feat(matrices): add outerProduct for vec 2/3/4

thi-ng · May 5, 2019 · 2a9d076 · 2a9d076
1 parent 3134ce6
commit 2a9d076
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diff --git a/packages/matrices/src/index.ts b/packages/matrices/src/index.ts
@@ -28,6 +28,7 @@ export * from "./mulq";
 export * from "./mulv";
 export * from "./normal-mat";
 export * from "./ortho";
+export * from "./outer-product";
 export * from "./perspective";
 export * from "./project";
 export * from "./quat-axis-angle";

diff --git a/packages/matrices/src/outer-product.ts b/packages/matrices/src/outer-product.ts
@@ -0,0 +1,63 @@
+import {
+    MultiVecOpVV,
+    ReadonlyVec,
+    setC,
+    setC4,
+    vop
+} from "@thi.ng/vectors";
+import { Mat } from "./api";
+
+/**
+ * Computes outer/tensor product of vectors `u` and `v`. Returns square
+ * matrix of same dimensions as vectors, e.g. 3x3 matrix for 3D vectors.
+ *
+ * https://en.wikipedia.org/wiki/Outer_product
+ */
+export const outerProduct: MultiVecOpVV = vop(1);
+
+export const outerProduct2 = outerProduct.add(
+    2,
+    (out: Mat, [ux, uy]: ReadonlyVec, [vx, vy]: ReadonlyVec) =>
+        setC4(out || [], ux * vx, uy * vx, ux * vy, uy * vy)
+);
+
+export const outerProduct3 = outerProduct.add(
+    3,
+    (out: Mat, [ux, uy, uz]: ReadonlyVec, [vx, vy, vz]: ReadonlyVec) =>
+        setC(
+            out || [],
+            ux * vx,
+            uy * vx,
+            uz * vx,
+            ux * vy,
+            uy * vy,
+            uz * vy,
+            ux * vz,
+            uy * vz,
+            uz * vz
+        )
+);
+
+export const outerProduct4 = outerProduct.add(
+    4,
+    (out: Mat, [ux, uy, uz, uw]: ReadonlyVec, [vx, vy, vz, vw]: ReadonlyVec) =>
+        setC(
+            out || [],
+            ux * vx,
+            uy * vx,
+            uz * vx,
+            uw * vx,
+            ux * vy,
+            uy * vy,
+            uz * vy,
+            uw * vy,
+            ux * vz,
+            uy * vz,
+            uz * vz,
+            uw * vz,
+            ux * vw,
+            uy * vw,
+            uz * vw,
+            uw * vw
+        )
+);