Files
@ 4493466dd03d
Branch filter:
Location: AENC/switchchain/powerlaw_info.tex - annotation
4493466dd03d
1.2 KiB
text/x-tex
Add canonical timeevol mathematica file
42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d 42dadc398e7d | \documentclass{article}
\begin{document}
\section{Continuous powerlaw with minimum cut-off}
Exponent $\tau > 1$.
\subsection{Also maximum cut-off}
Let $m$ be the minimum, $M$ be the maximum.\\
PDF: $$f(x) = \frac{\tau-1}{m^{-(\tau-1)} - M^{-(\tau-1)}} x^{-\tau}$$
CDF: $$F(x) = \frac{m^{-(\tau-1)} - x^{-(\tau-1)}}{m^{-(\tau-1)} - M^{-(\tau-1)}}$$
Inverse: $$F^{-1}(y) = \left( (1-y) m^{-(\tau-1)} + y M^{-(\tau-1)} \right)^{\frac{-1}{\tau-1}}$$
i.e. linear interpolate between $M^{-(\tau-1)} < m^{-(\tau-1)}$.\\
$F^{-1}(0) = m$ and $F^{-1}(1) = M$.\\
For $m=1$ and $M$ steps of interpolation:\\
$F^{-1}(1/M) = \left( 1-M^{-1} + M^{-\tau} \right)^{\frac{-1}{\tau-1}}$\\
$F^{-1}(1-1/M) = \left( M^{-1} + M^{-(\tau-1)} - M^{-\tau} \right)^{\frac{-1}{\tau-1}}$
\subsection{No maximum cut-off}
For $M=\infty$ we have:\\
PDF: $$f(x) = \frac{\tau-1}{m^{-(\tau-1)}} x^{-\tau} = \frac{\tau-1}{m} \left(\frac{x}{m}\right)^{-\tau}$$
CDF: $$F(x) = \frac{m^{-(\tau-1)} - x^{-(\tau-1)}}{m^{-(\tau-1)}} = 1 - \left(\frac{x}{m}\right)^{-(\tau-1)}$$
Inverse: $$F^{-1}(y) = \left( (1-y) m^{-(\tau-1)} \right)^{\frac{-1}{\tau-1}} = m \; \left( 1-y \right)^{\frac{-1}{\tau-1}}$$
For interpolation:\\
$F^{-1}(0) = m$\\
$F^{-1}(1-\frac{1}{n}) = m\cdot n^{\frac{1}{\tau-1}}$
\end{document}
|