thrust::inner_product

Defined in thrust/inner_product.h

template<typename InputIterator1, typename InputIterator2, typename OutputType, typename BinaryFunction1, typename BinaryFunction2>
OutputType thrust::inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, OutputType init, BinaryFunction1 binary_op1, BinaryFunction2 binary_op2)

inner_product calculates an inner product of the ranges [first1, last1) and [first2, first2 + (last1 - first1)).

This version of inner_product is identical to the first, except that is uses two user-supplied function objects instead of operator+ and operator*.

Specifically, this version of inner_product computes the sum binary_op1( init, binary_op2(*first1, *first2) ), ...

Unlike the C++ Standard Template Library function std::inner_product, this version offers no guarantee on order of execution.

#include <thrust/inner_product.h>
...
float vec1[3] = {1.0f, 2.0f, 5.0f};
float vec2[3] = {4.0f, 1.0f, 5.0f};

float init = 0.0f;
thrust::plus<float>       binary_op1;
thrust::multiplies<float> binary_op2;

float result = thrust::inner_product(vec1, vec1 + 3, vec2, init, binary_op1, binary_op2);

// result == 31.0f

See also

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

Parameters

  • first1 – The beginning of the first sequence.

  • last1 – The end of the first sequence.

  • first2 – The beginning of the second sequence.

  • init – Initial value of the result.

  • binary_op1 – Generalized addition operation.

  • binary_op2 – Generalized multiplication operation.

Template Parameters

  • InputIterator1 – is a model of Input Iterator, and InputIterator1's value_type is convertible to BinaryFunction2's first argument type.

  • InputIterator2 – is a model of Input Iterator. and InputIterator2's value_type is convertible to BinaryFunction2's second argument type.

  • OutputType – is a model of Assignable, and OutputType is convertible to BinaryFunction1's first argument type.

  • BinaryFunction1 – The function’s return type must be convertible to OutputType.

  • BinaryFunction2 – The function’s return type must be convertible to BinaryFunction1's second argument type.

Returns

The inner product of sequences [first1, last1) and [first2, last2).