sections: fix and add a lot of things

This commit is contained in:
Giù Marcer 2020-06-11 18:30:30 +02:00 committed by rnhmjoj
parent 8d71b7a9e1
commit f04b6c6863
6 changed files with 174 additions and 106 deletions

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@ -28,6 +28,14 @@ references:
container-title: Journal of Econometrics
issued:
year: 2015
- type: book
id: silver86
author:
family: Silverman
given: Bernard W.
title: Density Estimation for Statistics and Data Analysis
issued:
year: 1986
header-includes: |
```{=latex}

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@ -177,7 +177,6 @@ $$
exp(-\x*\x) +
exp(-(\x - 1.4)*(\x - 1.4)) +
exp(-(\x - 0.8)*(\x - 0.8)) + 0.1});
\end{tikzpicture}
\end{center}
\setbeamercovered{transparent}
@ -187,7 +186,7 @@ $$
## Sample FWHM
Silverman's rule of thumb:
Silverman's rule of thumb [@silver86]:
$$
\varepsilon = 0.88 \, S_N

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@ -3,14 +3,10 @@
## KS
Quantify distance between expected and observed CDF
. . .
Quantify distance between expected and observed CDF. KS statistic:
:::: {.columns}
::: {.column width=50% .c}
KS statistic:
$$
D_N = \text{sup}_x |F_N(x) - F(x)|
$$
@ -22,23 +18,22 @@ Quantify distance between expected and observed CDF
- sort points in ascending order
- number of points preceding the point normalized by $N$
. . .
:::
::: {.column width=50%}
\setbeamercovered{}
\begin{center}
\begin{tikzpicture}
% axes
\draw [thick, ->] (-2.5,0) -- (0,0) -- (0,4.5);
\draw [thick, ->] (0,0) -- (2.5,0);
% empiric
\draw [cyclamen, fill=cyclamen!20!white] (-2.5,0) rectangle (-1.5,0.5);
\draw [cyclamen, fill=cyclamen!20!white] (-1.5,0) rectangle (-0.9,1);
\draw [cyclamen, fill=cyclamen!20!white] (-0.9,0) rectangle (-0.6,1.5);
\draw [cyclamen, fill=cyclamen!20!white] (-0.6,0) rectangle ( 0.2,2);
\draw [cyclamen, fill=cyclamen!20!white] ( 0.2,0) rectangle ( 0.5,2.5);
\draw [cyclamen, fill=cyclamen!20!white] ( 0.5,0) rectangle ( 0.8,3);
\draw [cyclamen, fill=cyclamen!20!white] ( 0.8,0) rectangle ( 1.6,3.5);
\draw [cyclamen, fill=cyclamen!20!white] (-0.6,0) rectangle ( 0.5,2);
\draw [cyclamen, fill=cyclamen!20!white] ( 0.5,0) rectangle ( 0.7,2.5);
\draw [cyclamen, fill=cyclamen!20!white] ( 0.7,0) rectangle ( 1.2,3);
\draw [cyclamen, fill=cyclamen!20!white] ( 1.2,0) rectangle ( 1.6,3.5);
\draw [cyclamen, fill=cyclamen!20!white] ( 1.6,0) rectangle ( 2.3,4);
\draw [cyclamen, fill=cyclamen!20!white] ( 2.3,0) rectangle ( 2.5,4.5);
% points
@ -46,9 +41,9 @@ Quantify distance between expected and observed CDF
\draw [blue!50!black, fill=blue] (-1.6,-0.1) rectangle (-1.4,0.1); %-1.5
\draw [blue!50!black, fill=blue] (-1,-0.1) rectangle (-0.8,0.1); %-0.9
\draw [blue!50!black, fill=blue] (-0.7,-0.1) rectangle (-0.5,0.1); %-0.6
\draw [blue!50!black, fill=blue] (0.1,-0.1) rectangle (0.3,0.1); % 0.2
\draw [blue!50!black, fill=blue] (0.4,-0.1) rectangle (0.6,0.1); % 0.5
\draw [blue!50!black, fill=blue] (0.7,-0.1) rectangle (0.9,0.1); % 0.8
\draw [blue!50!black, fill=blue] (0.6,-0.1) rectangle (0.8,0.1); % 0.7
\draw [blue!50!black, fill=blue] (1.1,-0.1) rectangle (1.3,0.1); % 1.2
\draw [blue!50!black, fill=blue] (1.5,-0.1) rectangle (1.7,0.1); % 1.6
\draw [blue!50!black, fill=blue] (2.2,-0.1) rectangle (2.4,0.1); % 2.3
% expected
@ -56,7 +51,7 @@ Quantify distance between expected and observed CDF
\draw[domain=-2.5:2.5, yscale=5, smooth, variable=\x, blue, very thick]
plot ({\x}, {((atan(\x)*pi/180) + pi/2)/pi});
\pause
\draw [very thick, cyclamen] (0.8,3.6) -- (0.8,4.05);
\draw [very thick, cyclamen, <->] (0.5,2.5) -- (0.5,3.25);
\end{tikzpicture}
\end{center}
\setbeamercovered{transparent}
@ -70,19 +65,17 @@ $H_0$: points sampled according to $F(x)$
. . .
