Structured kernels are a new way to write kernels in PyTorch. Why did they take so long? What finally convinced us that we should do them? Why did it end up taking me the better part of a year to only be half done with them?

Further reading:

• Structured kernels RFC https://github.com/pytorch/rfcs/blob/rfc-0005/RFC-0005-structured-kernel-definitions.md
• Taxonomy of PyTorch operators by shape behavior http://blog.ezyang.com/2020/05/a-brief-taxonomy-of-pytorch-operators-by-shape-behavior/
• Bram Wasti's lazy tensor prototype https://github.com/pytorch/pytorch/pull/25753