main.js

/**
 * Right-hand side of our ODE written as a system of first-order ODEs.
 *
 * @param objectOfInputs An object containing all the problem parameters.
 * @param t              Time (seconds).
 * @param vars           An array of dependent variables.
 * @return               An array of derivatives.
 */
function f(objectOfInputs, t, vars, dt) {
    var [S, I, R] = vars;
    var { beta, gamma, delta } = objectOfInputs;
    // Determine N
    var N = S + I + R;
    // Calculate derivatives
    var dSdt = - beta * S * I * (1 - delta) / N;
    var dIdt = beta * S * I * (1 - delta) / N - gamma * I;
    var dRdt = gamma * I;
    // Put into return value
    return [dt * dSdt, dt * dIdt, dt * dRdt];
}

/**
 * Generates a 3D phase plot
 * 
 * @param solution       An object containing solution data. 
 * @return               Nothing.
 */
function generateSIRPhasePlot(solution) {
    // Extract solution data
    var { vars } = solution;
    var [S, I, R] = vars;

    // Generate 3D plot
    gen3DPlot(S, I, R, "phasePlotSIR", "Phase plot of the solution to the SIR equations.", { xtitle: "Susceptible", ytitle: "Infectious", ztitle: "Recovered" });
}

/**
 * Generates a SI phase plot
 * 
 * @param solution       An object containing solution data. 
 * @return               Nothing.
 */
function generateSIPhasePlot(solution) {
    // Extract solution data
    var { vars } = solution;
    var S = vars[0];
    var I = vars[1];

    // Generate 2D plot
    gen2DPlot(S, I, "phasePlotSI", "Infectious vs susceptible phase plot", "Susceptible", "Infectious")
}

/**
 * Generates a SR phase plot
 * 
 * @param solution       An object containing solution data.
 * @return               Nothing.
 */
function generateSRPhasePlot(solution) {
    // Extract solution data
    var { vars } = solution;
    var S = vars[0];
    var R = vars[2];

    // Generate 2D plot
    gen2DPlot(S, R, "phasePlotSR", "Recovered vs susceptible phase plot", "Susceptible", "Recovered");
}

/**
 * Generates a IR phase plot
 * 
 * @param solution       An object containing solution data. 
 * @return               Nothing.
 */
function generateIRPhasePlot(solution) {
    // Extract solution data
    var { vars } = solution;
    var I = vars[1];
    var R = vars[2];

    // Generate 2D plot
    gen2DPlot(I, R, "phasePlotIR", "Recovered vs infectious phase plot", "Infectious", "Recovered");
}

/**
 * Generates a time plot
 * 
 * @param solution       An object containing solution data. 
 * @return               Nothing.
 */
function generateTimePlot(solution) {
    // Generate time plot
    genMultPlot(solution, ["Susceptible", "Infectious", "Recovered"], "timePlot", "Plot of SIR against time");
}

/**
 * Generate five plots:
 * - The first is a 3D phase plot of S, I and R.
 * - The second is a 2D phase plot of I against S.
 * - The third is a 2D phase plot of R against S.
 * - The fourth is a 2D phase plot of R against I.
 * - The fifth is a plot of S, I and R against time.
 * 
 * @param objectOfInputs An object containing all the form parameters. 
 * @return               Nothing. Just generates the plots.
 */
function generatePlots(objectOfInputs = undefined, solution = undefined) {
    if (objectOfInputs == undefined) {
        var objectOfInputs = readInputs();
    }
    if (solution == undefined) {
        var solution = solveProblem(RKF45, objectOfInputs);
    }

    // Generate plots
    generateSIRPhasePlot(solution);
    generateSRPhasePlot(solution);
    generateSRPhasePlot(solution);
    generateIRPhasePlot(solution);
    generateTimePlot(solution);
};

/**
 * Generate animation
 * @return nothing. 
 */
function generateAnimation(objectOfInputs = undefined, solution = undefined) {
    if (objectOfInputs == undefined) {
        var objectOfInputs = readInputs();
    }
    if (solution == undefined) {
        var solution = solveProblem(RKF45, objectOfInputs);
    }
    animate3D(solution, { varnames: ["Susceptible", "Infectious", "Recovered"], title: "Susceptible, infectious and recovered population phase plot for the SIR infectious disease model." });
}

function generateTable(objectOfInputs = undefined, solution = undefined) {
    if (objectOfInputs == undefined) {
        var objectOfInputs = readInputs();
    }
    if (solution == undefined) {
        var solution = solveProblem(RKF45, objectOfInputs);
    }
    fillTable(objectOfInputs, ['Susceptible', 'Infectious', 'Recovered'], solution)
}

function generateTable(objectOfInputs = undefined, solution = undefined) {
    fillTable(objectOfInputs, ['Susceptible', 'Infectious', 'Recovered'], solution)
}