If $H_0$ is true:
If $H_0$ is true: $\sqrt{N}D_N \xrightarrow{N \rightarrow + \infty} K$
- $\sqrt{N}D_N \xrightarrow{N \rightarrow + \infty} K$
Kolmogorov distribution with CDF:
$K$ Kolmogorov variable with CDF:
$$
P(K \leqslant K_0) = 1 - p = \frac{\sqrt{2 \pi}}{K_0}
P(K \leqslant K_0) = \frac{\sqrt{2 \pi}}{K_0}
\sum_{j = 1}^{+ \infty} e^{-(2j - 1)^2 \pi^2 / 8 K_0^2}
$$
. . .
a $p$-value can be computed
A $p$-value can be computed
- At 95% confidence level, $H_0$ cannot be disproved if $p > 0.05$

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@ -1,53 +1,75 @@
# Trapani test
## A pathological distribution
Because of its fat tail:
\begin{align*}
\mu_1 &= \text{E}\left[|x|\right] \longrightarrow + \infty \\
\mu_2 &= \text{E}\left[|x|^2\right] \longrightarrow + \infty
\end{align*}
. . .
No closed form for parameters $\thus$ numerical estimations
. . .
For a Moyal PDF:
\begin{align*}
E_M[x] &= \mu + \sigma [ \gamma + \ln(2) ] \\
V_M[x] &= \frac{\pi^2 \sigma^2}{2}
\end{align*}
## Infinite moments
- Check whether a moment is finite or infinite
\begin{align*}
\text{infinite} &\thus Landau \\
\text{finite} &\thus Moyal
\end{align*}
. . .
# Trapani test
## Trapani test
::: incremental
- Random variable $\left\{ x_i \right\}$ sampled from a distribution $f$
- Sample moments according to $f$ moments
- Sample moments estimate as $f$ moments
- $H_0$: $\mu_k \longrightarrow + \infty$
- Statistic with 1 dof chi-squared distribution
- Statistic with 1 dof $\chi^2$ distribution
- $p$-value $\hence$ reject or accept $H_0$
:::
## Infinite moments
- Generate a sample $L$ from a Landau PDF
- Generate a sample $M$ from a Moyal PDF
. . .
\vspace{20pt}
:::: {.columns}
::: {.column width=50% .c}
For the Landau PDF:
\begin{align*}
\mu_1 &= \text{E}\left[|x|\right] = + \infty \\
\mu_2 &= \text{E}\left[|x|^2\right] = + \infty
\end{align*}
:::
::: {.column width=50%}
. . .
For the Moyal PDF:
\begin{align*}
\mu_1 &= \text{E}\left[|x|\right] < + \infty \\
\mu_2 &= \text{E}\left[|x|^2\right] < + \infty
\end{align*}
:::
::::
## Infinite moments
- Previous tests: points sampled from Landau PDF?
. . .
