[RFC PATCH v2 09/12] ipa: libipa: vector: Add sum() function

[Milan Zamazal]

Laurent Pinchart <laurent.pinchart at ideasonboard.com> writes:

> Add a function to calculate the sum of a vector. It will be useful for
> algorithms.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

Reviewed-by: Milan Zamazal <mzamazal at redhat.com>

> ---
> Changes since v1:
>
> - Drop Vector::normalize()
> ---
>  src/ipa/libipa/vector.cpp | 12 ++++++++++++
>  src/ipa/libipa/vector.h   |  7 +++++++
>  2 files changed, 19 insertions(+)
>
> diff --git a/src/ipa/libipa/vector.cpp b/src/ipa/libipa/vector.cpp
> index 14816cdb5d09..19e7537f8a5a 100644
> --- a/src/ipa/libipa/vector.cpp
> +++ b/src/ipa/libipa/vector.cpp
> @@ -296,6 +296,18 @@ namespace ipa {
>   * \return The length of the vector
>   */
>  
> +/**
> + * \fn Vector::sum() const
> + * \brief Calculate the sum of all the vector elements
> + * \tparam R The type of the sum
> + *
> + * The type R of the sum defaults to the type T of the elements, but can be set
> + * explicitly to use a different type in case the type T would risk
> + * overflowing.
> + *
> + * \return The sum of all the vector elements
> + */
> +
>  /**
>   * \fn Vector<T, Rows> operator*(const Matrix<T, Rows, Cols> &m, const Vector<T, Cols> &v)
>   * \brief Multiply a matrix by a vector
> diff --git a/src/ipa/libipa/vector.h b/src/ipa/libipa/vector.h
> index 949dc4650aa4..f55da6476103 100644
> --- a/src/ipa/libipa/vector.h
> +++ b/src/ipa/libipa/vector.h
> @@ -9,6 +9,7 @@
>  #include <algorithm>
>  #include <array>
>  #include <cmath>
> +#include <numeric>
>  #include <optional>
>  #include <ostream>
>  
> @@ -245,6 +246,12 @@ public:
>  		return std::sqrt(length2());
>  	}
>  
> +	template<typename R = T>
> +	constexpr R sum() const
> +	{
> +		return std::accumulate(data_.begin(), data_.end(), R{});
> +	}
> +
>  private:
>  	static constexpr Vector apply(const Vector &lhs, const Vector &rhs, std::function<T(T, T)> func)
>  	{