feat(vectors): add generic strided dot product

- add `dotS()` for arbitrary sized strided vectors
thi-ng · Aug 29, 2021 · 9c34793 · 9c34793
1 parent 2bbb54e
commit 9c34793
Showing 1 changed file with 15 additions and 1 deletion.
diff --git a/packages/vectors/src/dots.ts b/packages/vectors/src/dots.ts
@@ -1,7 +1,21 @@
-import type { VecOpSRoVV } from "./api";
+import type { ReadonlyVec, VecOpSRoVV } from "./api";
 import { compile, SARGS_V } from "./internal/codegen";
 import { DOT } from "./internal/templates";
 
+export const dotS = (
+    a: ReadonlyVec,
+    b: ReadonlyVec,
+    n: number,
+    ia = 0,
+    ib = 0,
+    sa = 1,
+    sb = 1
+) => {
+    let sum = 0;
+    for (; --n >= 0; ia += sa, ib += sb) sum += a[ia] * b[ib];
+    return sum;
+};
+
 const $ = (dim: number): VecOpSRoVV<number> =>
     compile(dim, DOT, `o,a,${SARGS_V}`, "o,a", "", "+", "return ", ";", true);