slides: write about the Moyal PDF parameters

Also add the Landau, Moyal and 'both' plots.
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Giù Marcer 2020-06-05 23:27:21 +02:00 committed by rnhmjoj
parent de864471e2
commit 95b334322f
4 changed files with 170 additions and 94 deletions

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slides/sections/0.md Normal file
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---
title: Randomness tests of a non-uniform distribution
date: \today
author:
- Giulia Marcer
- Michele Guerini Rocco
institute:
- Università di Milano-Bicocca
theme: metropolis
aspectratio: 169
fontsize: 14pt
mathfont: FiraMath-Regular
sansfont: Fira Sans
header-includes: |
```{=latex}
% Misc
% "thus" in formulas
\DeclareMathOperator{\thus}{%
\hspace{30pt} \Longrightarrow \hspace{30pt}
}
% "with" in formulas
\DeclareMathOperator{\with}{%
\hspace{30pt} \text{with} \hspace{30pt}
}
```
...

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@ -1,35 +1,3 @@
---
title: Randomness tests of a non-uniform distribution
date: \today
author:
- Giulia Marcer
- Michele Guerini Rocco
institute:
- Università di Milano-Bicocca
theme: metropolis
aspectratio: 169
fontsize: 14pt
mathfont: FiraMath-Regular
sansfont: Fira Sans
header-includes: |
```{=latex}
% Misc
% "thus" in formulas
\DeclareMathOperator{\thus}{%
\hspace{30pt} \Longrightarrow \hspace{30pt}
}
% "et" in formulas
\DeclareMathOperator{\et}{%
\hspace{30pt} \wedge \hspace{30pt}
}
```
...
# Goal
@ -46,13 +14,27 @@ How?
- Applying some hypothesis testings
Why?
## Why?
- They are really similar. Historically, the Moyal distribution was utilized in
The Landau and Moyal PDFs are really similar. Historically, the latter distribution was utilized in
the approximation of the Landau Distribution.
:::: {.columns}
::: {.column width=33%}
\centering
![](images/moyal-photo.jpg){height=130pt}
:::
::: {.column width=33%}
\centering
![](images/mondau-photo.jpg){height=130pt}
:::
::: {.column width=33%}
\centering
![](images/landau-photo.jpg){height=130pt}
:::
::::
# Two similar distributions
## Two similar distributions
:::: {.columns .c}
::: {.column width=50%}
@ -68,8 +50,8 @@ Why?
\begin{center}
Moyal PDF
$$
M(x) = \frac{1}{\sqrt{2 \pi \sigma}} \exp \left( - \frac{x - \mu }{2 \sigma}
- \frac{1}{2} e^{- \frac{x -\mu}{\sigma}} \right)
M(x) = \frac{1}{\sqrt{2 \pi}} \exp \left[ - \frac{1}{2}
\left( x + e^{- x} \right) \right]
$$
\end{center}
:::
@ -86,5 +68,5 @@ Why?
## Two similar distributions
grafici sovrapposti
\centering
![](images/both-pdf.pdf)

