update week6 exercise

Author: ougx

week6_exercise.ipynb

@@ -4,14 +4,18 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "### 1. Given two 1-d arrays of simulated values and observed values, Write a Pyhton function to calculate the mean error, coefficient of determination and nash coefficient. Not allowed to use loops."
+    "### 1. Given two 1-d arrays of simulated values and observed values, Write a Pyhton function \n",
+    "\n",
+    "### to calculate the mean error, coefficient of determination and nash coefficient. Loops are NOT allowed."
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "### 2. Given `x` and `y`, write a Python function to perform linear regression which returns `a`, `c` and `sum of square errors` where `ax + c = y` \n",
+    "### 2. Given `x` and `y`, write a Python function to perform linear regression \n",
+    "\n",
+    "### which returns `a`, `c` and `sum of square errors` where `ax + c = y` \n",
     "```python\n",
     "def linear_regression(x, y):\n",
     "    \n",
@@ -26,11 +30,11 @@
     "### 3. Eestimate the mean precipitation on different land use types.\n",
     "\n",
     "```python\n",
-    "landuse       = np.random.randint(1, 5, [5, 5])\n",
-    "precipitation = np.random.random([5, 5])\n",
+    "landuse = np.random.randint(1, 5, [5, 5])\n",
+    "precip  = np.random.random([5, 5])\n",
     "\n",
     "print('landuse\\n', landuse)\n",
-    "print('landuse\\n', precipitation)\n",
+    "print('precip \\n', precip)\n",
     "```\n",
     "\n"
    ]
@@ -39,7 +43,17 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "### 4. We have two array. The first array is the distribution of irrigated land. The second array is the precipitation. \n",
+    "### 4. We have two array. The first array is the distribution of irrigated land. \n",
+    "\n",
+    "### The second array is the precipitation. \n",
+    "\n",
+    "```python\n",
+    "landuse = np.random.randint(0, 1, [6, 6])\n",
+    "precip  = np.random.random([6, 6])\n",
+    "\n",
+    "print('landuse\\n', landuse)\n",
+    "print('precip \\n', precip)\n",
+    "```\n",
     "\n",
     "A. Create a function to create the buffer zones of varied distances to the irrigated land.\n",
     "\n",
@@ -50,7 +64,10 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "### 5. Write a Python function to find the nearest point of a list of given points. You are not allowed to use any type of loops.\n",
+    "### 5. Write a Python function to find the nearest point of a list of given points. \n",
+    "\n",
+    "### You are not allowed to use any type of loops.\n",
+    "\n",
     "e. g. points = [(3, 4), (1, 2), (7, 8), (9, 4), (6, 5), (8, 7), (4, 7)]\n",
     "\n",
     "Hint: using numpy to create a N x N array which contain the distances between each ith an jth point pair; where N is the numer of points."