Add B streamline plot

plotter.py

@@ -521,6 +521,32 @@ class Plotter(Aggregator, BaseProcessor):
             coordinates="figure",
         )
 
+    def _overlay_B(self, ax_los):
+        ax_h = self._axes_h[ax_los]
+        ax_v = self._axes_v[ax_los]
+        dmap_Bh_node = self.save.get_node("/maps/B_h_{}".format(ax_los))
+        dmap_Bh = dmap_Bh_node.read()
+        dmap_Bv = self.save.get_node("/maps/B_v_{}".format(ax_los)).read()
+
+        vel_red = self.pp_params.plot.vel_red
+        radius = self.save.root.maps._v_attrs.radius
+        center = self.save.root.maps._v_attrs.center
+        lbox = self.save.root._v_attrs.lbox
+
+        map_Bh_red = dmap_Bh[::vel_red, ::vel_red]  # take only a subset of velocities
+        map_Bv_red = dmap_Bv[::vel_red, ::vel_red]
+        nh = map_Bh_red.shape[0]
+        nv = map_Bv_red.shape[1]
+        vec_h = (
+            np.arange(nh) * 2.0 / nh * radius - radius + center[0] + radius / nh
+        ) * lbox
+        vec_v = (
+            np.arange(nv) * 2.0 / nv * radius - radius + center[1] + radius / nv
+        ) * lbox
+        hh, vv = np.meshgrid(vec_h, vec_v)
+
+        P.streamplot(hh, vv, map_Bh_red, map_Bv_red)
+
     def _plot_radial(self, name, ax_los, label=None, xlog=False, ylog=False):
 
         radial_bins = self.save.get_node("/radial/radial_bins_" + ax_los).read()
@@ -945,6 +971,18 @@ class Plotter(Aggregator, BaseProcessor):
                 "Density slice with speed overlay",
                 dependencies=["rho", "speed_h", "speed_v"],
             ),
+            "rho_B": PlotRule(
+                self,
+                partial(
+                    self._plot_map,
+                    "rho",
+                    label=r"$\rho$",
+                    unit=cst.Msun_pc3,
+                    overlays=[self._overlay_B],
+                ),
+                "Density slice with magnetic field overlay",
+                dependencies=["rho", "B_h", "B_v"],
+            ),
             "jeans_ratio": PlotRule(
                 self,
                 partial(