Package org.rrd4j.data

Class CubicSplineInterpolator

java.lang.Object
org.rrd4j.data.Plottable
org.rrd4j.data.CubicSplineInterpolator
All Implemented Interfaces:
IPlottable
public class CubicSplineInterpolator extends Plottable
Class used to interpolate datasource values from the collection of (timestamp, values) points using natural cubic spline interpolation.

WARNING: So far, this class cannot handle NaN datasource values (an exception will be thrown by the constructor). Future releases might change this.

  • Constructor Summary

    Constructors
    Constructor
    Description
    CubicSplineInterpolator(double[] x, double[] y)
    Creates cubic spline interpolator for an array of 2D-points.
    CubicSplineInterpolator(long[] timestamps, double[] values)
    Creates cubic spline interpolator from arrays of timestamps and corresponding datasource values.
    CubicSplineInterpolator(Calendar[] dates, double[] values)
    Creates cubic spline interpolator from arrays of GregorianCalendar objects and corresponding datasource values.
    CubicSplineInterpolator(Date[] dates, double[] values)
    Creates cubic spline interpolator from arrays of Date objects and corresponding datasource values.

  • Method Summary

    Modifier and Type
    Method
    Description
    double
    getValue(double xval)
    Calculates spline-interpolated y-value for the corresponding x-value.
    double
    getValue(long timestamp)
    Retrieves datapoint value based on a given timestamp.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • CubicSplineInterpolator

      public CubicSplineInterpolator(long[] timestamps, double[] values)
      Creates cubic spline interpolator from arrays of timestamps and corresponding datasource values.
      Parameters:
      timestamps - timestamps in seconds
      values - corresponding datasource values
      Throws:
      IllegalArgumentException - Thrown if supplied arrays do not contain at least 3 values, or if timestamps are not ordered, or array lengths are not equal, or some datasource value is NaN.

    • CubicSplineInterpolator

      public CubicSplineInterpolator(Date[] dates, double[] values)
      Creates cubic spline interpolator from arrays of Date objects and corresponding datasource values.
      Parameters:
      dates - Array of Date objects
      values - corresponding datasource values
      Throws:
      IllegalArgumentException - Thrown if supplied arrays do not contain at least 3 values, or if timestamps are not ordered, or array lengths are not equal, or some datasource value is NaN.

    • CubicSplineInterpolator

      public CubicSplineInterpolator(Calendar[] dates, double[] values)
      Creates cubic spline interpolator from arrays of GregorianCalendar objects and corresponding datasource values.
      Parameters:
      dates - Array of GregorianCalendar objects
      values - corresponding datasource values
      Throws:
      IllegalArgumentException - Thrown if supplied arrays do not contain at least 3 values, or if timestamps are not ordered, or array lengths are not equal, or some datasource value is NaN.

    • CubicSplineInterpolator

      public CubicSplineInterpolator(double[] x, double[] y)
      Creates cubic spline interpolator for an array of 2D-points.
      Parameters:
      x - x-axis point coordinates
      y - y-axis point coordinates
      Throws:
      IllegalArgumentException - Thrown if supplied arrays do not contain at least 3 values, or if timestamps are not ordered, or array lengths are not equal, or some datasource value is NaN.

  • Method Details

    • getValue

      public double getValue(double xval)
      Calculates spline-interpolated y-value for the corresponding x-value. Call this if you need spline-interpolated values in your code.
      Parameters:
      xval - x-value
      Returns:
      inteprolated y-value

    • getValue

      public double getValue(long timestamp)
      Retrieves datapoint value based on a given timestamp. Use this method if you only have one series of data in this class. Method overridden from the base class. This method will be called by the framework. Call this method only if you need spline-interpolated values in your code.
      Specified by:
      getValue in interface IPlottable
      Specified by:
      getValue in class Plottable
      Parameters:
      timestamp - Timestamp in seconds for the datapoint.
      Returns:
      Double value of the datapoint.