add direct visual comparison of buffer/rFFTW interps

tests/test_interpolation2.py

+#######################################################################
+#                                                                     #
+#  Copyright 2015 Max Planck Institute                                #
+#                 for Dynamics and Self-Organization                  #
+#                                                                     #
+#  This file is part of bfps.                                         #
+#                                                                     #
+#  bfps is free software: you can redistribute it and/or modify       #
+#  it under the terms of the GNU General Public License as published  #
+#  by the Free Software Foundation, either version 3 of the License,  #
+#  or (at your option) any later version.                             #
+#                                                                     #
+#  bfps is distributed in the hope that it will be useful,            #
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of     #
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the      #
+#  GNU General Public License for more details.                       #
+#                                                                     #
+#  You should have received a copy of the GNU General Public License  #
+#  along with bfps.  If not, see <http://www.gnu.org/licenses/>       #
+#                                                                     #
+# Contact: Cristian.Lalescu@ds.mpg.de                                 #
+#                                                                     #
+#######################################################################
+
+
+
+import numpy as np
+from base import *
+import matplotlib.pyplot as plt
+
+if __name__ == '__main__':
+    opt = parser.parse_args(
+            ['-n', '32',
+             '--run',
+             '--ncpu', '2',
+             '--initialize',
+             '--neighbours', '4',
+             '--smoothness', '1',
+             '--nparticles', '4225',
+             '--niter_todo', '1',
+             '--niter_stat', '1',
+             '--niter_part', '1',
+             '--niter_out', '1',
+             '--wd', 'interp'] +
+            sys.argv[1:])
+    c = bfps.NavierStokes(
+            name = 'test_interpolation',
+            use_fftw_wisdom = False,
+            frozen_fields = True)
+    c.pars_from_namespace(opt)
+    c.fill_up_fluid_code()
+    c.add_interpolator(
+            name = 'buffered',
+            neighbours = opt.neighbours,
+            smoothness = opt.smoothness,
+            class_name = 'interpolator')
+    c.add_interpolator(
+            name = 'rFFTW',
+            neighbours = opt.neighbours,
+            smoothness = opt.smoothness,
+            class_name = 'rFFTW_interpolator')
+    c.add_particles(
+            integration_steps = 1,
+            interpolator = 'buffered',
+            class_name = 'particles')
+    c.add_particles(
+            integration_steps = 1,
+            interpolator = 'rFFTW',
+            class_name = 'particles')
+    c.finalize_code()
+    c.write_src()
+    c.write_par()
+    nn = int(c.parameters['nparticles']**.5)
+    pos = np.zeros((nn, nn, 3), dtype = np.float64)
+    pos[:, :, 0] = np.linspace(0, 2*np.pi, nn)[None, :]
+    pos[:, :, 2] = np.linspace(0, 2*np.pi, nn)[:, None]
+    pos[:, :, 1] = np.random.random()*2*np.pi
+    c.generate_vector_field(write_to_file = True,
+                            spectra_slope = 1.)
+    c.generate_tracer_state(
+            species = 0,
+            write_to_file = False,
+            data = pos.reshape(-1, 3))
+    c.generate_tracer_state(
+            species = 1,
+            write_to_file = False,
+            data = pos.reshape(-1, 3))
+    c.set_host_info({'type' : 'pc'})
+    if opt.run:
+        c.run(ncpu = opt.ncpu)
+    df = c.get_particle_file()
+    fig = plt.figure(figsize=(10,5))
+    a = fig.add_subplot(121)
+    a.contour(
+            df['tracers0/state'][0, :, 0].reshape(nn, nn),
+            df['tracers0/state'][0, :, 2].reshape(nn, nn),
+            df['tracers0/velocity'][1, :, 0].reshape(nn, nn))
+    a = fig.add_subplot(122)
+    a.contour(
+            df['tracers1/state'][0, :, 0].reshape(nn, nn),
+            df['tracers1/state'][0, :, 2].reshape(nn, nn),
+            df['tracers1/velocity'][1, :, 0].reshape(nn, nn))
+    fig.savefig('interp.pdf')
+