make xref = np.broadcast_to(xref, (N, 3)) handling simpler and more elegant

as proposed by mgeier

Author: fs446

doc/examples/wfs-referencing.ipynb

@@ -60,8 +60,7 @@
     "    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",
+    "    xref = np.broadcast_to(xref, array.x.shape)\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",
@@ -177,7 +176,7 @@
     "    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]]))"
+    "    grid, [0, 0, 0])"
    ]
   },
   {
@@ -208,7 +207,7 @@
     "    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]))\n",
+    "    grid, xref)\n",
     "\n",
     "# plot stationary phase rays\n",
     "# one ray connects the virtual source with one activate loudspeaker\n",