testing and docs

Author: pancetta

docs/source/projects/doc_fput.rst

@@ -0,0 +1,14 @@
+Full code: `pySDC/projects/Hamiltonian/fput.py <https://github.com/Parallel-in-Time/pySDC/blob/master/pySDC/projects/Hamiltonian/fput.py>`_
+
+.. literalinclude:: ../../../pySDC/projects/Hamiltonian/fput.py
+
+Results:
+
+.. literalinclude:: ../../../fput_out.txt
+
+.. image:: ../../../data/fput_hamiltonian.png
+   :scale: 100 %
+.. image:: ../../../data/fput_positions.png
+   :scale: 100 %
+.. image:: ../../../data/fput_energy.png
+   :scale: 100 %

pySDC/projects/Hamiltonian/README.rst

@@ -27,4 +27,14 @@ Coarsening can be done using only the sun for computing the acceleration.
 Note how PFASST works very well for the outer solar system problem, but not so well for the full solar system problem.
 Here, over 15 iterations are required in the mean, while SDC and MLSDC require only about 5 per step.
 
-.. include:: doc_solar_system.rst
+.. include:: doc_solar_system.rst
+
+Fermi-Pasta-Ulam-Tsingou problem
+--------------------------------
+
+This is the famous FPUT problem, one of the first numerical simulation done in physics.
+The basis for this setup can be found `here <http://www.scholarpedia.org/article/Fermi-Pasta-Ulam_nonlinear_lattice_oscillations>`_ and we implement this in the ``FermiPastaUlamTsingou`` problem class.
+Due to time limitations in the CI environment, we only run the first few steps and not until Tend=10000.
+Note that we run MLSDC here, since PFASST does not seem to converge easily.
+
+.. include:: doc_fput.rst

pySDC/projects/Hamiltonian/fput.py

@@ -34,7 +34,7 @@ def setup_fput():
     # initialize sweeper parameters
     sweeper_params = dict()
     sweeper_params['collocation_class'] = CollGaussLobatto
-    sweeper_params['num_nodes'] = [5]
+    sweeper_params['num_nodes'] = [5, 3]
     sweeper_params['spread'] = False
 
     # initialize problem parameters for the Penning trap
@@ -78,7 +78,9 @@ def run_simulation():
     description, controller_params = setup_fput()
     # set time parameters
     t0 = 0.0
-    Tend = 5000.0
+    # set this to 10000 to reproduce the picture in
+    # http://www.scholarpedia.org/article/Fermi-Pasta-Ulam_nonlinear_lattice_oscillations
+    Tend = 250.0
     num_procs = 1
 
     f = open('fput_out.txt', 'w')
@@ -126,12 +128,12 @@ def run_simulation():
 
     # get runtime
     timing_run = sort_stats(filter_stats(stats, type='timing_run'), sortby='time')[0][1]
-    out = '... took %s seconds to run this.' % timing_run
+    out = '... took %6.4f seconds to run this.' % timing_run
     f.write(out + '\n')
     print(out)
     f.close()
 
-    # assert np.mean(niters) <= maxmeaniter, 'Mean number of iterations is too high, got %s' % np.mean(niters)
+    assert np.mean(niters) <= 3.0, 'Mean number of iterations is too high, got %s' % np.mean(niters)
 
     fname = 'data/fput.dat'
     f = open(fname, 'wb')
@@ -176,7 +178,7 @@ def show_results(cwd=''):
         err_ham = ham[-1]
         plt_helper.plt.semilogy(time, ham, '-', lw=1, label='Iter ' + str(k))
     print(err_ham)
-    # assert err_ham < 7.5E-15, 'Error in the Hamiltonian is too large for %s, got %s' % (prob, err_ham)
+    assert err_ham < 1E-10, 'Error in the Hamiltonian is too large for %s, got %s' % (prob, err_ham)
 
     plt_helper.plt.xlabel('Time')
     plt_helper.plt.ylabel('Error in Hamiltonian')
@@ -197,7 +199,6 @@ def show_results(cwd=''):
     plt_helper.newfig(textwidth=238.96, scale=0.89)
 
     # Rearrange data for easy plotting
-
     for mode in result[0][1].keys():
         time = [item[0] for item in result]
         energy = [item[1][mode] for item in result]
@@ -246,5 +247,6 @@ def main():
     run_simulation()
     show_results()
 
+
 if __name__ == "__main__":
     main()

pySDC/tests/test_projects/test_hamiltonian/test_fput.py

@@ -0,0 +1,4 @@
+from pySDC.projects.Hamiltonian.fput import main
+
+def test_main():
+    main()