Update toy_document_en.Rmd

parent 00e7d853
--- ---
title: "Your title" title: "On the computation of pi"
author: "Your name" author: "Jayashri Govindan"
date: "Today's date" date: "23 Octobre 2023"
output: html_document output: html_document
editor_options:
markdown:
wrap: 72
--- ---
On the computation of pi ```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```
Arnaud Legrand ## Asking the maths library
25 juin 2018 My computer tells me that $\pi$ is *approximatively*
Asking the maths library # On the computation of pi
*Arnaud Legrand*
*25 juin 2018*
## Asking the maths library
My computer tells me that π is approximatively My computer tells me that π is approximatively
{r} ```{r}
pi pi
```
Buffon's needle ## Buffon's needle
Applying the method of Buffon's needle, we get the approximation Applying the method of [Buffon's needle](https://en.wikipedia.org/wiki/Buffon%27s_needle_problem), we get the approximation
{r} ```{r}
set.seed(42) set.seed(42)
N = 100000 N = 100000
x = runif(N) x = runif(N)
theta = pi/2*runif(N) theta = pi/2*runif(N)
2/(mean(x+sin(theta)>1)) 2/(mean(x+sin(theta)>1))
```
Using a surface fraction argument ## Using a surface fraction argument
A method that is easier to understand and does not make use of the sin function is based on the fact that if X∼U(0,1) and Y∼U(0,1), then P[X2+Y2≤1]=π/4 (see "Monte Carlo method" on Wikipedia). The following code uses this approach: A method that is easier to understand and does not make use of the $\sin$ function is based on the fact that if $X\sim U(0,1)$ and $Y\sim U(0,1)$, then $P[X^2+Y^2\leq 1] = \pi/4$ (see ["Monte Carlo method" on Wikipedia](https://en.wikipedia.org/wiki/Monte_Carlo_method)). The following code uses this approach:
{r} ```{r}
set.seed(42) set.seed(42)
N = 1000 N = 1000
df = data.frame(X = runif(N), Y = runif(N)) df = data.frame(X = runif(N), Y = runif(N))
df$Accept = (df$X**2 + df$Y**2 <=1) df$Accept = (df$X**2 + df$Y**2 <=1)
library(ggplot2) library(ggplot2)
ggplot(df, aes(x=X,y=Y,color=Accept)) + geom_point(alpha=.2) + coord_fixed() + theme_bw() ggplot(df, aes(x=X,y=Y,color=Accept)) + geom_point(alpha=.2) + coord_fixed() + theme_bw()
```
It is therefore straightforward to obtain a (not really good) approximation to π by counting how many times, on average, X2 + Y2  is smaller than 1 It is therefore straightforward to obtain a (not really good) approximation to $\pi$ by counting how many times, on average, $X^2 + Y^2$ , is smaller than 1
{r} ```{r}
4*mean(df$Accept) 4*mean(df$Accept)
```
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