fix immunized

AllenDowney · May 28, 2024 · dd98689 · dd98689
1 parent a6d6980
commit dd98689
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Showing 2 changed files with 12 additions and 4 deletions.
diff --git a/chapters/chap12.ipynb b/chapters/chap12.ipynb
@@ -123,8 +123,12 @@
    "outputs": [],
    "source": [
     "def add_immunization(system, fraction):\n",
-    "    system.init.s -= fraction\n",
-    "    system.init.r += fraction"
+    "    # Multiply 'fraction' by the proportion of susceptible\n",
+    "    # individual to be sure to subtract and add a value that \n",
+    "    # does not exceeds the proportion of susceptible \n",
+    "    # individials\n",
+    "    system.init.s -= fraction*system.init.s\n",
+    "    system.init.r += fraction*system.init.s"
    ]
   },
   {

diff --git a/notebooks/chap12.ipynb b/notebooks/chap12.ipynb
@@ -243,8 +243,12 @@
     "    system: System object\n",
     "    fraction: number from 0 to 1\n",
     "    \"\"\"\n",
-    "    system.init.S -= fraction\n",
-    "    system.init.R += fraction"
+    "    # Multiply 'fraction' by the proportion of susceptible\n",
+    "    # individual to be sure to subtract and add a value that \n",
+    "    # does not exceeds the proportion of susceptible \n",
+    "    # individials\n",
+    "    system.init.S -= fraction*system.init.S\n",
+    "    system.init.R += fraction*system.init.S"
    ]
   },
   {