diff --git a/LDDsimulation/LDDsimulation.py b/LDDsimulation/LDDsimulation.py
index 6da7a40315bcffead18618784fc3fc4e191a768d..6208b6c48545e2fc3aca0e120c52925bfda3662f 100644
--- a/LDDsimulation/LDDsimulation.py
+++ b/LDDsimulation/LDDsimulation.py
@@ -56,7 +56,7 @@ class LDDsimulation(object):
         # df.parameters["refinement_algorithm"] = "plaza_with_parent_facets"
         df.parameters["form_compiler"]["quadrature_degree"] = 12
         # interpolation degree, for source terms, intitial and boundary conditions.
-        self.interpolation_degree = 8
+        self.interpolation_degree = 4
         # # To be able to run DG in parallel
         # df.parameters["ghost_mode"] = "shared_facet"
         # df.parameters["ghost_mode"] = "none"
@@ -411,6 +411,12 @@ class LDDsimulation(object):
         # df.info(colored("start post processing calculations ...\n", "yellow"))
         # self.post_processing()
         # df.info(colored("finished post processing calculations \nAll right. I'm Done.", "green"))
+        for subdomain_index, subdomain_output in self.output.items():
+            print(f"Errornorms on subdomain{subdomain_index}")
+            for phase, different_errornorms in subdomain_output['errornorm'].items():
+                print(f"phase: {phase}")
+                for errortype, error in different_errornorms.items():
+                    print(f"{errortype}: {error}\n")
         return self.output
 
 
@@ -710,14 +716,34 @@ class LDDsimulation(object):
             # if we have an exact solution, write out several errors and
             # errornorms to be used later in paraview or latex plots.
             if subdomain.pressure_exact is not None:
+                pressure_exact = dict()
                 for phase in subdomain.has_phases:
                     pa_exact = subdomain.pressure_exact[phase]
                     pa_exact.t = self.t
-                    error_calculated = df.errornorm(pa_exact, subdomain.pressure[phase], 'L2', degree_rise=6)
+                    error_calculated = df.errornorm(pa_exact, subdomain.pressure[phase], 'L2', degree_rise=2)
+                    pressure_exact.update(
+                        {phase: df.interpolate(pa_exact, subdomain.function_space["pressure"][phase])}
+                        )
+                    absolute_difference = df.Function(subdomain.function_space["pressure"][phase])
+                    pressure_difference = pressure_exact[phase].vector()[:] - subdomain.pressure[phase].vector()[:]
+                    abs_diff_tmp = np.fabs(pressure_difference)
+                    absolute_difference.vector()[:] = abs_diff_tmp
+                    dx = subdomain.dx
+                    error_calculated_L1 = df.assemble(absolute_difference*dx)
+                    error_calculated_L2 = np.sqrt(df.assemble(absolute_difference**2*dx))
+                    error_calculated_L2_2 = df.norm(absolute_difference, norm_type='L2', mesh=subdomain.mesh)
+                    print(f"Errornorm dolfin: {error_calculated}")
+                    print(f"Errornorm manually calculated L1: {error_calculated_L1}")
+                    print(f"Errornorm manually calculated L2: {error_calculated_L2}")
+                    print(f"Errornorm manually calculated L2 with df.norm: {error_calculated_L2_2}")
                     self.output[subdom_ind]['errornorm'][phase]['L1'] += self.timestep_size*error_calculated
                     self.output[subdom_ind]['errornorm'][phase]['L2'] += self.timestep_size*error_calculated**2
+                    print(f"Linf error on subdomain {subdom_ind} and phase {phase} before checking: {self.output[subdom_ind]['errornorm'][phase]['Linf']}")
                     if error_calculated > self.output[subdom_ind]['errornorm'][phase]['Linf']:
-                        self.output[subdom_ind]['errornorm'][phase]['Linf'] = error_calculated
+                        self.output[subdom_ind]['errornorm'][phase].update(
+                            {'Linf': error_calculated}
+                            )
+                        print(f"Linf error on subdomain {subdom_ind} and phase {phase} after checking: {self.output[subdom_ind]['errornorm'][phase]['Linf']}")
 
                     # if we are at a timestep at which to write shit out,
                     # calculate the relative errornorm
@@ -868,20 +894,33 @@ class LDDsimulation(object):
         """
         evaluate the exact solution of the simulation (in case there is one) at
         all timesteps and write it to the solution file.
