[PATCH v3 06/17] ipa: libipa: vector: Generalize arithmetic operators

[Laurent Pinchart]

Hi Barnabás,

On Mon, Nov 18, 2024 at 11:40:16PM +0000, Barnabás Pőcze wrote:
> 2024. november 18., hétfő 23:16 keltezéssel, Laurent Pinchart írta:
> 
> > Instead of hand-coding all arithmetic operators, implement them based on
> > a generic apply() function that takes an operator-specific
> > std::function. This will simplify adding missing arithmetic operators.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > Reviewed-by: Milan Zamazal <mzamazal at redhat.com>
> > ---
> > Changes since v2:
> > 
> > - Include <algorithm>
> > - Use std::plus, std::minus, std::multiplies and std::divides
> > ---
> >  src/ipa/libipa/vector.h | 50 ++++++++++++++++++++++++-----------------
> >  1 file changed, 30 insertions(+), 20 deletions(-)
> > 
> > diff --git a/src/ipa/libipa/vector.h b/src/ipa/libipa/vector.h
> > index 2abb5536361c..76fd2934b870 100644
> > --- a/src/ipa/libipa/vector.h
> > +++ b/src/ipa/libipa/vector.h
> > @@ -6,8 +6,10 @@
> >   */
> >  #pragma once
> > 
> > +#include <algorithm>
> >  #include <array>
> >  #include <cmath>
> > +#include <functional>
> >  #include <optional>
> >  #include <ostream>
> > 
> > @@ -78,36 +80,24 @@ public:
> >  		return ret;
> >  	}
> > 
> > -	constexpr Vector<T, Rows> operator-(const Vector<T, Rows> &other) const
> > +	constexpr Vector operator-(const Vector &other) const
> >  	{
> > -		Vector<T, Rows> ret;
> > -		for (unsigned int i = 0; i < Rows; i++)
> > -			ret[i] = data_[i] - other[i];
> > -		return ret;
> > +		return apply(*this, other, std::minus<>{});
> >  	}
> > 
> > -	constexpr Vector<T, Rows> operator+(const Vector<T, Rows> &other) const
> > +	constexpr Vector operator+(const Vector &other) const
> >  	{
> > -		Vector<T, Rows> ret;
> > -		for (unsigned int i = 0; i < Rows; i++)
> > -			ret[i] = data_[i] + other[i];
> > -		return ret;
> > +		return apply(*this, other, std::plus<>{});
> >  	}
> > 
> > -	constexpr Vector<T, Rows> operator*(T factor) const
> > +	constexpr Vector operator*(T factor) const
> >  	{
> > -		Vector<T, Rows> ret;
> > -		for (unsigned int i = 0; i < Rows; i++)
> > -			ret[i] = data_[i] * factor;
> > -		return ret;
> > +		return apply(*this, factor, std::multiplies<>{});
> >  	}
> > 
> > -	constexpr Vector<T, Rows> operator/(T factor) const
> > +	constexpr Vector operator/(T factor) const
> >  	{
> > -		Vector<T, Rows> ret;
> > -		for (unsigned int i = 0; i < Rows; i++)
> > -			ret[i] = data_[i] / factor;
> > -		return ret;
> > +		return apply(*this, factor, std::divides<>{});
> >  	}
> > 
> >  	constexpr T dot(const Vector<T, Rows> &other) const
> > @@ -182,6 +172,26 @@ public:
> >  	}
> > 
> >  private:
> > +	static constexpr Vector apply(const Vector &lhs, const Vector &rhs, std::function<T(T, T)> func)
> > +	{
> > +		Vector result;
> > +		std::transform(lhs.data_.begin(), lhs.data_.end(),
> > +			       rhs.data_.begin(), result.data_.begin(),
> > +			       func);
> > +
> > +		return result;
> > +	}
> > +
> > +	static constexpr Vector apply(const Vector &lhs, T rhs, std::function<T(T, T)> func)
> > +	{
> > +		Vector result;
> > +		std::transform(lhs.data_.begin(), lhs.data_.end(),
> > +			       result.data_.begin(),
> > +			       [&func, rhs](T v) { return func(v, rhs); });
> > +
> > +		return result;
> > +	}
> 
> `std::function` is quite heavy. I think making `apply()` a template would be
> beneficial wrt. performance.

I'll try it out in v4.

> > +
> >  	std::array<T, Rows> data_;
> >  };
> > 

-- 
Regards,

Laurent Pinchart