geomspace.hpp

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#pragma once
 
#include "NumCpp/Core/Enums.hpp"
#include "NumCpp/Core/Internal/Error.hpp"
#include "NumCpp/Core/Internal/StaticAsserts.hpp"
#include "NumCpp/Functions/logb.hpp"
#include "NumCpp/Functions/logspace.hpp"
#include "NumCpp/Functions/nth_root.hpp"
#include "NumCpp/NdArray.hpp"
#include "NumCpp/Utils/essentiallyEqual.hpp"
 
namespace nc
{
    //============================================================================
    // Method Description:
    template<typename dtype>
    NdArray<double> geomspace(dtype start, dtype stop, uint32 num = 50, EndPoint endPoint = EndPoint::YES)
    {
        STATIC_ASSERT_ARITHMETIC_OR_COMPLEX(dtype);
 
        if (utils::essentiallyEqual(start, dtype{ 0 }))
        {
            THROW_INVALID_ARGUMENT_ERROR("Geometric sequence cannot include zero");
        }
 
        if (num == 1)
        {
            return { static_cast<double>(start) };
        }
        else if (num == 2 && endPoint == EndPoint::YES)
        {
            return { static_cast<double>(start), static_cast<double>(stop) };
        }
 
        const auto base     = nth_root(stop / start, num - 1);
        const auto logStart = logb(start, base);
        const auto logStop  = logb(stop, base);
        return logspace(logStart, logStop, num, endPoint, base);
    }
} // namespace nc