+        In addition write calculate and write out the saturation as well as the
+        source terms in order to montior the examples
         """
         # print(f" solution will be printed at times t = {self.timesteps_to_plot}\n")
         for subdom_ind, subdomain in self.subdomain.items():
             file = self.solution_file[subdom_ind]
             for timestep in self.timesteps_to_plot:
                 exact_pressure = dict()
+                S = self.saturation[subdom_ind]
+                saturation_w = df.Function(subdomain.function_space["pressure"]['wetting'])
+                saturation_nw = df.Function(subdomain.function_space["pressure"]['wetting'])
+                source = dict()
                 for phase in subdomain.has_phases:
+                    f_expr = subdomain.source[phase]
                     pa_exact = subdomain.pressure_exact[phase]
                     pa_exact.t = timestep
+                    f_expr.t = timestep
                     exact_pressure.update(
-                        {phase: df.interpolate(pa_exact, subdomain.function_space["pressure"][phase])}
+                        {phase: df.project(pa_exact, subdomain.function_space["pressure"][phase])}
                         )
+                    source.update(
+                        {phase: df.project(f_expr, subdomain.function_space["pressure"][phase])}
+                    )
                     exact_pressure[phase].rename("exact_pressure_"+"{}".format(phase), "exact_pressure_"+"{}".format(phase))
                     file.write(exact_pressure[phase], timestep)
+                    source[phase].rename("source_"+"{}".format(phase), "source_"+"{}".format(phase))
+                    file.write(source[phase], timestep)
 
                 exact_capillary_pressure = df.Function(subdomain.function_space["pressure"]['wetting'])
                 if subdomain.isRichards:
@@ -891,6 +930,15 @@ class LDDsimulation(object):
                     exact_capillary_pressure.vector().set_local(pc_temp)
                 exact_capillary_pressure.rename("pc_exact", "pc_exact")
                 file.write(exact_capillary_pressure, timestep)
+                saturation_w = df.project(S(exact_capillary_pressure), subdomain.function_space["pressure"]["wetting"])
+                # saturation_w.assign(Sat_w)
+                saturation_w.rename("Sw", "Sw")
+                file.write(saturation_w, timestep)
+                # S_nw = 1-S(exact_capillary_pressure).vector().get_local()
+                saturation_nw = df.project(1-S(exact_capillary_pressure), subdomain.function_space["pressure"]["wetting"])
+                # saturation_nw.assign(S_nw)
+                saturation_nw.rename("Snw", "Snw")
+                file.write(saturation_nw, timestep)
 
 
     def write_subsequent_errors_to_csv(self,#
@@ -1390,6 +1438,7 @@ class LDDsimulation(object):
