removed bare matplotlib imports in non-test source files. (#1035)

Author: robfalck

dymos/examples/brachistochrone/test/ex_brachistochrone.py

@@ -1,4 +1,3 @@
-import matplotlib
 import numpy as np
 
 import openmdao.api as om
@@ -8,10 +7,6 @@
 from dymos.examples.brachistochrone.brachistochrone_ode import BrachistochroneODE
 
 
-SHOW_PLOTS = True
-matplotlib.use('Agg')
-
-
 @require_pyoptsparse(optimizer='SLSQP')
 def brachistochrone_min_time(transcription='gauss-lobatto', num_segments=8, transcription_order=3,
                              compressed=True, optimizer='SLSQP', run_driver=True, force_alloc_complex=False,

dymos/examples/cart_pole/animate_cartpole.py

@@ -1,10 +1,11 @@
 import numpy as np
-import matplotlib.pyplot as plt
-import matplotlib.patches as patches
-from matplotlib import animation
 
 
 def animate_cartpole(x, theta, force, interval=20, force_scaler=0.1, save_gif=False, gif_fps=20):
+
+    import matplotlib.pyplot as plt
+    import matplotlib.patches as patches
+    from matplotlib import animation
     # x: time history of cart location, 1d vector
     # theta: time history of pole angle, 1d vector
     # force: control input force

dymos/examples/plotting.py

@@ -1,6 +1,3 @@
-import matplotlib.pyplot as plt
-
-
 def plot_results(axes, title, figsize=(10, 8), p_sol=None, p_sim=None):
     """
     Plot the timeseries results of a Dymos problem using matplotlib.
@@ -22,6 +19,8 @@ def plot_results(axes, title, figsize=(10, 8), p_sol=None, p_sim=None):
         The Figure object and sequence of axes associated with the plot.
 
     """
+    import matplotlib.pyplot as plt
+
     nrows = len(axes)
 
     fig, axs = plt.subplots(nrows=nrows, ncols=1, figsize=figsize)

dymos/visualization/timeseries_plots.py

@@ -4,11 +4,6 @@
 
 import numpy as np
 
-import matplotlib
-import matplotlib.pyplot as plt
-import matplotlib.lines as mlines
-import matplotlib.patches as mpatches
-
 import openmdao.api as om
 from .._options import options as dymos_options
 
@@ -55,6 +50,11 @@ def _get_phases_node_in_problem_metadata(node, path=""):
 def _mpl_timeseries_plots(time_units, var_units, phase_names, phases_node_path,
                           last_solution_case, last_simulation_case, plot_dir_path,
                           dpi, include_parameters):
+    import matplotlib
+    import matplotlib.pyplot as plt
+    import matplotlib.lines as mlines
+    import matplotlib.patches as mpatches
+
     # get ready to plot
     backend_save = plt.get_backend()
     plt.switch_backend('Agg')