Implement pythonstl.numeric module

[AnshMNSoni]

Problem

The library has no numeric module. C++ <numeric> provides essential mathematical range operations that are widely used in algorithms and data processing, none of which are currently available in PythonSTL.

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Proposed Module: pythonstl.numeric

Function	C++ Equivalent	Description
accumulate(arr, init)	std::accumulate	Sum/fold over a range with initial value
inner_product(a, b, init)	std::inner_product	Dot product of two ranges
partial_sum(arr)	std::partial_sum	Prefix sum array
adjacent_difference(arr)	std::adjacent_difference	Differences between consecutive elements
iota(arr, start)	std::iota	Fills array with incrementing values from start
gcd(a, b)	std::gcd (C++17)	Greatest common divisor
lcm(a, b)	std::lcm (C++17)	Least common multiple
reduce(arr, init)	std::reduce (C++17)	Like accumulate but order-independent
exclusive_scan(arr, init)	std::exclusive_scan (C++17)	Prefix sum excluding current element
inclusive_scan(arr)	std::inclusive_scan (C++17)	Prefix sum including current element

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Expected API

from pythonstl.numeric import accumulate, partial_sum, iota, gcd, lcm

arr = [1, 2, 3, 4, 5]
print(accumulate(arr, 0))       # 15
print(partial_sum(arr))         # [1, 3, 6, 10, 15]

buf = [0] * 5
iota(buf, 1)
print(buf)                      # [1, 2, 3, 4, 5]

print(gcd(12, 8))               # 4
print(lcm(4, 6))                # 12

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Checklist

• accumulate
• inner_product
• partial_sum
• adjacent_difference
• iota
• gcd, lcm
• reduce
• exclusive_scan, inclusive_scan
• Unit tests for all functions
• Docstrings with O() complexity

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Notes

• accumulate, partial_sum, iota, gcd, and lcm are the highest priority as they are most commonly used.
• C++17 additions (reduce, exclusive_scan, inclusive_scan) can be implemented in a later phase.