xref array handling nicer

mgeier suggested to improve np.array([[0, 0, 0]]*array.x.shape[0]) and np.array([xref]*array.x.shape[0]) by a handling in sound_field()

Author: fs446

doc/examples/wfs-referencing.ipynb

@@ -39,7 +39,8 @@
    "outputs": [],
    "source": [
     "R = 1.5  # radius [m] of circular loudspeaker array\n",
-    "array = sfs.array.circular(N=64, R=R)  # with N loudspeakers\n",
+    "N = 64  # loudspeakers\n",
+    "array = sfs.array.circular(N=N, R=R)\n",
     "grid = sfs.util.xyz_grid([-2, 2], [-2, 2], 0, spacing=0.02)\n",
     "\n",
     "xs = -4, 0, 0  # virtual point source on negative x-axis\n",
@@ -59,6 +60,8 @@
     "    sfs.plot2d.amplitude(p, grid, vmax=2, vmin=-2, ax=ax_amp)\n",
     "    sfs.plot2d.level(p, grid, vmax=6, vmin=-6, ax=ax_lvl)\n",
     "    sfs.plot2d.level_contour(p, grid, levels=[0], colors='w', ax=ax_lvl)\n",
+    "    if xref.shape[0] != N:\n",
+    "        xref = np.broadcast_to(xref, (N, 3))\n",
     "    for ax in ax_amp, ax_lvl:\n",
     "        sfs.plot2d.loudspeakers(array.x, array.n, selection, size=0.125, ax=ax)\n",
     "    ax_lvl.scatter(*xref[selection, :2].T, marker='o', s=20, c='lightsalmon',\n",
@@ -174,7 +177,7 @@
     "    omega, array.x, array.n, xs)\n",
     "p_point = sound_field(\n",
     "    d * normalize_gain, selection, array, secondary_source,\n",
-    "    grid, np.array([[0, 0, 0]]*array.x.shape[0]))"
+    "    grid, np.array([[0, 0, 0]]))"
    ]
   },
   {
@@ -205,7 +208,7 @@
     "    omega, array.x, array.n, xs, xref=xref)\n",
     "p_point = sound_field(\n",
     "    d * normalize_gain, selection, array, secondary_source,\n",
-    "    grid, np.array([xref]*array.x.shape[0]))\n",
+    "    grid, np.array([xref]))\n",
     "\n",
     "# plot stationary phase rays\n",
     "# one ray connects the virtual source with one activate loudspeaker\n",