Fix matrix of matrices

Author: dvd101x

examples/browser/rocket_trajectory_optimization.html

@@ -151,8 +151,8 @@ <h1>Rocket trajectory optimization</h1>
       label: resultName.slice(7),
       data: sim.evaluate(
         'concat('
-        + `(${resultName}[:,4] - phi0) * r0 / rad / km,`  // Surface distance from start (in km)
-        + `(${resultName}[:,1] - r0) / km`                // Height above surface (in km)
+        + `(${resultName}[:,[4]] - phi0) * r0 / rad / km,`  // Surface distance from start (in km)
+        + `(${resultName}[:,[1]] - r0) / km`                // Height above surface (in km)
         + ')'
       ).toArray().map(([x, y]) => ({ x, y })),
       borderColor: i % 2 ? '#999' : '#dc3912',
@@ -171,9 +171,10 @@ <h1>Rocket trajectory optimization</h1>
         .toArray()
         .map(([v, t]) => ({ x: t.toNumber('s'), y: v.toNumber('m/s') }))
     }])
+    console.log(sim.evaluate("result[:,[6]]"))
     createChart([{
       label: 'height (in km)',
-      data: sim.evaluate("concat((result[:, 1] - r0), result[:, 6])")
+      data: sim.evaluate("concat((result[:,[1]] - r0) / km, result[:,[6]])")
         .toArray()
         .map(([r, t]) => ({ x: t.toNumber('s'), y: r.toNumber('km') })),
     }])
@@ -185,7 +186,7 @@ <h1>Rocket trajectory optimization</h1>
     }])
     createChart([{
       label: 'acceleration (in m/s^2)',
-      data: sim.evaluate("concat(diff(result[:, 2]) ./ diff(result[:, 6]), result[:end-1, 6])")
+      data: sim.evaluate("concat(diff(result[:, [2]]) ./ diff(result[:, [6]]), result[:end-1, [6]])")
         .toArray()
         .map(([acc, t]) => ({ x: t.toNumber('s'), y: acc.toNumber('m/s^2') })),
     }])

src/type/matrix/DenseMatrix.js

@@ -573,7 +573,7 @@ export const createDenseMatrixClass = /* #__PURE__ */ factory(name, dependencies
     const result = me.create(undefined, me._datatype)
     result._size = me._size
     if (isUnary || fastCallback.isUnary) {
-      result._data = iterateUnary(me._data)
+      result._data = preprocess(iterateUnary(me._data))
       return result
     }
     if (maxDepth === 0) {
@@ -582,12 +582,12 @@ export const createDenseMatrixClass = /* #__PURE__ */ factory(name, dependencies
       for (let i = 0; i < inputData.length; i++) {
         data[i] = fastCallbackFn(inputData[i], [i], me)
       }
-      result._data = data
+      result._data = preprocess(data)
       return result
     }
 
     const index = []
-    result._data = iterate(me._data)
+    result._data = preprocess(iterate(me._data))
     return result
 
     function iterate (data, depth = 0) {

test/unit-tests/type/matrix/DenseMatrix.test.js

@@ -724,6 +724,12 @@ describe('DenseMatrix', function () {
       assert.deepStrictEqual(m2.valueOf(), [2, 4, 6])
     })
 
+    it('should return a matrix (not a matrix of matrices) when the result of map is a matrix.', function () {
+      const m = new DenseMatrix([[1, 2]])
+      const m2 = m.map(function (value) { return new DenseMatrix([value, value]) })
+      assert.deepStrictEqual(m2.valueOf(), [[[1, 1], [2, 2]]])
+    })
+
     it('should work on empty matrices', function () {
       const m = new DenseMatrix([])
       const m2 = m.map(function (value) { return value * 2 })