Merge branch 'release/v0.2.1' of github.com:xsuite/xmask into release…

…/v0.2.1

examples/hllhc15_collision/004_footprint.py

@@ -0,0 +1,44 @@
+import numpy as np
+import matplotlib.pyplot as plt
+
+import xtrack as xt
+
+
+collider = xt.Multiline.from_json('./collider_03_tuned_bb_on.json')
+collider.build_trackers()
+
+fp0 = collider['lhcb1'].get_footprint(nemitt_x=2.5e-6, nemitt_y=2.5e-6)
+
+fp_polar = collider['lhcb1'].get_footprint(
+    nemitt_x=2.5e-6, nemitt_y=2.5e-6,
+    linear_rescale_on_knobs=[
+        xt.LinearRescale(knob_name='beambeam_scale', v0=0.0, dv=0.1)]
+    )
+
+
+fp_ua = collider['lhcb1'].get_footprint(
+    nemitt_x=2.5e-6, nemitt_y=2.5e-6,
+    mode='uniform_action_grid',
+    linear_rescale_on_knobs=[
+        xt.LinearRescale(knob_name='beambeam_scale', v0=0.0, dv=0.1)]
+    )
+
+
+plt.close('all')
+
+fig1 = plt.figure(1)
+ax1 = fig1.add_subplot(111)
+fp0.plot(ax=ax1, label='no rescale bb')
+plt.suptitle('Polar mode (default) - no rescale on beambeam')
+
+fig2 = plt.figure(2)
+ax2 = fig2.add_subplot(111, sharex=ax1, sharey=ax1)
+fp_polar.plot(ax=ax2, label='rescale bb')
+plt.suptitle('Polar mode (default) - linear rescale on beambeam')
+
+fig3 = plt.figure(3)
+ax3 = fig3.add_subplot(111, sharex=ax1, sharey=ax1)
+fp_ua.plot()
+plt.suptitle('Uniform action grid mode - linear rescale on beambeam')
+
+plt.show()