relife.renewal_process.renewal_equation_solver

relife.renewal_process.renewal_equation_solver

relife.renewal_process.renewal_equation_solver(F: numpy.ndarray, Fm: numpy.ndarray, y: numpy.ndarray, D: Optional[numpy.ndarray] = None) numpy.ndarray[source]

Renewal equation solver.

Parameters
  • F (ndarray) – The cumulative distribution function evaluated at each point of the timeline.

  • Fm (ndarray) – The cumulative distribution function evaluated at each midpoint of the timeline.

  • y (ndarray) – A given function evaluated at each point of the timeline.

  • D (ndarray, optional) – Discount function value at each point of the timeline, by default None.

Returns

Renewal function evaluated at each point of the timeline.

Return type

ndarray

Notes

The timeline must start at 0.

Solve the renewal equation for \(z\), such that for \(t\geq 0\).

\[\begin{split}\begin{aligned} z(t) & = y(t) + \int_0^t z(t-x) D(x) \mathrm{d}F(x) \\ & = y(t) + z \ast F(t) \end{aligned}\end{split}\]

where \(F\) is the cumulative distribution function, \(y\) a function and \(D\) the exponential discounting factor.

References

1

Dragomir, S. S. (2011). Approximating the Riemann–Stieltjes integral by a trapezoidal quadrature rule with applications. Mathematical and computer modelling, 54(1-2), 243-260.

2

Tortorella, M. (2005). Numerical solutions of renewal-type integral equations. INFORMS Journal on Computing, 17(1), 66-74.