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Diffstat (limited to 'sir_model.cpp')
| -rw-r--r-- | sir_model.cpp | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/sir_model.cpp b/sir_model.cpp new file mode 100644 index 0000000..f054c36 --- /dev/null +++ b/sir_model.cpp @@ -0,0 +1,48 @@ +#include <iostream> +#include <iomanip> +using namespace std; + +// Iterations for Euler's method +const int DAYS = 200, ITER = 10000; + +// Population size +const int POP = 2000; + +// Model parameters +// Beta = infection rate +// Gamma = removal rate +const double beta = 0.42, gamma = 0.25; + +// Compartments +double S[DAYS + 1], I[DAYS + 1], R[DAYS + 1]; + +int main() { + // Initial conditions + S[0] = 1 - 1.0 / POP, I[0] = 1.0 / POP, R[0] = 0; + + // Run simulation + for (int i = 0; i < DAYS; ++i) { + double S_[ITER + 1], I_[ITER + 1], R_[ITER + 1]; + + S_[0] = S[i], I_[0] = I[i], R_[0] = R[i]; + + // Euler's method + for (int j = 0; j < ITER; ++j) { + S_[j+1] = S_[j] + (-beta * S_[j] * I_[j]) / ITER; + I_[j+1] = I_[j] + (beta * S_[j] * I_[j] - gamma * I_[j]) / ITER; + R_[j+1] = R_[j] + (gamma * I_[j]) / ITER; + } + + S[i + 1] = S_[ITER], I[i + 1] = I_[ITER], R[i + 1] = R_[ITER]; + } + + // Print results + cout << "| DAY | SUSCEPTIBLE | INFECTIOUS | RECOVERED |\n"; + cout << "-------------------------------------------------\n"; + for (int i = 0; i < DAYS; ++i) { + cout << "| " << setw(3) << i << " | "; // Day + cout << setw(11) << (int)(POP * S[i] + .5) << " | "; // Suspectible + cout << setw(11) << (int)(POP * I[i] + .5) << " | "; // Infectious + cout << setw(11) << (int)(POP * R[i] + .5) << " |\n"; // Recovered + } +}
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