LAB3: updated tsp lab to decribe objective function objects.

optimisation/03_routing_and_scheduling_part1.ipynb

@@ -269,7 +269,16 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "# Calculating the length of a tour"
+    "# Calculating the length of a tour\n",
+    "\n",
+    "To calculate the length of a tour you can use either `SimpleTSPObjective` or `OptimisedSimpleTSPObjective`.  For larger problems (e.g. a 70 city) problem you should find that `OptimisedSimpleTSPObjective` offers an efficiency boost (it runs quicker).  But for smaller problems the overhead to set up the optimised approach means that `SimpleTSPObjective` is more efficient!\n",
+    "\n",
+    "The code below illustrates how to create each type of objective and how to use them to cost a tour.  If you are interested try changing the tour size (up to a max of 70) and executing the code.  It will report an average runtime.\n",
+    "\n",
+    "```python\n",
+    "#create a tour with 8 cities.\n",
+    "tour = np.arange(8)\n",
+    "```"
    ]
   },
   {
@@ -278,8 +287,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "objective = SimpleTSPObjective(matrix)\n",
-    "objective.evaluate(tour)"
+    "#create a tour\n",
+    "rng = np.random.default_rng(seed=42)\n",
+    "tour = np.arange(8)\n",
+    "rng.shuffle(tour)\n",
+    "tour"
    ]
   },
   {
@@ -288,10 +300,9 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "rng = np.random.default_rng(seed=42)\n",
-    "tour = np.arange(8)\n",
-    "rng.shuffle(tour)\n",
-    "tour"
+    "#create an instance of an objective object and cost a tour.\n",
+    "objective = SimpleTSPObjective(matrix)\n",
+    "objective.evaluate(tour)"
    ]
   },
   {
@@ -309,10 +320,19 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "#create an instance of an optimised objective function\n",
     "objective2 = OptimisedSimpleTSPObjective(matrix)\n",
     "objective2.evaluate(tour)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The following code run the `evaluate` method multiple times and reports average execution speed.\n",
+    "This will vary by the system you are using and by the size of the problem instance."
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,