Initial data commit

Task/Kronecker-product/JavaScript/kronecker-product-5.js

@@ -0,0 +1,87 @@
+(() => {
+    'use strict';
+
+    // --------- KRONECKER PRODUCT OF TWO MATRICES ---------
+
+    // kprod :: [[Num]] -> [[Num]] -> [[Num]]
+    const kprod = xs =>
+        ys => concatMap(
+            compose(map(concat), transpose)
+        )(
+            map(map(
+                flip(compose(map, map, mul))(ys)
+            ))(xs)
+        );
+
+    // ----------------------- TEST ------------------------
+    // main :: IO ()
+    const main = () =>
+        unlines(map(compose(unlines, map(show)))([
+            kprod([
+                [1, 2],
+                [3, 4]
+            ])([
+                [0, 5],
+                [6, 7]
+            ]), [], // One empty output line
+            kprod([
+                [0, 1, 0],
+                [1, 1, 1],
+                [0, 1, 0]
+            ])([
+                [1, 1, 1, 1],
+                [1, 0, 0, 1],
+                [1, 1, 1, 1]
+            ])
+        ]));
+
+
+    // ----------------- GENERIC FUNCTIONS -----------------
+
+    // compose (<<<) :: (b -> c) -> (a -> b) -> a -> c
+    const compose = (...fs) =>
+        x => fs.reduceRight((a, f) => f(a), x);
+
+
+    // concat :: [[a]] -> [a]
+    const concat = xs => [].concat.apply([], xs);
+
+
+    // concatMap :: (a -> [b]) -> [a] -> [b]
+    const concatMap = f =>
+        xs => xs.flatMap(f);
+
+
+    // flip :: (a -> b -> c) -> b -> a -> c
+    const flip = f =>
+        x => y => f(y)(x);
+
+
+    // map :: (a -> b) -> [a] -> [b]
+    const map = f =>
+        xs => xs.map(f);
+
+
+    // mul (*) :: Num a => a -> a -> a
+    const mul = a =>
+        b => a * b;
+
+
+    // show :: a -> String
+    const show = x =>
+        JSON.stringify(x); //, null, 2);
+
+
+    // transpose :: [[a]] -> [[a]]
+    const transpose = xs =>
+        xs[0].map((_, col) => xs.map(row => row[col]));
+
+
+    // unlines :: [String] -> String
+    const unlines = xs =>
+        xs.join('\n');
+
+
+    // MAIN ---
+    console.log(main());
+})();