From b4dec54a48b23c071560b4f85b2b7267c0f4ab26 Mon Sep 17 00:00:00 2001 From: 16fd6933414ad4ae0fb1412e7effdbc7 <16fd6933414ad4ae0fb1412e7effdbc7@app-learninglab.inria.fr> Date: Thu, 11 Jun 2020 20:03:42 +0000 Subject: [PATCH] Delete toy_document_en.Rmd --- module2/exo1/toy_document_en.Rmd | 59 -------------------------------- 1 file changed, 59 deletions(-) delete mode 100644 module2/exo1/toy_document_en.Rmd diff --git a/module2/exo1/toy_document_en.Rmd b/module2/exo1/toy_document_en.Rmd deleted file mode 100644 index 1ebc4bf..0000000 --- a/module2/exo1/toy_document_en.Rmd +++ /dev/null @@ -1,59 +0,0 @@ -# On the computation of pi - -TEGEGNe - -11 June 2020 - -## Asking the maths library - -My computer tells me that π is approximatively - ---- -pi - - -``` -## [1] 3.141593 -``` - -## Buffon’s needle - -Applying the method of (https://fr.wikipedia.org/wiki/Aiguille_de_Buffon), we get the (**approximation**) - -``` -set.seed(42) -N = 100000 -x = runif(N) -theta = pi/2*runif(N) -2/(mean(x+sin(theta)>1)) -``` - -``` -## [1] 3.14327 -``` - -## 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 “Mhttps://en.wikipedia.org/wiki/Monte_Carlo_method") The following code uses this approach: - -``` -set.seed(42) -N = 1000 -df = data.frame(X = runif(N), Y = runif(N)) -df$Accept = (df$X**2 + df$Y**2 <=1) -library(ggplot2) -ggplot(df, aes(x=X,y=Y,color=Accept)) + geom_point(alpha=.2) + coord_fixed() + theme_bw() -``` - -It is therefore straightforward to obtain a (not really good) approximation to π by counting how many times, on average, (**X2**)+(**Y2**) is smaller than -1 : - -``` -4*mean(df$Accept) -``` - -``` -## [1] 3.156 -``` - - -- 2.18.1