thrust::max_element

Defined in thrust/extrema.h

template<typename DerivedPolicy, typename ForwardIterator, typename BinaryPredicate> ForwardIterator thrust::max_element(const thrust::detail::execution_policy_base<DerivedPolicy> &exec, ForwardIterator first, ForwardIterator last, BinaryPredicate comp)

max_element finds the largest element in the range [first, last). It returns the first iterator i in [first, last) such that no other iterator in [first, last) points to a value larger than *i. The return value is last if and only if [first, last) is an empty range.

The two versions of max_element differ in how they define whether one element is less than another. This version compares objects using a function object comp. Specifically, this version of max_element returns the first iterator i in [first, last) such that, for every iterator j in [first, last), comp(*i, *j) is false.

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

The following code snippet demonstrates how to use max_element to find the largest element of a collection of key-value pairs using the thrust::host execution policy for parallelization.

#include <thrust/extrema.h>
#include <thrust/execution_policy.h>
...

struct key_value
{
  int key;
  int value;
};

struct compare_key_value
{
  __host__ __device__
  bool operator()(key_value lhs, key_value rhs)
  {
    return lhs.key < rhs.key;
  }
};

...
key_value data[4] = { {4,5}, {0,7}, {2,3}, {6,1} };

key_value *largest = thrust::max_element(thrust::host, data, data + 4, compare_key_value());

// largest == data + 3
// *largest == {6,1}