         # in case time == self.starttime, the expression has already been
         # assembled by self._init_DirichletBC_dictionary.
         if np.fabs(time - self.starttime) < self.tol:
+            print("warning: update_DirichletBC_dictionary tried to update initial time")
             pass
         else:
             V = subdomain.function_space["pressure"]
diff --git a/TP-one-patch/mesh_study/R-one-patch-mesh-study-alternative.py b/TP-one-patch/mesh_study/R-one-patch-mesh-study-alternative.py
new file mode 100755
index 0000000000000000000000000000000000000000..825595390f4b32d71239cbf6439c8f01ea3f35ea
--- /dev/null
+++ b/TP-one-patch/mesh_study/R-one-patch-mesh-study-alternative.py
@@ -0,0 +1,491 @@
+#!/usr/bin/python3
+import dolfin as df
+import mshr
+import numpy as np
+import sympy as sym
+import typing as tp
+import domainPatch as dp
+import LDDsimulation as ldd
+import functools as ft
+import helpers as hlp
+import datetime
+import os
+import pandas as pd
+
+date = datetime.datetime.now()
+datestr = date.strftime("%Y-%m-%d")
+#import ufl as ufl
+
+# init sympy session
+sym.init_printing()
+
+use_case = "R-one-patch-mesh-study"
+# solver_tol = 5E-9
+max_iter_num = 1000
+FEM_Lagrange_degree = 1
+mesh_study = True
+# resolutions = {128: 1e-7} #[1,2,3,4,5,10,20,40,75,100]
+resolutions = {
+                # 1: 1e-7,
+                # 2: 1e-7,
+                # 4: 1e-7,
+                # 8: 1e-7,
+                # 16: 1e-7,
+                32: 1e-7,
+                # 64: 1e-7,
+                # 128: 1e-7,
+                # 256: 1e-7,
+                # 512: 1e-7,
+                }
+
+############ GRID #######################
+# mesh_resolution = 20
+timestep_size = 0.001
+number_of_timesteps = 10
+plot_timestep_every = 1
+# decide how many timesteps you want analysed. Analysed means, that we write out
+# subsequent errors of the L-iteration within the timestep.
+number_of_timesteps_to_analyse = 5
+starttimes = [0.5]
+# starttimes = [0.0, 0.05]
+
+# starttimes = {
+#     1: 0.0
+#     2: 0.05
+#     4: 0.1
+#     8: 0.2
+#     16: 0.4
+#     32: 0.7
+#     64: 1.0
+#     128: 1.3
+# }
+
+Lw = 0.5 #/timestep_size
+Lnw=Lw
+
+lambda_w = 0
+lambda_nw = 0
+
+include_gravity = False
+debugflag = False
+analyse_condition = True
+
+if mesh_study:
+    output_string = "./output/{}-{}_timesteps{}_P{}".format(datestr, use_case, number_of_timesteps, FEM_Lagrange_degree)
+else:
+    for tol in resolutions.values():
+        solver_tol = tol
+    output_string = "./output/{}-{}_timesteps{}_P{}_solver_tol{}".format(datestr, use_case, number_of_timesteps, FEM_Lagrange_degree, solver_tol)
+
+# toggle what should be written to files
+if mesh_study:
+    write_to_file = {
+        'space_errornorms': True,
+        'meshes_and_markers': True,
+        'L_iterations_per_timestep': True,
+        'solutions': True,
+        'absolute_differences': True,
+        'condition_numbers': analyse_condition,
+        'subsequent_errors': True
+    }
+else:
+    write_to_file = {
+        'space_errornorms': True,
+        'meshes_and_markers': True,
+        'L_iterations_per_timestep': False,
+        'solutions': True,
+        'absolute_differences': True,
+        'condition_numbers': analyse_condition,
+        'subsequent_errors': True
+    }
+
+##### Domain and Interface ####
+# global simulation domain domain
+sub_domain0_vertices = [df.Point(-1.0, -1.0),  #
+                        df.Point(1.0, -1.0),  #
+                        df.Point(1.0, 1.0),  #
+                        df.Point(-1.0, 1.0)]
+
+subdomain0_outer_boundary_verts = {
+    0: [sub_domain0_vertices[0],
+        sub_domain0_vertices[1],
+        sub_domain0_vertices[2],
+        sub_domain0_vertices[3],
+        sub_domain0_vertices[0]]
+}
+
+# list of subdomains given by the boundary polygon vertices.
+# Subdomains are given as a list of dolfin points forming
+# a closed polygon, such that mshr.Polygon(subdomain_def_points[i]) can be used
+# to create the subdomain. subdomain_def_points[0] contains the
+# vertices of the global simulation domain and subdomain_def_points[i] contains the
+# vertices of the subdomain i.
