Merge pull request #148 from SaintDako/master

add matrix.mapMulti
numbers · Jun 13, 2015 · 9a4226f · 9a4226f
2 parents 72b913a + fab14f2
commit 9a4226f
Show file tree

Hide file tree

Showing 2 changed files with 73 additions and 7 deletions.
diff --git a/lib/numbers/matrix.js b/lib/numbers/matrix.js
@@ -1301,15 +1301,48 @@ matrix.isStrictlyColumnDD = function (M) {
 matrix.map = function (M, f) {
   // M is n-by-m (n rows, m columns)
   var n = M.length,
-      m = M[0].length,
-      i, j;
+    m = M[0].length,
+    i, j;
 
   var res = matrix.deepCopy(M);
 
-  for (i=0; i<n; i++) {
-    for (j=0; j<m; j++) {
+  for (i = 0; i < n; i++) {
+    for (j = 0; j < m; j++) {
       res[i][j] = f(M[i][j]);
     }
   }
   return res;
-}
+};
+
+/**
+ * Applies a function to every element of a vector or matrix (i.e. map).
+ * Identical to matrix.map, except that the function passed can take an
+ * arbitrary number of parameters (minimum of 1). Any extra arguments
+ * passed will be * passed to the apply-er function.
+ *
+ * @param {Array} matrix
+ * @param {Function} function to apply to each element
+ * @return {Array} matrix operated on
+ */
+matrix.mapMulti = function (M, f) {
+  // convert arguments object to an array, ignoring M and f
+  // extraArgs is of the form [x, arg0, arg1, ...]
+  var extraArgs = new Array(Object.keys(arguments).length - 1);
+  for (var k = 1; k < extraArgs.length; k++) {
+    extraArgs[k] = arguments[k + 1];
+  }
+
+  var n = M.length,
+    m = M[0].length,
+    i, j;
+
+  var res = matrix.deepCopy(M);
+
+  for (i = 0; i < n; i++) {
+    for (j = 0; j < m; j++) {
+      extraArgs[0] = M[i][j];
+      res[i][j] = f.apply(null, extraArgs);
+    }
+  }
+  return res;
+};
diff --git a/test/matrix.test.js b/test/matrix.test.js
@@ -926,9 +926,9 @@ suite('numbers', function () {
       [2, 3],
       [11, -1]
     ];
-    var addOne = function(x) {
+    var addOne = function (x) {
       return x + 1;
-    }
+    };
 
     var expected1 = [
       [0, 1, 6],
@@ -949,4 +949,37 @@ suite('numbers', function () {
     done();
   });
 
+  test('should test for applying a function to each element of a matrix with addition parameters', function (done) {
+    var m1 = [
+      [1, 3, 5],
+      [-1, -7, 2],
+      [5, 5, 4]
+    ];
+    var m2 = [
+      [-10, 3],
+      [4, 9],
+      [100, 0]
+    ];
+    var scaleAndAddOne = function (x, alpha) {
+      return alpha * x + 1;
+    };
+
+    var expected1 = [
+      [3, 7, 11],
+      [-1, -13, 5],
+      [11, 11, 9]
+    ];
+    var expected2 = [
+      [-29, 10],
+      [13, 28],
+      [301, 1]
+    ];
+
+    var res1 = matrix.mapMulti(m1, scaleAndAddOne, 2);
+    var res2 = matrix.mapMulti(m2, scaleAndAddOne, 3);
+
+    assert.deepEqual(res1, expected1);
+    assert.deepEqual(res2, expected2);
+    done();
+  });
 });