Commit 8663c42c authored by Jamal KHAN's avatar Jamal KHAN

Fix formatting

parent d94f86b8
...@@ -12,7 +12,7 @@ ...@@ -12,7 +12,7 @@
#+HTML_HEAD: <script type="text/javascript" src="http://www.pirilampo.org/styles/readtheorg/js/readtheorg.js"></script> #+HTML_HEAD: <script type="text/javascript" src="http://www.pirilampo.org/styles/readtheorg/js/readtheorg.js"></script>
* Asking the maths library * Asking the maths library
My computer tells me that \pi is approximattively My computer tells me that $\pi$ is /approximatively/
#+begin_src R :results output :session *R* :exports both #+begin_src R :results output :session *R* :exports both
pi pi
#+end_src #+end_src
...@@ -20,9 +20,9 @@ pi ...@@ -20,9 +20,9 @@ pi
#+RESULTS: #+RESULTS:
: [1] 3.141593 : [1] 3.141593
* Buffon;s needle * Buffon's needle
Applying the method of [[https://en.wikipedia.org/wiki/Buffon's_needle_problem][Buffon's needle]], we get the **approximation** Applying the method of [[https://en.wikipedia.org/wiki/Buffon%2527s_needle_problem][Buffon's needle]] we get the *approximation*
#+begin_src R :results output :session *R* :exports both #+begin_src R :results output :session *R* :exports results
set.seed(42) set.seed(42)
N = 100000 N = 100000
x = runif(N) x = runif(N)
...@@ -31,15 +31,15 @@ theta = pi/2*runif(N) ...@@ -31,15 +31,15 @@ theta = pi/2*runif(N)
#+end_src #+end_src
#+RESULTS: #+RESULTS:
:
: [1] 3.14327 : [1] 3.14327
* 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 A method that is easier to understand and does not make use of the
function is based on the fact that if $X\simU(0,1)$ and $Y\simU(0,1)$, then $\sin$ function is based on the fact that if $X\simU(0,1)$ and
$P[X^2+Y^2 \le1]=\pi/4$ (see [[https://en.wikipedia.org/wiki/Monte_Carlo_method]["Monte Carlo method" on Wikipedia]]). The $Y\simU(0,1)$, then $P[X^2+Y^2 \le1]=\pi/4$ (see [[https://en.wikipedia.org/wiki/Monte_Carlo_method]["Monte Carlo method" on
following code uses this approach: Wikipedia]]). The following code uses this approach:
#+begin_src R :results output graphics :file (org-babel-temp-file "figure" ".png") :exports both :width 600 :height 400 :session *R*
#+begin_src R :results output graphics :file figure_pi_mc1.png :exports both :width 600 :height 400 :session *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))
...@@ -49,10 +49,10 @@ ggplot(df, aes(x=X, y=Y, color=Accept)) + geom_point(alpha=.2) + coord_fixed() + ...@@ -49,10 +49,10 @@ ggplot(df, aes(x=X, y=Y, color=Accept)) + geom_point(alpha=.2) + coord_fixed() +
#+end_src #+end_src
#+RESULTS: #+RESULTS:
[[file:/tmp/babel-9oTMJE/figure0FnJcH.png]] [[file:figure_pi_mc1.png]]
It is then straightforward to obtain a (not really good) approximation It is then 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: to \pi by counting how many times, on average, $X^2 + Y^2$ is smaller than 1:
#+begin_src R :results output :session *R* :exports both #+begin_src R :results output :session *R* :exports both
4*mean(df$Accept) 4*mean(df$Accept)
#+end_src #+end_src
......
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