Update 02_math_recap_linear_algebra.ipynb

iacopomasi · Mar 7, 2024 · 9f62ebf · 9f62ebf
1 parent c39ffaa
commit 9f62ebf
Showing 1 changed file with 27 additions and 16 deletions.
diff --git a/AA2324/course/02_math_recap_linear_algebra/02_math_recap_linear_algebra.ipynb b/AA2324/course/02_math_recap_linear_algebra/02_math_recap_linear_algebra.ipynb
@@ -133,7 +133,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 65,
+   "execution_count": 1,
    "metadata": {
     "slideshow": {
      "slide_type": "subslide"
@@ -148,7 +148,7 @@
       " [ 0.   1. ]\n",
       " [ 2.  -3. ]]\n",
       "Shape (3, 2)\n",
-      "Number of dimensions: 2\n",
+      "Number of dimension: 2\n",
       "Number of elements: 6\n"
      ]
     }
@@ -449,7 +449,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 68,
+   "execution_count": 3,
    "metadata": {
     "slideshow": {
      "slide_type": "subslide"
@@ -462,7 +462,7 @@
        "True"
       ]
      },
-     "execution_count": 68,
+     "execution_count": 3,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -661,7 +661,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 73,
+   "execution_count": 5,
    "metadata": {
     "slideshow": {
      "slide_type": "subslide"
@@ -697,7 +697,7 @@
        "True"
       ]
      },
-     "execution_count": 73,
+     "execution_count": 5,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -741,28 +741,38 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 74,
+   "execution_count": 11,
    "metadata": {
     "slideshow": {
      "slide_type": "subslide"
     }
    },
    "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[[0 1 2]\n",
+      " [3 4 5]\n",
+      " [6 7 8]]\n"
+     ]
+    },
     {
      "data": {
       "text/plain": [
-       "array([ 3, 12, 21])"
+       "36"
       ]
      },
-     "execution_count": 74,
+     "execution_count": 11,
      "metadata": {},
      "output_type": "execute_result"
     }
    ],
    "source": [
     "# Sum all the values across cols (cols will disappear)\n",
     "# Sum all values across axis 1.\n",
-    "A.sum(axis=1, keepdims=False) #3 (cols are cancelled out)"
+    "print(A)\n",
+    "A.sum(axis=(0,1), keepdims=False) #3 (cols are cancelled out)"
    ]
   },
   {
@@ -858,7 +868,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 76,
+   "execution_count": 13,
    "metadata": {
     "slideshow": {
      "slide_type": "subslide"
@@ -871,7 +881,7 @@
        "True"
       ]
      },
-     "execution_count": 76,
+     "execution_count": 13,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -1361,7 +1371,7 @@
    "source": [
     "# Einsum = Einstein summation\n",
     "\n",
-    "A is $i\\times k$ and B is $k \\times =j$.\n",
+    "A is $i\\times k$ and B is $k \\times j$.\n",
     "\n",
     "$$ (A\\cdot B)_{ij} = \\sum_{k=1}^K A_{ik}\\cdot B_{kj}$$\n",
     "\n",
@@ -1445,7 +1455,7 @@
     "\n",
     "Einsum way:\n",
     "```python\n",
-    "C = np.einsum('ik,kj -> ij')\n",
+    "C = np.einsum('ik,kj -> ij', A, B)\n",
     "```\n",
     "\n",
     "The usual way seems shorter."
@@ -1536,11 +1546,12 @@
     }
    ],
    "source": [
+    "A = np.array([0, 1, 2]) #1x3   3x4\n",
     "B = np.array([[ 0,  1,  2,  3],  # 0\n",
     "              [ 4,  5,  6,  7],  # 1\n",
     "              [ 8,  9, 10, 11]]) # 2\n",
     "A[:, np.newaxis] * B # we wanna do this np.newaxis is broad cast and tells \n",
-    "                     # numpy to put A as col vector"
+    "                     # numpy to put A as col vector "
    ]
   },
   {
@@ -1698,7 +1709,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 85,
+   "execution_count": 16,
    "metadata": {
     "slideshow": {
      "slide_type": "subslide"