max_element#

Overloads#

max_element(exec, first, last)#

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

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 greater than another. This version compares objects using operator<. Specifically, this version of max_element returns the first iterator i in [first, last) such that, for every iterator j in [first, last), *i < *j is false.

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

#include <thrust/extrema.h>
#include <thrust/execution_policy.h>
...
int data[6] = {1, 0, 2, 2, 1, 3};
int *result = thrust::max_element(thrust::host, data, data + 6);

// *result == 3

See also

https://en.cppreference.com/w/cpp/algorithm/max_element

Parameters:

  • exec – The execution policy to use for parallelization.

  • first – The beginning of the sequence.

  • last – The end of the sequence.

Template Parameters:
Returns:

An iterator pointing to the largest element of the range [first, last), if it is not an empty range; last, otherwise.

max_element(first, last)#

template<typename ForwardIterator>
ForwardIterator thrust::max_element(
ForwardIterator first,
ForwardIterator last,
)#

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 greater than another. This version compares objects using operator<. Specifically, this version of max_element returns the first iterator i in [first, last) such that, for every iterator j in [first, last), *i < *j is false.

#include <thrust/extrema.h>
...
int data[6] = {1, 0, 2, 2, 1, 3};
int *result = thrust::max_element(data, data + 6);

// *result == 3

See also

https://en.cppreference.com/w/cpp/algorithm/max_element

Parameters:

  • first – The beginning of the sequence.

  • last – The end of the sequence.

Template Parameters:

ForwardIterator – is a model of Forward Iterator, and ForwardIterator's value_type is a model of LessThan Comparable.

Returns:

An iterator pointing to the largest element of the range [first, last), if it is not an empty range; last, otherwise.

max_element(exec, first, last, comp)#

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}

See also

https://en.cppreference.com/w/cpp/algorithm/max_element

Parameters:

  • exec – The execution policy to use for parallelization.

  • first – The beginning of the sequence.

  • last – The end of the sequence.

  • comp – A binary predicate used for comparison.

Template Parameters:

  • DerivedPolicy – The name of the derived execution policy.

  • ForwardIterator – is a model of Forward Iterator, and ForwardIterator's value_type is convertible to both comp's first and second argument type.

  • BinaryPredicate – is a model of Binary Predicate.

Returns:

An iterator pointing to the largest element of the range [first, last), if it is not an empty range; last, otherwise.

max_element(first, last, comp)#

template<typename ForwardIterator, typename BinaryPredicate>
ForwardIterator thrust::max_element(
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 following code snippet demonstrates how to use max_element to find the largest element of a collection of key-value pairs.

#include <thrust/extrema.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(data, data + 4, compare_key_value());

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

See also

https://en.cppreference.com/w/cpp/algorithm/max_element

Parameters:

  • first – The beginning of the sequence.

  • last – The end of the sequence.

  • comp – A binary predicate used for comparison.

Template Parameters:

  • ForwardIterator – is a model of Forward Iterator, and ForwardIterator's value_type is convertible to both comp's first and second argument type.

  • BinaryPredicate – is a model of Binary Predicate.

Returns:

An iterator pointing to the largest element of the range [first, last), if it is not an empty range; last, otherwise.