slides: start writing something

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Giù Marcer 2020-06-05 16:36:19 +02:00 committed by rnhmjoj
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@ -16,6 +16,8 @@ sansfont: Fira Sans
header-includes: |
```{=latex}
% Misc
% "thus" in formulas
\DeclareMathOperator{\thus}{%
\hspace{30pt} \Longrightarrow \hspace{30pt}
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\DeclareMathOperator{\et}{%
\hspace{30pt} \wedge \hspace{30pt}
}
```
...
# Goal
## Goal
What?
- Generate a sample of points from a Moyal PDF
- Prove it truly comes from it and not from a Landau PDF
How?
- Applying some hypothesis testings
Why?
- They are really similar. Historically, the Moyal distribution was utilized in
the approximation of the Landau Distribution.
# Two similar distributions
:::: {.columns .c}
::: {.column width=50%}
\begin{center}
Landau PDF
$$
L(x) = \frac{1}{\pi} \int \limits_{0}^{+ \infty}
dt \, e^{-t \ln(t) -xt} \sin (\pi t)
$$
\end{center}
:::
::: {.column width=50%}
\begin{center}
Moyal PDF
$$
M(x) = \frac{1}{\sqrt{2 \pi \sigma}} \exp \left( - \frac{x - \mu }{2 \sigma}
- \frac{1}{2} e^{- \frac{x -\mu}{\sigma}} \right)
$$
\end{center}
:::
::::
:::: {.columns .c}
::: {.column width=50%}
![](images/landau-pdf.pdf)
:::
::: {.column width=50%}
![](images/moyal-pdf.pdf)
:::
::::
## Two similar distributions
grafici sovrapposti

93
slides/sections/2.md Normal file
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# 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}
$$
\begin{cases}
\text{location parameter} \mu \\
\text{scale parameter} \sigma
\end{cases}
$$
\end{center}
:::
::::
\vspace{20pt}
$$
x \rightarrow \frac{x - \mu}{\sigma}
$$
## Moyal CDF
The cumulative distribution function $\mathscr{M}(x)$ can be derived from the
pdf $M(x)$ integrating:
$$
\mathscr{M}(x) = \frac{1}{\sqrt{2 \pi}} \int\limits_{- \infty}^x dy \, M(y)
= \frac{1}{\sqrt{2 \pi}} \int\limits_{- \infty}^x dy \, e^{- \frac{1}{2}}
e^{- \frac{1}{2} e^{-y}}
$$
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:
$$
\mathscr{M}(x) = \frac{1}{2 \pi} \int\limits_{+ \infty}^{f(x)}
dz \, (- 2 \sqrt{2}) e^{\frac{y}{2}} e^{- \frac{y}{2}} e^{- z^2}
= \frac{-2 \sqrt{2}}{\sqrt{2 \pi}} \int\limits_{+ \infty}^{f(x)}
dz e^{- z^2}
$$
since the `erf` is defines as:
$$
\text{erf} = \frac{2}{\sqrt{\pi}} \int_0^x dy \, e^{-y^2}
$$
$$
1 = \frac{2}{\sqrt{\pi}} \int_0^{+ \infty} dy \, e^{-y^2}
= \frac{2}{\sqrt{\pi}} \int_0^x dy \, e^{-y^2} +
\frac{2}{\sqrt{\pi}} \int_x^{+ \infty} dy \, e^{-y^2}
= \text{erf}(x) + \frac{2}{\sqrt{\pi}} \int_x^{+ \infty} dy \, e^{-y^2}
$$
thus:
$$
\frac{2}{\sqrt{\pi}} \int_x^{+ \infty} dy \, e^{-y^2}
1 = \frac{2}{\sqrt{\pi}} \int_0^x dy \, e^{-y^2} +
$$
## Moyal mode
Peak of the PDF
$$
\partial_x M(x) = \partial_x \left( \frac{1}{\sqrt{2 \pi}} e^{-\frac{1}{2}
\left( x + e^{-x} \right)} \right)
= \frac{1}{\sqrt{2 \pi}} e^{-\frac{1}{2}
\left( x + e^{-x} \right)} \left( -\frac{1}{2} \right)
\left( 1 - e^{-x} \right)
$$
\vspace{15pt}
$$
\partial_x M(x) = 0 \thus x = 0 \thus x = \mu
$$
\vspace{15pt}
$$
\thus \mu = m_L
$$