+subdomain_def_points = [sub_domain0_vertices]
+# in the below list, index 0 corresponds to the 12 interface which has index 1
+interface_def_points = None
+
+# if a subdomain has no outer boundary write None instead, i.e.
+# i: None
+# if i is the index of the inner subdomain.
+outer_boundary_def_points = {
+    # subdomain number
+    0 : subdomain0_outer_boundary_verts
+}
+
+# adjacent_subdomains[i] contains the indices of the subdomains sharing the
+# interface i (i.e. given by interface_def_points[i]).
+adjacent_subdomains = None
+isRichards = {
+    0: True, #
+    }
+
+viscosity = {#
+# subdom_num : viscosity
+    0 : {'wetting' :1,
+         'nonwetting': 1}, #
+}
+
+porosity = {#
+# subdom_num : porosity
+    0: 1,#
+}
+
+# Dict of the form: { subdom_num : density }
+densities = {
+    0: {'wetting': 1,  #997,
+        'nonwetting': 1}, #1225}
+}
+
+gravity_acceleration = 9.81
+
+L = {#
+# subdom_num : subdomain L for L-scheme
+    0: {'wetting' :Lw,
+         'nonwetting': Lnw},#
+}
+
+lambda_param = {#
+# subdom_num : lambda parameter for the L-scheme
+    0: {'wetting' :lambda_w,
+         'nonwetting': lambda_nw},#
+}
+
+## relative permeabilty functions on subdomain 1
+def rel_perm1w(s):
+    # relative permeabilty wetting on subdomain1
+    return s**2
+
+def rel_perm1nw(s):
+    # relative permeabilty nonwetting on subdomain1
+    return (1-s)**2
+
+_rel_perm1w = ft.partial(rel_perm1w)
+_rel_perm1nw = ft.partial(rel_perm1nw)
+
+subdomain1_rel_perm = {
+    'wetting': _rel_perm1w,#
+    'nonwetting': _rel_perm1nw
+}
+
+## dictionary of relative permeabilties on all domains.
+relative_permeability = {#
+    0: subdomain1_rel_perm,
+}
+
+# definition of the derivatives of the relative permeabilities
+# relative permeabilty functions on subdomain 1
+def rel_perm1w_prime(s):
+    # relative permeabilty on subdomain1
+    return 2*s
+
+def rel_perm1nw_prime(s):
+    # relative permeabilty on subdomain1
+    return -2*(1-s)
+
+_rel_perm1w_prime = ft.partial(rel_perm1w_prime)
+_rel_perm1nw_prime = ft.partial(rel_perm1nw_prime)
+
+subdomain1_rel_perm_prime = {
+    'wetting': _rel_perm1w_prime,
+    'nonwetting': _rel_perm1nw_prime
+}
+
+# dictionary of relative permeabilties on all domains.
+ka_prime = {
+    0: subdomain1_rel_perm_prime,
+}
+
+
+
+def saturation(pc, index):
+    # inverse capillary pressure-saturation-relationship
+    return df.conditional(pc > 0, 1/((1 + pc)**(1/(index + 1))), 1)
+
+def saturation_sym(pc, index):
+    # inverse capillary pressure-saturation-relationship
+    return 1/((1 + pc)**(1/(index + 1)))
+
+
+# derivative of S-pc relationship with respect to pc. This is needed for the
+# construction of a analytic solution.
+def saturation_sym_prime(pc, index):
+    # inverse capillary pressure-saturation-relationship
+    return -1/((index+1)*(1 + pc)**((index+2)/(index+1)))
+
+
+# def saturation(pc, index):
+#     # inverse capillary pressure-saturation-relationship
+#     return df.conditional(pc > 0, -index*pc, 1)
+#
+#
+# def saturation_sym(pc, index):
+#     # inverse capillary pressure-saturation-relationship
+#     return -index*pc
+#
+#
+# # derivative of S-pc relationship with respect to pc. This is needed for the
+# # construction of a analytic solution.
