48 lines
1.4 KiB
C++
48 lines
1.4 KiB
C++
#include <iostream>
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#include <iomanip>
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using namespace std;
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// Iterations for Euler's method
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const int DAYS = 200, ITER = 10000;
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// Population size
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const int POP = 10000;
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// Model parameters
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// Beta = infection rate
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// Gamma = removal rate
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const double beta = 0.3944, gamma = 0.02664;
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// Compartments
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double S[DAYS + 1], I[DAYS + 1], R[DAYS + 1];
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int main() {
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// Initial conditions
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S[0] = 1 - 1.0 / POP, I[0] = 1.0 / POP, R[0] = 0;
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// Run simulation
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for (int i = 0; i < DAYS; ++i) {
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double S_[ITER + 1], I_[ITER + 1], R_[ITER + 1];
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S_[0] = S[i], I_[0] = I[i], R_[0] = R[i];
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// Euler's method
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for (int j = 0; j < ITER; ++j) {
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S_[j+1] = S_[j] + (-beta * S_[j] * I_[j]) / ITER;
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I_[j+1] = I_[j] + (beta * S_[j] * I_[j] - gamma * I_[j]) / ITER;
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R_[j+1] = R_[j] + (gamma * I_[j]) / ITER;
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}
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S[i + 1] = S_[ITER], I[i + 1] = I_[ITER], R[i + 1] = R_[ITER];
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}
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// Print results
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cout << "| DAY | SUSCEPTIBLE | INFECTIOUS | RECOVERED |\n";
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cout << "-------------------------------------------------\n";
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for (int i = 0; i < DAYS; ++i) {
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cout << "| " << setw(3) << i << " | "; // Day
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cout << setw(11) << (int)(POP * S[i] + .5) << " | "; // Suspectible
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cout << setw(11) << (int)(POP * I[i] + .5) << " | "; // Infectious
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cout << setw(11) << (int)(POP * R[i] + .5) << " |\n"; // Recovered
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}
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} |