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@ -1,81 +1,97 @@
# Moyal PDF
# Moyal distribution
# Moyal PDF
## Moyal PDF
$$
M(x) = \frac{1}{\sqrt{2 \pi}} e^{-\frac{1}{2} \left[ x + e^{-x} \right]}
$$
:::: {.columns .c}
::: {.column width=30%}
\begin{center}
More generally:
\end{center}
:::
::: {.column width=70%}
\begin{center}
\vspace{10pt}
$$
\text{More generally:} \hspace{15pt}
\begin{cases}
\text{location parameter} \mu \\
\text{scale parameter} \sigma
\text{location parameter:} \quad &\mu_M \\
\text{scale parameter:} \quad &\sigma_M
\end{cases}
$$
\end{center}
:::
::::
\vspace{20pt}
\vspace{10pt}
$$
x \rightarrow \frac{x - \mu}{\sigma}
x \rightarrow \frac{x - \mu}{\sigma_M} \thus
M_{\mu \sigma_M}(x) = \frac{1}{\sqrt{2 \pi} \sigma_M}
e^{-\frac{1}{2} \left[ \frac{x - \mu}{\sigma_M} + e^{- \frac{x - \mu}{\sigma_M}} \right]}
$$
## Moyal CDF
The cumulative distribution function $\mathscr{M}(x)$ can be derived from the
The cumulative distribution function $F_M(x)$ can be derived from the
pdf $M(x)$ integrating:
$$
\mathscr{M}(x) = \frac{1}{\sqrt{2 \pi}} \int\limits_{- \infty}^x dy \, M(y)
= \frac{1}{\sqrt{2 \pi}} \int\limits_{- \infty}^x dy \, e^{- \frac{1}{2}}
F_M(x) = \frac{1}{\sqrt{2 \pi}} \int\limits_{- \infty}^x dy \, M(y)
= \frac{1}{\sqrt{2 \pi}} \int\limits_{- \infty}^x dy \, e^{- \frac{y}{2}}
e^{- \frac{1}{2} e^{-y}}
$$
## Moyal CDF
with the change of variable:
\begin{align}
$$
z = \frac{1}{\sqrt{2}} e^{-\frac{y}{2}}
&\thus \frac{dz}{dy} = \frac{-1}{2 \sqrt{2}} e^{-\frac{y}{2}} \\
&\thus dy = -2 \sqrt{2} e^{\frac{y}{2}} dz
\end{align}
hence, the limits of the integral become:
\begin{align}
y \rightarrow - \infty &\thus z \rightarrow + \infty \\
y = x &\thus z = \frac{1}{\sqrt{2}} e^{-\frac{x}{2}} = f(x)
\end{align}
and the CDF can be rewritten as:
$$
\mathscr{M}(x) = \frac{1}{2 \pi} \int\limits_{+ \infty}^{f(x)}
dz \, (- 2 \sqrt{2}) e^{\frac{y}{2}} e^{- \frac{y}{2}} e^{- z^2}
= \frac{-2 \sqrt{2}}{\sqrt{2 \pi}} \int\limits_{+ \infty}^{f(x)}
dz e^{- z^2}
the CDF can be rewritten as:
$$
since the `erf` is defines as:
F_M(x) =
\frac{-2 \sqrt{2}}{\sqrt{2 \pi}} \int\limits_{+ \infty}^{f(x)} dz \, e^{- z^2}
\with f(x) = \frac{e^{- \frac{x}{2}}}{\sqrt{2}}
$$
## Moyal CDF
given the definition of the error function `erf`:
$$
\text{erf} = \frac{2}{\sqrt{\pi}} \int_0^x dy \, e^{-y^2}
$$
one finally gets:
$$
1 = \frac{2}{\sqrt{\pi}} \int_0^{+ \infty} dy \, e^{-y^2}
= \frac{2}{\sqrt{\pi}} \int_0^x dy \, e^{-y^2} +
\frac{2}{\sqrt{\pi}} \int_x^{+ \infty} dy \, e^{-y^2}
= \text{erf}(x) + \frac{2}{\sqrt{\pi}} \int_x^{+ \infty} dy \, e^{-y^2}
F_M(x) = 1 - \text{erf} \left( \frac{e^{- \frac{x}{2}}}{\sqrt{2}} \right)
$$
thus:
## Moyal QDF
The quantile is defined as the inverse of the CDF:
$$
\frac{2}{\sqrt{\pi}} \int_x^{+ \infty} dy \, e^{-y^2}
1 = \frac{2}{\sqrt{\pi}} \int_0^x dy \, e^{-y^2} +
F_M(x) = 1 - \text{erf} \left( \frac{e^{- \frac{x}{2}}}{\sqrt{2}} \right)
$$
hence:
$$
Q(x) = -2 \ln \left[ \sqrt{2} \, \text{erf}^{(-1)} (1 - F_M(x)) \right]
$$
## Moyal median
The median is defined as the point at which $F_M(x) = 1/2$:
\vspace{15pt}
$$
M(x) \thus
m_M = -2 \ln \left[ \sqrt{2} \,
\text{erf}^{(-1)} \left( \frac{1}{2} \right) \right]
$$
\vspace{15pt}
$$
M_{\mu \sigma_M}(x) \thus
m_M = \mu -2 \sigma_M \ln \left[ \sqrt{2} \,
\text{erf}^{(-1)} \left( \frac{1}{2} \right) \right]
$$
## Moyal mode
Peak of the PDF
\vspace{10pt}
$$
\partial_x M(x) = \partial_x \left( \frac{1}{\sqrt{2 \pi}} e^{-\frac{1}{2}
\left( x + e^{-x} \right)} \right)
@ -83,11 +99,43 @@ $$
\left( x + e^{-x} \right)} \left( -\frac{1}{2} \right)
\left( 1 - e^{-x} \right)
$$
\vspace{15pt}
\vspace{10pt}
$$
\partial_x M(x) = 0 \thus x = 0 \thus x = \mu
\partial_x M(x) = 0 \thus \mu_M = 0
$$
\vspace{10pt}
$$
\partial_x M_{\mu \sigma_M}(x) = 0 \thus \mu_M = \mu
$$
## Moyal FWHM
We need to compute the maximum value:
$$
M(\mu) = \frac{1}{\sqrt{2 \pi e}} \thus M(x_{\pm}) = \frac{1}{\sqrt{8 \pi e}}
$$
which leads to:
$$
x_{\pm} + e^{-x_{\pm}} = 1 + 2 \ln(2) \thus
\begin{cases}
x_+ = a + W_0 \left( - \frac{1}{4 e} \right) \\
x_- = a + W_{-1} \left( - \frac{1}{4 e} \right)
\end{cases}
$$
with $a = 1 + 2 \ln(2)$
## Moyal FWHM
$$
\text{FWHM}_L = x_+ - x_- = 3.590806098...
$$
\vspace{15pt}
$$
\thus \mu = m_L
M(x) \thus \text{FWHM}_M = 3.590806098...
$$
\vspace{15pt}
$$
M_{\mu \sigma_M}(x) \thus \text{FWHM}_M = \sigma_M \cdot 3.590806098...
$$

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# Data sample
## Data sample
The $M(x)$ most similar to $L(x)$ is found by imposing:
\vspace{15pt}
$$
\mu_M = \mu_L \sim = 0.22278298...
$$
\vspace{15pt}
$$
\text{FWHM}_M = \text{FWHM}_L = 4.0186457...
\thus \sigma_M = 1.1191486
$$