+# def saturation_sym_prime(pc, index):
+#     # inverse capillary pressure-saturation-relationship
+#     return -index
+
+
+# note that the conditional definition of S-pc in the nonsymbolic part will be
+# incorporated in the construction of the exact solution below.
+S_pc_sym = {
+    0: ft.partial(saturation_sym, index=1),
+}
+
+S_pc_sym_prime = {
+    0: ft.partial(saturation_sym_prime, index=1),
+}
+
+sat_pressure_relationship = {
+    0: ft.partial(saturation, index=1),
+}
+
+
+#############################################
+# Manufacture source expressions with sympy #
+#############################################
+x, y = sym.symbols('x[0], x[1]')  # needed by UFL
+t = sym.symbols('t', positive=True)
+
+epsilon_x_inner = 0.7
+epsilon_x_outer = 0.99
+epsilon_y_inner = epsilon_x_inner
+epsilon_y_outer = epsilon_x_outer
+
+def mollifier(x, epsilon):
+    """ one d mollifier """
+    out_expr = sym.exp(-1/(1-(x/epsilon)**2) + 1)
+    return out_expr
+
+mollifier_handle = ft.partial(mollifier, epsilon=epsilon_x_inner)
+
+pw_sym_x = sym.Piecewise(
+    (mollifier_handle(x), x**2 < epsilon_x_outer**2),
+    (0, True)
+)
+pw_sym_y = sym.Piecewise(
+    (mollifier_handle(y), y**2 < epsilon_y_outer**2),
+    (0, True)
+)
+
+def mollifier2d(x, y, epsilon):
+    """ one d mollifier """
+    out_expr = sym.exp(-1/(1-(x**2 + y**2)/epsilon**2) + 1)
+    return out_expr
+
+mollifier2d_handle = ft.partial(mollifier2d, epsilon=epsilon_x_outer)
+
+pw_sym2d_x = sym.Piecewise(
+    (mollifier2d_handle(x, y), x**2 + y**2 < epsilon_x_outer**2),
+    (0, True)
+)
+
+zero_on_epsilon_shrinking_of_subdomain = sym.Piecewise(
+    (mollifier_handle(sym.sqrt(x**2 + y**2)+2*epsilon_x_inner), ((-2*epsilon_x_inner<sym.sqrt(x**2 + y**2)) & (sym.sqrt(x**2 + y**2)<-epsilon_x_inner))),
+    (0, ((-epsilon_x_inner<=sym.sqrt(x**2 + y**2)) & (sym.sqrt(x**2 + y**2)<=epsilon_x_inner))),
+    (mollifier_handle(sym.sqrt(x**2 + y**2)-2*epsilon_x_inner), ((epsilon_x_inner<sym.sqrt(x**2 + y**2)) & (sym.sqrt(x**2 + y**2)<2*epsilon_x_inner))),
+    (1, True),
+)
+
+zero_on_epsilon_shrinking_of_subdomain_x = sym.Piecewise(
+    (mollifier_handle(x+2*epsilon_x_inner), ((-2*epsilon_x_inner<x) & (x<-epsilon_x_inner))),
+    (0, ((-epsilon_x_inner<=x) & (x<=epsilon_x_inner))),
+    (mollifier_handle(x-2*epsilon_x_inner), ((epsilon_x_inner<x) & (x<2*epsilon_x_inner))),
+    (1, True),
+)
+
+zero_on_epsilon_shrinking_of_subdomain_y = sym.Piecewise(
+    (1, y<=-2*epsilon_x_inner),
+    (mollifier_handle(y+2*epsilon_x_inner), ((-2*epsilon_x_inner<y) & (y<-epsilon_x_inner))),
+    (0, ((-epsilon_x_inner<=y) & (y<=epsilon_x_inner))),
+    (mollifier_handle(y-2*epsilon_x_inner), ((epsilon_x_inner<y) & (y<2*epsilon_x_inner))),
+    (1, True),
+)
+
+zero_on_shrinking = zero_on_epsilon_shrinking_of_subdomain #zero_on_epsilon_shrinking_of_subdomain_x + zero_on_epsilon_shrinking_of_subdomain_y
+gaussian = pw_sym2d_x# pw_sym_y*pw_sym_x
+cutoff = gaussian/(gaussian + zero_on_shrinking)
+
+# # construction of differentiable characteristic function.
