程序包 org.hipparchus.ode

类 FirstOrderConverter

java.lang.Object
org.hipparchus.ode.FirstOrderConverter
所有已实现的接口:
OrdinaryDifferentialEquation
public class FirstOrderConverter extends Object implements OrdinaryDifferentialEquation
This class converts second order differential equations to first order ones.

This class is a wrapper around a SecondOrderODE which allow to use a ODEIntegrator to integrate it.

The transformation is done by changing the n dimension state vector to a 2n dimension vector, where the first n components are the initial state variables and the n last components are their first time derivative. The first time derivative of this state vector then really contains both the first and second time derivative of the initial state vector, which can be handled by the underlying second order equations set.

One should be aware that the data is duplicated during the transformation process and that for each call to computeDerivatives, this wrapper does copy 4n scalars : 2n before the call to computeSecondDerivatives in order to dispatch the y state vector into z and zDot, and 2n after the call to gather zDot and zDDot into yDot. Since the underlying problem by itself perhaps also needs to copy data and dispatch the arrays into domain objects, this has an impact on both memory and CPU usage. The only way to avoid this duplication is to perform the transformation at the problem level, i.e. to implement the problem as a first order one and then avoid using this class.

另请参阅:

  • 构造器详细资料

    • FirstOrderConverter

      public FirstOrderConverter(SecondOrderODE equations)
      简单构造函数。围绕二阶方程集构建一个转换器。
      参数:
      equations - 要转换的二阶方程集

  • 方法详细资料

    • getDimension

      public int getDimension()
      获取问题的维度。

      一阶问题的维度是基础二阶问题的两倍。

      指定者:
      getDimension 在接口中 OrdinaryDifferentialEquation
      返回:
      问题的维度

    • computeDerivatives

      public double[] computeDerivatives(double t, double[] y)
      获取状态向量的当前时间导数。
      指定者:
      computeDerivatives 在接口中 OrdinaryDifferentialEquation
      参数:
      t - 独立时间变量的当前值
      y - 包含状态向量当前值的数组
      返回:
      状态向量的时间导数