Example usage for org.apache.commons.math3.ode FirstOrderIntegrator addEventHandler

Introduction

In this page you can find the example usage for org.apache.commons.math3.ode FirstOrderIntegrator addEventHandler.

Prototype

void addEventHandler(EventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount);

Source Link

Document

Add an event handler to the integrator.

Usage

From source file:de.uni_erlangen.lstm.modelaccess.Model.java

/**
 * Run the model using set parameters//from   w w w. j a  v a  2  s.co m
 */
public void simulate() {
    finished = false;
    /*
     * Integrator selection 
     */
    //FirstOrderIntegrator integrator = new HighamHall54Integrator(1.0e-8, 100.0, 1.0e-10, 1.0e-10);
    //FirstOrderIntegrator integrator = new DormandPrince54Integrator(1.0e-12, 100.0, 1.0e-12, 1.0e-12);
    //FirstOrderIntegrator integrator = new DormandPrince853Integrator(1.0e-8, 100.0, 1.0e-10, 1.0e-10);
    //FirstOrderIntegrator integrator = new GraggBulirschStoerIntegrator(1.0e-8, 100.0, 1.0e-10, 1.0e-10);
    FirstOrderIntegrator integrator = new AdamsBashforthIntegrator(2, 1.0e-14, 100.0, 1.0e-10, 1.0e-10);
    //FirstOrderIntegrator integrator = new AdamsMoultonIntegrator(2, 1.0e-8, 100.0, 1.0e-10, 1.0e-10);

    // influent values, digester parameters, S_H_ion, dae system
    final DAEModel ode = new DAEModel(u, param, S_H_ion, dae, fix_pH);
    //FirstOrderDifferentialEquations ode = model; 

    // Records progress
    StepHandler progHandler = new StepHandler() {
        public void init(double t0, double[] y0, double t) {
        }

        public void handleStep(StepInterpolator interpolator, boolean isLast) {
            progress = interpolator.getCurrentTime();
        }
    };
    integrator.addStepHandler(progHandler);

    /*
     * Continuous model recorded in CSV
     */
    if (onlineRecord) {
        final CSVWriter writer = new CSVWriter();
        StepHandler stepHandler = new StepHandler() {
            double prevT = 0.0;

            public void init(double t0, double[] y0, double t) {
            }

            public void handleStep(StepInterpolator interpolator, boolean isLast) {
                double t = interpolator.getCurrentTime();
                if (t - prevT > resolution) {
                    // Add time to the beginning of the array
                    double[] timemodel = new double[ode.getDimensions().length + 1];
                    timemodel[0] = t;

                    // We need to pull variables (S_h2 and acid-base) directly from the model if using DAE
                    for (int i = 1; i < timemodel.length; i++) {
                        timemodel[i] = ode.getDimensions()[i - 1];
                    }

                    writer.WriteArray(output_file, timemodel, true);
                    prevT = t;
                }
            }
        };
        integrator.addStepHandler(stepHandler);
    }

    /*
     * Add event handlers for discrete events
     * maxCheck - maximal time interval between switching function checks (this interval prevents missing sign changes in case the integration steps becomes very large)
      * conv - convergence threshold in the event time search
      * maxIt - upper limit of the iteration count in the event time search
     */
    if (events.size() > 0) {
        for (DiscreteEvent event : events) {
            double maxCheck = Double.POSITIVE_INFINITY;
            double conv = 1.0e-20;
            int maxIt = 100;
            integrator.addEventHandler(event, maxCheck, conv, maxIt);
        }
    }

    integrator.integrate(ode, start, x, end, x);

    /*
     * Return the time that the discrete event occurred
     */
    if (events.size() > 0) {
        for (DiscreteEvent event : events) {
            if (event.getTime() < end) {
                end = event.getTime();
            }
        }
    }

    // We need to pull variables (S_h2 and acid-base) directly from the model
    x = ode.getDimensions();

    finished = true;
}

---