the vector comparison is not so efficient.



Why not something simple like:

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

int main(void)
{
vector < double > a;
vector < double > b;
a.resize(100);
b.resize(100);
size_t index;
for (index = 0; index < 100; index++)
{
a[index] = (double)index;
b[index] = (double) index;
if (index == 99) b[index]+=1.0;
}
if (a < b)
cout << "a is less than b" << endl;
else if (a > b)
cout << "a is greater than b" << endl;
else
cout << "a is equal to b" << endl;
return 0;
}



Best Regards

--
Yao Qi <qiyaoltc@xxxxxxxxx> GNU/Linux Developer
http://duewayqi.googlepages.com/

Live within your income, even if you have to borrow to do so.
-- Josh Billings
.

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