package numbercruncher.mathutils;

/**
 * The base class for differential equation solvers.
 */
public abstract class DiffEqSolver {
  /** the differential equation to solve */
  protected DifferentialEquation equation;

  /** the initial condition data point */
  protected DataPoint initialCondition;

  /** current x value */
  protected float x;
  /** current y value */
  protected float y;

  /**
   * Constructor.
   * @param equation the differential equation to solve
   */
  public DiffEqSolver(DifferentialEquation equation) {
    this.equation = equation;
    this.initialCondition = equation.getInitialCondition();

    reset();
  }

  /**
   * Reset x and y to the initial condition data point.
   */
  public void reset() {
    this.x = initialCondition.x;
    this.y = initialCondition.y;
  }

  /**
   * Return the next data point in the
   * approximation of the solution.
   * @param h the width of the interval
   */
  public abstract DataPoint nextPoint(float h);
}