# PyTorch adds torch::stable::add to stable ABI

> **Key takeaway:** PyTorch introduces a stable addition operator to support the torchvision stable-ABI port.

**Published:** 2026-10-16T13:49:08+00:00 
**Source:** PyTorch GitHub Releases 
**Category:** bigtech-foss 
**Canonical URL:** https://fosswire.org/news/pytorch-adds-torchstableadd-to-stable-abi.html 

## Summary
PyTorch has added the torch::stable::add operator to its stable Application Binary Interface (ABI), gated by the TORCH_VERSION_2_16_0 flag. This change provides a standardized way to perform tensor addition, which is required for the torchvision stable-ABI port to function without workarounds. The new operator mirrors the existing torch::stable::subtract functionality.

## Technical details of the addition operator
- Implements `torch::stable::add(self, other, double alpha = 1.0)` using the aten C shim `aoti_torch_aten_add_Tensor`.
- Uses a `double` for the `alpha` parameter instead of a `Scalar` due to C shim lowering.
- Adding two integral or boolean tensors is rejected by aten, though mixed integral/floating point inputs work via type promotion.
- Includes a new `libtorch_agn_2_16` extension and updated documentation for stable operators.

## Why it matters
This update enables the torchvision stable-ABI port to operate more cleanly by removing the need for subtraction-based workarounds.