[Mlir-commits] [mlir] [MLIR][Linalg][Docs] Add forms to Linalg rationale docs (PR #156859)

[Andrzej Warzyński]

================
@@ -506,6 +506,58 @@ potential by introducing lower-level IR ops and *smaller* Linalg ops.
 This gradually reduces the potential, all the way to Loops + VectorOps
 and LLVMIR.
 
+### Interchangeability of Forms<a name="forms"></a>
+
+#### The Linalg Forms
+
+The core Linalg operation tree has three forms:
+* **Generic:** Represented by `linalg.generic` and can encode all perfectly-nested
+loop operations.
+* **Category:** Represented by `linalg.contract` and `linalg.elementwise`,
+which are special (einsum) forms of the `generic` operation. In the future, other
----------------
banach-space wrote:

I would a reference documenting `einsum` (there was a time when the term was very not obvious to me)
```suggestion
which are special ((einsum_[https://rockt.ai/2018/04/30/einsum]) forms of the `generic` operation. In the future, other
```

https://github.com/llvm/llvm-project/pull/156859