thrust::binary_search

Defined in thrust/binary_search.h

template<typename DerivedPolicy, typename ForwardIterator, typename T, typename StrictWeakOrdering> bool thrust::binary_search(const thrust::detail::execution_policy_base<DerivedPolicy> &exec, ForwardIterator first, ForwardIterator last, const T &value, StrictWeakOrdering comp)

binary_search is a version of binary search: it attempts to find the element value in an ordered range [first, last). It returns true if an element that is equivalent to value is present in [first, last) and false if no such element exists. Specifically, this version returns true if and only if there exists an iterator i in [first, last) such that comp(*i, value) and comp(value, *i) are both false.

The algorithm’s execution is parallelized as determined by exec.

The following code snippet demonstrates how to use binary_search to search for values in a ordered range using the thrust::device execution policy for parallelization:

#include <thrust/binary_search.h>
#include <thrust/device_vector.h>
#include <thrust/functional.h>
#include <thrust/execution_policy.h>
...
thrust::device_vector<int> input(5);

input[0] = 0;
input[1] = 2;
input[2] = 5;
input[3] = 7;
input[4] = 8;

thrust::binary_search(thrust::device, input.begin(), input.end(), 0, thrust::less<int>()); // returns true
thrust::binary_search(thrust::device, input.begin(), input.end(), 1, thrust::less<int>()); // returns false
thrust::binary_search(thrust::device, input.begin(), input.end(), 2, thrust::less<int>()); // returns true
thrust::binary_search(thrust::device, input.begin(), input.end(), 3, thrust::less<int>()); // returns false
thrust::binary_search(thrust::device, input.begin(), input.end(), 8, thrust::less<int>()); // returns true
thrust::binary_search(thrust::device, input.begin(), input.end(), 9, thrust::less<int>()); // returns false

See also

lower_bound

See also

upper_bound

See also

equal_range

Parameters

exec – The execution policy to use for parallelization.
first – The beginning of the ordered sequence.
last – The end of the ordered sequence.
value – The value to be searched.
comp – The comparison operator.

Template Parameters

DerivedPolicy – The name of the derived execution policy.
ForwardIterator – is a model of Forward Iterator.
T – is comparable to ForwardIterator's value_type.
StrictWeakOrdering – is a model of Strict Weak Ordering.

Returns

true if an equivalent element exists in [first, last), otherwise false.