- Trapani test: check whether a moment is finite or infinite
\begin{align*}
\text{infinite} &\thus \text{Landau} \\
\text{finite} &\thus \text{not Landau}
\end{align*}
. . .
- Compatibility test with $\mu_k = + \infty$
. . .
- If points were sampled from a Cauchy distribution...
## Trapani test
![](images/cauchy-pdf.pdf)
## Trapani test
- Start with $\left\{ x_i \right\}^N$ and compute $\mu_k$ as:
@ -61,14 +83,19 @@ For a Moyal PDF:
$\left\{ a_j \right\}^r$ as:
$$
a_j = \sqrt{e^{\mu_k}} \cdot \xi_j
\thus G'\left( 0, \sqrt{e^{\mu_k}} \right)
\thus G\left( 0, \sqrt{e^{\mu_k}} \right)
$$
. . .
The greater $\mu^k$, the 'larger' $G'$
- if $\mu_k \longrightarrow + \infty \thus a_j$ distributed uniformly
The greater $\mu^k$, the 'larger' $G\left( 0, \sqrt{e^{\mu_k}} \right)$
$$
\begin{cases}
\mu_k \longrightarrow + \infty \\
r \longrightarrow + \infty
\end{cases}
\thus a_j \text{ distributed uniformly}
$$
## Trapani test
@ -115,9 +142,10 @@ The greater $\mu^k$, the 'larger' $G'$
. . .
If $a_j$ uniformly distributed and $N \rightarrow + \infty$:
If $a_j$ uniformly distributed:
- $\zeta_j (u)$ Bernoulli PDF with $P(\zeta_j (u) = 1) = \frac{1}{2}$
- $\zeta_j (u)$ Bernoulli PDF with $P\left( \zeta_j (u) = 1 \right) = \frac{1}{2}$
$\hence E[\zeta_j]_j = \frac{1}{2} \quad \wedge \quad V[\zeta_j]_j = \frac{1}{4}$
## Trapani test
@ -130,7 +158,7 @@ $$
. . .
If $a_j$ uniformly distributed and $N \rightarrow + \infty$, for the CLT:
If $a_j$ uniformly distributed, for the CLT:
$$
\sum_j \zeta_j (u) \hence
G \left( \frac{r}{2}, \frac{r}{4} \right)
@ -151,15 +179,15 @@ $$
According to L. Trapani [@trapani15]:
- $r = o(N) \hence r = N^{0.75}$
- $\underbar{u} = 1 \quad \wedge \quad \bar{u} = 1$
- $\psi(u) = \chi_{[\underbar{u}, \bar{u}]}$
- $\underbar{u} = -1 \quad \wedge \quad \bar{u} = 1$
- $\psi(u) = \frac{1}{\bar{u} - \underbar{u}} \, \chi_{[\underbar{u}, \bar{u}]}$
. . .
$\mu_k$ must be scale invariant for $k > 1$:
$$
\tilde{\mu_k} = \frac{\mu_k}{ \left( \mu_{\phi} \right)^{k/\phi} }
\mu_k^* = \frac{\mu_k}{ \left( \mu_{\phi} \right)^{k/\phi} }
\with \phi \in (0, k)
$$
@ -167,7 +195,9 @@ $$
## Trapani test
If $\mu_k \ne + \infty \hence \left\{ a_j \right\}$ are not uniformly distributed
\vspace{20pt}
Rewriting:
$$
\vartheta (u) = \frac{2}{\sqrt{r}}
@ -178,4 +208,6 @@ $$
\vspace{20pt}
. . .
Residues become very large $\hence$ $p$-values decreases.

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@ -60,22 +60,35 @@ This leads to more different medians:
\end{align*}
## Compatibility test
## Landau Sample
Comparing results:
Sample N random points following $L(x)$
$$
p = 1 - \text{erf} \left( \frac{t}{\sqrt{2}} \right)\ \with
t = \frac{|x\ex - x\ob|}{\sqrt{\sigma\ex^2 + \sigma\ob^2}}
L(x) = \frac{1}{\pi} \int \limits_{0}^{+ \infty}
dt \, e^{-t \ln(t) -xt} \sin (\pi t)
$$
- $x\ex$ and $x\ob$ are the expected and observed values
- $\sigma\ex$ and $\sigma\ob$ are their absolute errors
. . .
