Strides

Developer notes for include/stratax/core/Strides.hpp.

Purpose

Stores row-major stride values derived from a Shape.

Main API

Constructors

• Default constructor
• Strides(shape)

Metadata

• size()
• rank()
• empty()

Element Access

• operator()(dimension_index)
• at(dimension_index)
• front()
• back()
• data()

Iteration and Utilities

• begin() / end()
• cbegin() / cend()
• rbegin() / rend()
• operator==
• operator!=
• swap()
• operator<<

Invariants

• rank() always equals the number of stored stride values.
• Strides generated from a shape have the same rank as that shape.
• For non-empty shapes, the last stride is 1.
• Strides are row-major.
• Empty shapes produce empty strides.
• Public iteration exposes read-only stride values.

Validation Notes

• at() checks bounds through core::validation::require_index().
• operator() is unchecked.
• Empty shapes produce empty strides.
• Stride multiplication uses core::validation::checked_multiply() and throws Exceptions::DimensionError.

Implementation Notes

• For shape (2, 3, 4), strides are (12, 4, 1).
• Tensor multi-index access depends on these values.
• Public stride indexing should use operator().
• Iteration exposes read-only stride values.
• Keep stride overflow and bounds checks routed through Validation.hpp.
• operator<< is inline because this file is header-only.

Time Complexity

• Default construction, size(), rank(), empty(), element access, front(), back(), data(), iterator access, and swap() are O(1).
• Construction from Shape is O(r), where r is rank.
• Equality, inequality, and stream output are O(r).

Future Work

• Add column-major or layout policy support.
• Consider explicit layout metadata if multiple memory orders are added.