166 lines
4.4 KiB
C++
166 lines
4.4 KiB
C++
// model with logistic population growth & basic
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// inflation + estate redistribution systems
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#include <iostream>
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#include <vector>
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#include <map>
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#include <cmath>
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#include <cstdlib>
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#include <algorithm>
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#include "econ.hpp"
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#include "io.hpp"
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#include "util.hpp"
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std::map<std::string, std::string> config;
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#define c(a) config[a]
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#define ci(a) std::stoi(config[a])
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#define cf(a) std::stof(config[a])
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#define csets(k, v) config[k] = v
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#define csetn(k, v) config[k] = std::to_string(v);
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std::vector<int> ages;
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std::vector<int> balances;
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enum estate_mode {
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EVEN_REDIST,
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INHERITANCE
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};
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// used by kill_even_redist
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int redist_total = 0;
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int redist_total_next = 0;
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// pop modeling functions
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/**
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* @brief kill participant of ID and redistribute their wealth
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* to all other remaining participants evenly
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*
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* @param id ID of participant to kill
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*/
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void kill_even_redist(int id) {
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int bal = balances.at(id);
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ages.erase(ages.begin()+id);
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balances.erase(balances.begin()+id);
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redist_total_next += bal;
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}
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/**
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* @brief kill participant of ID and give it to one random
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* participant as inheritance
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*
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* @param id ID of participant to kill
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*/
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void kill_inheritance(int id) {
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int bal = balances.at(id);
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ages.erase(ages.begin()+id);
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balances.erase(balances.begin()+id);
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int recipient_id = random_item(balances, true);
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balances.at(recipient_id) += bal;
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}
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/**
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* @brief Age all participants by 1 year & kill any that are
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* over the age limit
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*
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* @param mode Redistribution mode
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*/
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void age_all(estate_mode mode) {
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for (int i = 0; i < ages.size(); i++) {
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ages.at(i) += 1;
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if (ages.at(i) > ci("MAX_AGE")) {
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switch (mode) {
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case INHERITANCE:
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kill_inheritance(i);
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break;
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case EVEN_REDIST:
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kill_even_redist(i);
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break;
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}
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}
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}
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}
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int logistic_population_func(int year) {
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// https://en.wikipedia.org//wiki/Logistic_function
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return ci("N_o") + (ci("N_f") - ci("N_o")) /
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(1 + exp(-cf("GROWTH_RATE") * (year - ci("DURATION")/2)));
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}
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void adjust_population(int year) {
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int diff = logistic_population_func(year) - balances.size();
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if (diff > 0) {
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for (int i = 0; i < diff; i++) {
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ages.push_back(1);
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balances.push_back(ci("STARTING_BALANCE_NEW"));
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}
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}
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}
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int main() {
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// set config - make configurable with params later
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// model params
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csetn("DURATION", 1000);
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csetn("MAX_AGE", 81);
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csetn("INIT_BALANCE_EACH", 5000);
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csetn("STARTING_BALANCE_NEW", 1000); // effectively inflation rate
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// logistic growth params
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csetn("N_o", 10);
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csetn("N_f", 10000);
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csetn("GROWTH_RATE", 0.04);
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// init state
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ages.assign(ci("N_o"), 1);
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balances.assign(ci("N_o"), ci("INIT_BALANCE_EACH"));
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// estate mode
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// estate_mode emode = INHERITANCE;
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estate_mode emode = EVEN_REDIST;
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for (int year = 0; year < ci("DURATION"); year++) {
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// std::cout << year << "\t" << balances.size() << std::endl;
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age_all(emode);
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adjust_population(year);
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for (int j = 0; j < balances.size(); j++) {
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// redistribute estates
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balances.at(j) += redist_total / balances.size();
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// make 3 arbitrary spending decisions -> 30% of savings
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for (int k = 0; k < 3; k++) {
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economic_decision_simple(balances, j, 0.1);
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}
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}
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if (year % 100 == 0) {
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int avg = 0;
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int avg_age = 0;
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for (int i = 0; i < balances.size(); i++) {
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avg += balances[i];
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}
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for (int i = 0; i < balances.size(); i++) {
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avg_age += ages[i];
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}
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avg /= balances.size();
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avg_age /= ages.size();
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std::cout << std::endl;
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std::cout << "year: " << year << std::endl;
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std::cout << "avg bal: " << avg << std::endl;
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std::cout << "avg age: " << avg_age << std::endl;
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std::cout << "players: " << balances.size() << std::endl;
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}
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// reset redist tally
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redist_total = redist_total_next;
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redist_total_next = 0;
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}
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// std::sort(balances.begin(), balances.end(), std::greater<int>());
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dump_balances_and_ages_csv(balances, ages, "pop-balances-out");
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std::cout << "Finished with " << balances.size() << " balances\n";
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return 0;
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}
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