+# def smooth_characteristic_func_on_epsilon_shrinking_of_subdomain0(x, y, epsilon_x_inner, epsilon_y_inner, epsilon_x_outer, epsilon_y_outer):
+#     dist_to_complement_x = ft.partial(mollifier, epsilon=epsilon_x_inner)
+#     dist_to_complement_y = ft.partial(mollifier, epsilon=epsilon_y_inner)
+#     dist_to_complement = dist_to_complement_y(y)*dist_to_complement_x(x)
+#     dist_to_eps_shrinking_x = ft.partial(zero_outside_epsilon_thickening_of_subdomain, epsilon=epsilon_x_outer)
+#     dist_to_eps_shrinking_y = ft.partial(zero_outside_epsilon_thickening_of_subdomain, epsilon=epsilon_y_outer)
+#     dist_to_eps_shrinking = dist_to_eps_shrinking_y(y)*dist_to_eps_shrinking_x(x)
+#     return dist_to_complement/(dist_to_eps_shrinking + dist_to_complement)
+#
+
+# def dist_to_epsilon_thickening_of_subdomain0_complement(x, y, epsilon):
+#     """ calculates the (euklidian distance)^2 of a point x,y to the epsilon
+#         thickening of the complement of the domain.
+#     """
+#     is_inside = ((1-sym.Abs(x) > epsilon) & (1-sym.Abs(y) > epsilon))
+#     sym.Piecewise((0, is_inside))
+
+p_e_sym = {
+    0: {'wetting': (-7 -1*t*(1 + x + y)),  #*cutoff,
+        'nonwetting': (-1 -1*t*(1.1+y + x))},  #*cutoff},
+}
+
+pc_e_sym = dict()
+for subdomain, isR in isRichards.items():
+    if isR:
+        pc_e_sym.update({subdomain: -p_e_sym[subdomain]['wetting']})
+    else:
+        pc_e_sym.update({subdomain: p_e_sym[subdomain]['nonwetting']
+                                        - p_e_sym[subdomain]['wetting']})
+
+
+symbols = {"x": x,
+           "y": y,
+           "t": t}
+# turn above symbolic code into exact solution for dolphin and
+# construct the rhs that matches the above exact solution.
+exact_solution_example = hlp.generate_exact_solution_expressions(
+                        symbols=symbols,
+                        isRichards=isRichards,
+                        symbolic_pressure=p_e_sym,
+                        symbolic_capillary_pressure=pc_e_sym,
+                        saturation_pressure_relationship=S_pc_sym,
+                        saturation_pressure_relationship_prime=S_pc_sym_prime,
+                        viscosity=viscosity,
+                        porosity=porosity,
+                        relative_permeability=relative_permeability,
+                        relative_permeability_prime=ka_prime,
+                        densities=densities,
+                        gravity_acceleration=gravity_acceleration,
+                        include_gravity=include_gravity,
+                        )
+source_expression = exact_solution_example['source']
+exact_solution = exact_solution_example['exact_solution']
+initial_condition = exact_solution_example['initial_condition']
+
+# Dictionary of dirichlet boundary conditions.
+dirichletBC = dict()
+# similarly to the outer boundary dictionary, if a patch has no outer boundary
+# None should be written instead of an expression.
+# This is a bit of a brainfuck:
+# dirichletBC[ind] gives a dictionary of the outer boundaries of subdomain ind.
