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Adding world population transition notebook
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‎code/examples/world_pop_transition.ipynb‎

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{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# Modeling and Simulation in Python\n",
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"\n",
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"Project 1 example\n",
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"\n",
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"Copyright 2018 Allen Downey\n",
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"\n",
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"License: [Creative Commons Attribution 4.0 International](https://creativecommons.org/licenses/by/4.0)\n"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"# Configure Jupyter so figures appear in the notebook\n",
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"%matplotlib inline\n",
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"\n",
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"# Configure Jupyter to display the assigned value after an assignment\n",
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"%config InteractiveShell.ast_node_interactivity='last_expr_or_assign'\n",
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"\n",
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"# import functions from the modsim library\n",
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"from modsim import *"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"from pandas import read_html\n",
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"\n",
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"filename = 'data/World_population_estimates.html'\n",
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"tables = read_html(filename, header=0, index_col=0, decimal='M')\n",
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"table2 = tables[2]\n",
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"table2.columns = ['census', 'prb', 'un', 'maddison', \n",
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" 'hyde', 'tanton', 'biraben', 'mj', \n",
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" 'thomlinson', 'durand', 'clark']"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"def plot_results(census, un, timeseries, title):\n",
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" \"\"\"Plot the estimates and the model.\n",
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" \n",
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" census: TimeSeries of population estimates\n",
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" un: TimeSeries of population estimates\n",
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" timeseries: TimeSeries of simulation results\n",
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" title: string\n",
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" \"\"\"\n",
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" plot(census, ':', label='US Census')\n",
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" plot(un, '--', label='UN DESA')\n",
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" if len(timeseries):\n",
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" plot(timeseries, color='gray', label='model')\n",
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" \n",
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" decorate(xlabel='Year', \n",
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" ylabel='World population (billion)',\n",
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" title=title)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"un = table2.un / 1e9\n",
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"census = table2.census / 1e9\n",
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"empty = TimeSeries()\n",
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"plot_results(census, un, empty, 'World population estimates')"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"half = get_first_value(census) / 2"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"init = State(young=half, old=half)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"system = System(birth_rate1 = 1/18,\n",
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" birth_rate2 = 1/25,\n",
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" mature_rate = 1/40,\n",
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" death_rate = 1/40,\n",
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" t_0 = 1950,\n",
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" t_end = 2016,\n",
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" transition_year = 1970,\n",
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" init=init)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"def update_func1(state, t, system):\n",
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" births = system.birth_rate1 * state.young\n",
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" \n",
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" maturings = system.mature_rate * state.young\n",
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" deaths = system.death_rate * state.old\n",
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" \n",
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" young = state.young + births - maturings\n",
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" old = state.old + maturings - deaths\n",
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" \n",
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" return State(young=young, old=old)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"state = update_func1(init, system.t_0, system)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"state = update_func1(state, system.t_0, system)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"def run_simulation(system, update_func):\n",
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" \"\"\"Simulate the system using any update function.\n",
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" \n",
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" init: initial State object\n",
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" system: System object\n",
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" update_func: function that computes the population next year\n",
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" \n",
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" returns: TimeSeries\n",
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" \"\"\"\n",
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" results = TimeSeries()\n",
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" \n",
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" state = system.init\n",
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" results[system.t_0] = state.young + state.old\n",
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" \n",
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" for t in linrange(system.t_0, system.t_end):\n",
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" state = update_func(state, t, system)\n",
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" results[t+1] = state.young + state.old\n",
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" \n",
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" return results"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"results = run_simulation(system, update_func1);"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"plot_results(census, un, results, 'World population estimates')"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": []
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": []
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.6.6"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 2
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}

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