arange.hpp

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#pragma once
 
#include <string>
#include <vector>
 
#include "NumCpp/Core/Internal/Error.hpp"
#include "NumCpp/Core/Internal/StaticAsserts.hpp"
#include "NumCpp/NdArray.hpp"
 
namespace nc
{
    //============================================================================
    // Method Description:
    template<typename dtype>
    NdArray<dtype> arange(dtype inStart, dtype inStop, dtype inStep = 1)
    {
        STATIC_ASSERT_ARITHMETIC(dtype);
 
        if (inStep > 0 && inStop < inStart)
        {
            THROW_INVALID_ARGUMENT_ERROR("stop value must be larger than the start value for positive step.");
        }
 
        if (inStep < 0 && inStop > inStart)
        {
            THROW_INVALID_ARGUMENT_ERROR("start value must be larger than the stop value for negative step.");
        }
 
        std::vector<dtype> values;
 
        dtype theValue = inStart;
        auto  counter  = dtype{ 1 };
 
        if (inStep > 0)
        {
            while (theValue < inStop)
            {
                values.push_back(theValue);
                theValue = inStart + inStep * counter++;
            }
        }
        else
        {
            while (theValue > inStop)
            {
                values.push_back(theValue);
                theValue = inStart + inStep * counter++;
            }
        }
 
        return NdArray<dtype>(values);
    }
 
    //============================================================================
    // Method Description:
    template<typename dtype>
    NdArray<dtype> arange(dtype inStop)
    {
        if (inStop <= 0)
        {
            THROW_INVALID_ARGUMENT_ERROR("stop value must ge greater than 0.");
        }
 
        return arange<dtype>(0, inStop, 1);
    }
 
    //============================================================================
    // Method Description:
    template<typename dtype>
    NdArray<dtype> arange(const Slice& inSlice)
    {
        return arange<dtype>(inSlice.start, inSlice.stop, inSlice.step);
    }
} // namespace nc