[system-a] tensor/ -- extract Link

Author: xieyuheng

src/system-a/tensor/Link.ts

@@ -0,0 +1,21 @@
+import {
+  gradientStateGetWithDefault,
+  gradientStateSet,
+  type GradientState,
+} from "../gradient-descent/index.js"
+import { type Scalar } from "./Scalar.js"
+
+export type Link = (
+  y: Scalar,
+  accumulator: number,
+  state: GradientState,
+) => GradientState
+
+export function endOfChain(
+  d: Scalar,
+  z: number,
+  state: GradientState,
+): GradientState {
+  const g = gradientStateGetWithDefault(state, d, 0)
+  return gradientStateSet(state, d, z + g)
+}

src/system-a/tensor/Scalar.ts

@@ -1,8 +1,4 @@
-import {
-  gradientStateGetWithDefault,
-  gradientStateSet,
-  type GradientState,
-} from "../gradient-descent/index.js"
+import { endOfChain, type Link } from "./Link.js"
 
 export type Dual = { "@type": "Dual"; real: number; link: Link }
 
@@ -39,18 +35,3 @@ export function scalarLink(x: Scalar): Link {
 export function scalarTruncate(x: Scalar): Scalar {
   return Dual(scalarReal(x), endOfChain)
 }
-
-export type Link = (
-  y: Scalar,
-  accumulator: number,
-  state: GradientState,
-) => GradientState
-
-export function endOfChain(
-  d: Scalar,
-  z: number,
-  state: GradientState,
-): GradientState {
-  const g = gradientStateGetWithDefault(state, d, 0)
-  return gradientStateSet(state, d, z + g)
-}

src/system-a/tensor/index.ts

@@ -1,3 +1,4 @@
+export * from "./Link.js"
 export * from "./Scalar.js"
 export * from "./Tensor.js"
 export * from "./assertions.js"