At 95% confidence level, the values are compatible if:
gsl_ran_Landau(gsl_rng)
## Moyal sample
Sample N random points following $M_{\mu \sigma}(x)$
$$
p > 0.05
M_{\mu \sigma}(x) = \frac{1}{\sqrt{2 \pi} \sigma} \exp
\left[ - \frac{1}{2} \left(
\frac{x - \mu}{\sigma}
+ e^{-\frac{x - \mu}{\sigma}} \right) \right]
$$
. . .
reverse sampling
- sampling $y$ uniformly in [0, 1] $\hence x = Q_M(y)$

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@ -1,18 +1,62 @@
# Landau sample
# Results
## Sample
## Compatibility test
Sample N = 50'000 random points following $L(x)$
Comparing sample properties:
$$
L(x) = \frac{1}{\pi} \int \limits_{0}^{+ \infty}
dt \, e^{-t \ln(t) -xt} \sin (\pi t)
p = 1 - \text{erf} \left( \frac{t}{\sqrt{2}} \right)\ \with
t = \frac{|x\ex - x\ob|}{\sqrt{\sigma\ex^2 + \sigma\ob^2}}
$$
- $x\ex$ and $x\ob$ are the expected and observed values
- $\sigma\ex$ and $\sigma\ob$ are their absolute errors
. . .
gsl_ran_Landau(gsl_rng)
At 95% confidence level, the values are compatible if:
$$
p > 0.05
$$
## Compatibility test
\setbeamercovered{}
\begin{center}
\begin{tikzpicture}
%notes
\draw [very thick, gray] (0,0) -- (0,3);
\draw [very thick, gray] (-1.45,1.5) -- (1.45,1.5);
\draw [very thick, gray] (-1.35,1.3) -- (-1.55,1.7);
\draw [very thick, gray] ( 1.35,1.3) -- ( 1.55,1.7);
\node [below] at (0,-0.7) {$x\ex$};
\node [above right] at (1.5,1.5) {$2 \, \sqrt{\sigma\ex^2 + \sigma\ob^2}$};
% axes
\draw [very thick, <->] (-5,4) -- (-5,0) -- (5,0);
% Gaussian
\draw [domain=-5:5, smooth, variable=\x, cyclamen, very thick]
plot ({\x}, {3*exp(-(\x*\x/3))});
\pause
% area
\fill [domain=2:5, smooth, variable=\x, cyclamen!20!white, very thick]
(2,0) -- plot ({\x}, {3*exp(-(\x*\x/3))}) -- (5,0) -- cycle;
\fill [domain=-5:-2, smooth, variable=\x, cyclamen!20!white, very thick]
(-5,0) -- plot ({\x}, {3*exp(-(\x*\x/3))}) -- (-2,0) -- cycle;
% axes
\draw [very thick, <->] (-5,4) -- (-5,0) -- (5,0);
% Gaussian
\draw [domain=-5:5, smooth, variable=\x, cyclamen, very thick]
plot ({\x}, {3*exp(-(\x*\x/3))});
%notes
\draw [thick, cyclamen] (-2,0) -- (-2,0.8);
\draw [thick, cyclamen] ( 2,0) -- ( 2,0.8);
\node at (2,-0.7) {$x\ob$};
\end{tikzpicture}
\end{center}
\setbeamercovered{transparent}
## Compatibility results:
@ -71,27 +115,6 @@ FWHM:
::::
# Moyal sample
## Sample
Sample N = 50'000 random points following $M_{\mu \sigma}(x)$
$$
M_{\mu \sigma}(x) = \frac{1}{\sqrt{2 \pi} \sigma} \exp
\left[ - \frac{1}{2} \left(
\frac{x - \mu}{\sigma}
+ e^{-\frac{x - \mu}{\sigma}} \right) \right]
$$
. . .
reverse sampling
- sampling $y$ uniformly in [0, 1] $\hence x = Q_M(y)$
## Compatibility results:
Median: