thrust::inner_product

Defined in thrust/inner_product.h

template<typename DerivedPolicy, typename InputIterator1, typename InputIterator2, typename OutputType> OutputType thrust::inner_product(const thrust::detail::execution_policy_base<DerivedPolicy> &exec, InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, OutputType init)

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

Specifically, this version of inner_product computes the sum init + (*first1 * *first2) + (*(first1+1) * *(first2+1)) + ...

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

The following code demonstrates how to use inner_product to compute the dot product of two vectors using the thrust::host execution policy for parallelization.

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

float result = thrust::inner_product(thrust::host, vec1, vec1 + 3, vec2, 0.0f);

// result == 31.0f