Template Function thrust::count(InputIterator, InputIterator, const EqualityComparable&)

Function Documentation

template<typename InputIterator, typename EqualityComparable>
thrust::iterator_traits<InputIterator>::difference_type thrust::count(InputIterator first, InputIterator last, const EqualityComparable &value)

count finds the number of elements in [first,last) that are equal to value. More precisely, count returns the number of iterators i in [first, last) such that *i == value.

The following code snippet demonstrates how to use

count to count the number of instances in a range of a value of interest. 
#include <thrust/count.h>
#include <thrust/device_vector.h>
...
// put 3 1s in a device_vector
thrust::device_vector<int> vec(5,0);
vec[1] = 1;
vec[3] = 1;
vec[4] = 1;

// count the 1s
int result = thrust::count(vec.begin(), vec.end(), 1);
// result == 3
Return

The number of elements equal to value.

Parameters

  • first: The beginning of the sequence.

  • last: The end of the sequence.

  • value: The value to be counted.

Template Parameters

  • InputIterator: must be a model of Input Iterator and InputIterator's value_type must be a model of must be a model of Equality Comparable.

  • EqualityComparable: must be a model of Equality Comparable and can be compared for equality with InputIterator's value_type

See

http://www.sgi.com/tech/stl/count.html