edits

parent 91b70c6e
...@@ -6,6 +6,7 @@ ...@@ -6,6 +6,7 @@
"source": [ "source": [
"# On the computation of $\\pi$\n", "# On the computation of $\\pi$\n",
"## Asking the maths library\n", "## Asking the maths library\n",
"\n",
"My computer tells me that $\\pi$ is *approximatively*" "My computer tells me that $\\pi$ is *approximatively*"
] ]
}, },
...@@ -32,7 +33,7 @@ ...@@ -32,7 +33,7 @@
"metadata": {}, "metadata": {},
"source": [ "source": [
"## Buffon’s needle\n", "## Buffon’s needle\n",
"Applying the method of [Buffon’s needle](https://en.wikipedia.org/wiki/Buffon%27s_needle_problem), we get the **approximation**" "Applying the method of [Buffon’s needle](https://en.wikipedia.org/wiki/Buffon%27s_needle_problem), we get the __approximation__"
] ]
}, },
{ {
...@@ -65,12 +66,12 @@ ...@@ -65,12 +66,12 @@
"metadata": {}, "metadata": {},
"source": [ "source": [
"## Using a surface fraction argument\n", "## Using a surface fraction argument\n",
"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[X$^2$ + Y$^2$ ≤ 1] = $\\pi$/4* (see [\"Monte Carlo method\"on Wikipedia](https://en.wikipedia.org/wiki/Monte_Carlo_method)). 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:"
] ]
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": 3, "execution_count": 5,
"metadata": {}, "metadata": {},
"outputs": [ "outputs": [
{ {
...@@ -89,12 +90,15 @@ ...@@ -89,12 +90,15 @@
"source": [ "source": [
"%matplotlib inline\n", "%matplotlib inline\n",
"import matplotlib.pyplot as plt\n", "import matplotlib.pyplot as plt\n",
"\n",
"np.random.seed(seed=42)\n", "np.random.seed(seed=42)\n",
"N = 1000\n", "N = 1000\n",
"x = np.random.uniform(size=N, low=0, high=1)\n", "x = np.random.uniform(size=N, low=0, high=1)\n",
"y = np.random.uniform(size=N, low=0, high=1)\n", "y = np.random.uniform(size=N, low=0, high=1)\n",
"\n",
"accept = (x*x+y*y) <= 1\n", "accept = (x*x+y*y) <= 1\n",
"reject = np.logical_not(accept)\n", "reject = np.logical_not(accept)\n",
"\n",
"fig, ax = plt.subplots(1)\n", "fig, ax = plt.subplots(1)\n",
"ax.scatter(x[accept], y[accept], c='b', alpha=0.2, edgecolor=None)\n", "ax.scatter(x[accept], y[accept], c='b', alpha=0.2, edgecolor=None)\n",
"ax.scatter(x[reject], y[reject], c='r', alpha=0.2, edgecolor=None)\n", "ax.scatter(x[reject], y[reject], c='r', alpha=0.2, edgecolor=None)\n",
...@@ -105,8 +109,7 @@ ...@@ -105,8 +109,7 @@
"cell_type": "markdown", "cell_type": "markdown",
"metadata": {}, "metadata": {},
"source": [ "source": [
"It is then straightforward to obtain a (not really good) approximation to $\\pi$ by counting how\n", "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:"
"many times, on average, $X^2 + Y^2$ is smaller than 1:"
] ]
}, },
{ {
......
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