DOC: convert image source example script to a Jupyter notebook

doc/examples/index.rst

@@ -20,3 +20,4 @@ Or Jupyter notebooks, which are also available online as interactive examples:
     :maxdepth: 1
 
     modal-room-acoustics
+    mirror-image-source-model

doc/examples/mirror-image-source-model.ipynb

@@ -0,0 +1,169 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Mirror Image Sources and the Sound Field in a Rectangular Room"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import matplotlib.pyplot as plt\n",
+    "import numpy as np\n",
+    "import sfs"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "L = 2, 2.7, 3  # room dimensions\n",
+    "x0 = 1.2, 1.7, 1.5  # source position\n",
+    "max_order = 2  # maximum order of image sources\n",
+    "coeffs = .8, .8, .6, .6, .7, .7  # wall reflection coefficients"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## 2D Mirror Image Sources"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "xs, wall_count = sfs.util.image_sources_for_box(x0[0:2], L[0:2], max_order)\n",
+    "source_strength = np.prod(coeffs[0:4]**wall_count, axis=1)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from matplotlib.patches import Rectangle"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "fig, ax = plt.subplots()\n",
+    "ax.scatter(*xs.T, source_strength * 20)\n",
+    "ax.add_patch(Rectangle((0, 0), L[0], L[1], fill=False))\n",
+    "ax.set_xlabel('x / m')\n",
+    "ax.set_ylabel('y / m')\n",
+    "ax.axis('equal');"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Monochromatic Sound Field"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "omega = 2 * np.pi * 1000  # angular frequency"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "grid = sfs.util.xyz_grid([0, L[0]], [0, L[1]], 1.5, spacing=0.02)\n",
+    "P = sfs.mono.source.point_image_sources(omega, x0, [1, 0, 0], grid, L,\n",
+    "                                        max_order, coeffs=coeffs)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "sfs.plot.soundfield(P, grid, xnorm=[L[0]/2, L[1]/2, L[2]/2]);"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Spatio-temporal Impulse Response"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "fs = 44100  # sample rate\n",
+    "signal = [1, 0, 0], fs"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "grid = sfs.util.xyz_grid([0, L[0]], [0, L[1]], 1.5, spacing=0.005)\n",
+    "p = sfs.time.source.point_image_sources(x0, signal, 0.004, grid, L, max_order,\n",
+    "                                        coeffs=coeffs)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "sfs.plot.level(p, grid)\n",
+    "sfs.plot.virtualsource_2d(x0)"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.7.2+"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}