Bugfix example16: minor changes to magnification axis

examples/example_16/ulens_model_fit.py

@@ -38,7 +38,7 @@
 except Exception:
     raise ImportError('\nYou have to install MulensModel first!\n')
 
-__version__ = '0.34.3'
+__version__ = '0.34.4'
 
 
 class UlensModelFit(object):
@@ -3096,32 +3096,41 @@ def _mark_second_Y_axis_in_best_plot(self):
         Mark the second (right-hand side) scale for Y axis in
         the best model plot
         """
-        settings = self._plots['best model']["second Y scale"]
-        magnifications = settings['magnifications']
-        color = settings.get("color", "red")
-        label = settings.get("label", "magnification")
-        labels = settings.get("labels")
-
-        ylim = plt.ylim()
-        ax2 = plt.gca().twinx()
-        (A_min, A_max, sb_fluxes) = self._second_Y_axis_get_fluxes(ylim)
+        (magnifications, labels, ylim, ax2) = self._second_Y_axis_settings()
+        (A_range, ref_fluxes) = self._second_Y_axis_get_fluxes(ylim)
         out1, out2 = False, False
         if magnifications == "optimal":
             (magnifications, labels, out1) = self._second_Y_axis_optimal(
-                ax2, A_min, A_max)
-        flux = sb_fluxes[0] * magnifications + sb_fluxes[1]
+                ax2, *A_range)
+            self._second_Y_axis_minor_ticks(ax2, magnifications, ref_fluxes)
+        flux = ref_fluxes[0] * np.array(magnifications) + ref_fluxes[1]
         out2 = self._second_Y_axis_warnings(flux, labels, magnifications,
-                                            A_min, A_max)
+                                            *A_range)
         if out1 or out2:
             ax2.get_yaxis().set_visible(False)
             return
 
         ticks = mm.Utils.get_mag_from_flux(flux)
+        ax2.set_yticks(ticks, labels)
+        ax2.set_ylim(ylim[0], ylim[1])
+
+    def _second_Y_axis_settings(self):
+        """
+        Get and apply settings for the second Y axis
+        """
+        settings = self._plots['best model']["second Y scale"]
+        magnifications = settings['magnifications']
+        color = settings.get("color", "black")
+        label = settings.get("label", "Magnification")
+        labels = settings.get("labels")
+        ylim = plt.ylim()
+
+        ax2 = plt.gca().twinx()
         ax2.set_ylabel(label).set_color(color)
         ax2.spines['right'].set_color(color)
-        ax2.set_ylim(ylim[0], ylim[1])
-        ax2.tick_params(axis='y', colors=color)
-        plt.yticks(ticks, labels, color=color)
+        ax2.tick_params(axis='y', direction="in", which="both", colors=color)
+
+        return (magnifications, labels, ylim, ax2)
 
     def _second_Y_axis_get_fluxes(self, ylim):
         """
@@ -3135,7 +3144,7 @@ def _second_Y_axis_get_fluxes(self, ylim):
         A_min = (flux_min - blend_flux) / total_source_flux
         A_max = (flux_max - blend_flux) / total_source_flux
 
-        return (A_min, A_max, [total_source_flux, blend_flux])
+        return ([A_min, A_max], [total_source_flux, blend_flux])
 
     def _second_Y_axis_optimal(self, ax2, A_min, A_max):
         """
@@ -3163,6 +3172,18 @@ def _second_Y_axis_optimal(self, ax2, A_min, A_max):
 
         return (A_values[fnum < 4], labels[fnum < 4].tolist(), False)
 
+    def _second_Y_axis_minor_ticks(self, ax2, A_values, ref_fluxes):
+        """
+        Get minor ticks for magnification axis from matplotlib
+        """
+        ax2.minorticks_on()
+        minor_ticks_A = ax2.yaxis.get_ticklocs(minor=True)
+        minor_ticks_A = minor_ticks_A[~np.isin(minor_ticks_A, A_values)]
+
+        minor_ticks_flux = ref_fluxes[0] * minor_ticks_A + ref_fluxes[1]
+        minor_ticks_mag = mm.Utils.get_mag_from_flux(minor_ticks_flux)
+        ax2.set_yticks(minor_ticks_mag, minor=True)
+
     def _second_Y_axis_warnings(self, flux, labels, A_values, A_min, A_max):
         """
         Issue warnings for negative flux or bad range of magnificaitons