Read-only array exchange via the buffer protocol #217
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This PR adapts nanobind so that it can both receive and return arrays representing read-only memory. This is communicated via the standard ``const`` type modifier, e.g. by replacing ``nb::ndarray<float, ...>`` with ``nb::ndarray<const float, ...>``. The PR also adapts accessors (``data()``, ``operator()``) so that they only return constant references/pointers in that case. The change is for now specific to the buffer protocol used to exchange data with NumPy. The DLPack interface (with PyTorch, Tensorflow, etc.) ignores the read-only annotation. This may change at some point in the future when an upcoming DLPack version with a read-only bit is more widely deployed.
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This PR adapts nanobind so that it can both receive and return arrays representing read-only memory. This is communicated via the standard
consttype modifier, e.g. by replacingnb::ndarray<float, ...>withnb::ndarray<const float, ...>.The PR also adapts accessors (
data(),operator()) so that they only return constant references/pointers in that case.The change is for now specific to the buffer protocol used to exchange nd-arrays with NumPy. The DLPack interface (used to exchange nd-arrays with PyTorch, Tensorflow, etc.) ignores the read-only annotation. This may change at some point in the future when an upcoming DLPack version with a read-only bit is more widely deployed.
This PR only targets the
ndarrayclass. It will be nice to also propagate it into the Eigen type caster (@WKarel ?)