From e8076d1ebc2ff01589d765b2485274c1b9206e78 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Mon, 11 Jan 2021 17:45:08 -0600
Subject: [PATCH] Make plot imports in examples optional

---
 examples/curve-pot.py          | 29 +++++++++++++++++++----------
 examples/expansion-toys.py     |  9 ++++++---
 examples/sym-exp-complexity.py | 26 +++++++++++++++-----------
 3 files changed, 40 insertions(+), 24 deletions(-)

diff --git a/examples/curve-pot.py b/examples/curve-pot.py
index 7ce25a82..7d34ee34 100644
--- a/examples/curve-pot.py
+++ b/examples/curve-pot.py
@@ -1,7 +1,16 @@
 import pyopencl as cl
 import numpy as np
 import numpy.linalg as la
-import matplotlib.pyplot as pt
+
+try:
+    import matplotlib.pyplot as plt
+except ModuleNotFoundError:
+    plt = None
+
+try:
+    from mayavi import mlab
+except ModuleNotFoundError:
+    mlab = None
 
 
 def process_kernel(knl, what_operator):
@@ -248,15 +257,15 @@ def draw_pot_figure(aspect_ratio,
             plotval_vol[outlier_flag] = sum(
                     nb[outlier_flag] for nb in neighbors)/len(neighbors)
 
-        fp.show_scalar_in_mayavi(scale*plotval_vol, max_val=1)
-        from mayavi import mlab
-        mlab.colorbar()
-        if 1:
-            mlab.points3d(
-                    native_curve.pos[0],
-                    native_curve.pos[1],
-                    scale*plotval_c, scale_factor=0.02)
-        mlab.show()
+        if mlab is not None:
+            fp.show_scalar_in_mayavi(scale*plotval_vol, max_val=1)
+            mlab.colorbar()
+            if 1:
+                mlab.points3d(
+                        native_curve.pos[0],
+                        native_curve.pos[1],
+                        scale*plotval_c, scale_factor=0.02)
+            mlab.show()
 
         # }}}
 
diff --git a/examples/expansion-toys.py b/examples/expansion-toys.py
index 12543b93..97c0eceb 100644
--- a/examples/expansion-toys.py
+++ b/examples/expansion-toys.py
@@ -2,7 +2,10 @@ import pyopencl as cl
 import sumpy.toys as t
 import numpy as np
 from sumpy.visualization import FieldPlotter
-import matplotlib.pyplot as plt
+try:
+    import matplotlib.pyplot as plt
+except ImportError:
+    plt = None
 
 
 def main():
@@ -22,7 +25,7 @@ def main():
 
     fp = FieldPlotter([3, 0], extent=8)
 
-    if 0:
+    if 0 and plt is not None:
         t.logplot(fp, pt_src, cmap="jet")
         plt.colorbar()
         plt.show()
@@ -37,7 +40,7 @@ def main():
     diff = lexp2 - pt_src
 
     print(t.l_inf(diff, 1.2, center=lexp2.center))
-    if 1:
+    if 1 and plt is not None:
         t.logplot(fp, diff, cmap="jet", vmin=-3, vmax=0)
         plt.colorbar()
         plt.show()
diff --git a/examples/sym-exp-complexity.py b/examples/sym-exp-complexity.py
index bde21c42..49e20ead 100644
--- a/examples/sym-exp-complexity.py
+++ b/examples/sym-exp-complexity.py
@@ -11,6 +11,10 @@ from sumpy.expansion.multipole import (
         HelmholtzConformingVolumeTaylorMultipoleExpansion,
         )
 from sumpy.e2e import E2EFromCSR
+try:
+    import matplotlib.pyplot as plt
+except ModuleNotFoundError:
+    plt = None
 
 
 def find_flops():
@@ -59,28 +63,28 @@ def plot_flops():
         flops = [62, 300, 914, 2221, 4567, 8405, 14172, 22538, 34113]
         filename = "laplace-m2l-complexity-3d.pdf"
 
-    elif 0:
+    elif 1:
         case = "2D Laplace M2L"
         orders = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
                 18, 19, 20]
         flops = [36, 99, 193, 319, 476, 665, 889, 1143, 1429, 1747, 2097, 2479, 2893,
                 3339, 3817, 4327, 4869, 5443, 6049, 6687]
         filename = "laplace-m2l-complexity-2d.pdf"
-    elif 1:
+    elif 0:
         case = "2D Helmholtz M2L"
         orders = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
         flops = [45, 194, 474, 931, 1650, 2632, 3925, 5591, 7706, 10272]
         filename = "helmholtz-m2l-complexity-2d.pdf"
 
-    import matplotlib.pyplot as plt
-    plt.rc("font", size=16)
-    plt.title(case)
-    plt.ylabel("Flop count")
-    plt.xlabel("Expansion order")
-    plt.loglog(orders, flops, "o-")
-    plt.grid()
-    plt.tight_layout()
-    plt.savefig(filename)
+    if plt is not None:
+        plt.rc("font", size=16)
+        plt.title(case)
+        plt.ylabel("Flop count")
+        plt.xlabel("Expansion order")
+        plt.loglog(orders, flops, "o-")
+        plt.grid()
+        plt.tight_layout()
+        plt.savefig(filename)
 
 
 if __name__ == "__main__":
-- 
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