+# Since a domain patch can have several disjoint outer boundary parts, the
+# expressions need to get an enumaration index which starts at 0.
+# So dirichletBC[ind][j] is the dictionary of outer dirichlet conditions of
+# subdomain ind and boundary part j.
+# Finally, dirichletBC[ind][j]['wetting'] and dirichletBC[ind][j]['nonwetting']
+# return the actual expression needed for the dirichlet condition for both
+# phases if present.
+
+# subdomain index: {outer boudary part index: {phase: expression}}
+for subdomain in isRichards.keys():
+    # if subdomain has no outer boundary, outer_boundary_def_points[subdomain] is None
+    if outer_boundary_def_points[subdomain] is None:
+        dirichletBC.update({subdomain: None})
+    else:
+        dirichletBC.update({subdomain: dict()})
+        # set the dirichlet conditions to be the same code as exact solution on
+        # the subdomain.
+        for outer_boundary_ind in outer_boundary_def_points[subdomain].keys():
+            dirichletBC[subdomain].update(
+                {outer_boundary_ind: exact_solution[subdomain]}
+                )
+
+
+# def saturation(pressure, subdomain_index):
+#     # inverse capillary pressure-saturation-relationship
+#     return df.conditional(pressure < 0, 1/((1 - pressure)**(1/(subdomain_index + 1))), 1)
+#
+# sa
+for starttime in starttimes:
+    for mesh_resolution, solver_tol in resolutions.items():
+        # initialise LDD simulation class
+        simulation = ldd.LDDsimulation(
+            tol=1E-14,
+            LDDsolver_tol=solver_tol,
+            debug=debugflag,
+            max_iter_num=max_iter_num,
+            FEM_Lagrange_degree=FEM_Lagrange_degree,
+            mesh_study=mesh_study
+            )
+
+        simulation.set_parameters(use_case=use_case,
+                                  output_dir=output_string,
+                                  subdomain_def_points=subdomain_def_points,
+                                  isRichards=isRichards,
+                                  interface_def_points=interface_def_points,
+                                  outer_boundary_def_points=outer_boundary_def_points,
+                                  adjacent_subdomains=adjacent_subdomains,
+                                  mesh_resolution=mesh_resolution,
+                                  viscosity=viscosity,
+                                  porosity=porosity,
+                                  L=L,
+                                  lambda_param=lambda_param,
+                                  relative_permeability=relative_permeability,
+                                  saturation=sat_pressure_relationship,
+                                  starttime=starttime,
+                                  number_of_timesteps=number_of_timesteps,
+                                  number_of_timesteps_to_analyse=number_of_timesteps_to_analyse,
+                                  plot_timestep_every=plot_timestep_every,
+                                  timestep_size=timestep_size,
+                                  sources=source_expression,
+                                  initial_conditions=initial_condition,
+                                  dirichletBC_expression_strings=dirichletBC,
+                                  exact_solution=exact_solution,
+                                  densities=densities,
+                                  include_gravity=include_gravity,
+                                  write2file=write_to_file,
+                                  )
+
+        simulation.initialise()
+        output_dir = simulation.output_dir
+        # simulation.write_exact_solution_to_xdmf()
+        output = simulation.run(analyse_condition=analyse_condition)
+        for subdomain_index, subdomain_output in output.items():
+            mesh_h = subdomain_output['mesh_size']
+            for phase, different_errornorms in subdomain_output['errornorm'].items():
+                filename = output_dir + "subdomain{}-space-time-errornorm-{}-phase.csv".format(subdomain_index, phase)
+                # for errortype, errornorm in different_errornorms.items():
+
+                    # eocfile = open("eoc_filename", "a")
+                    # eocfile.write( str(mesh_h) + " " + str(errornorm) + "\n" )
+                    # eocfile.close()
+                    # if subdomain.isRichards:mesh_h
+                data_dict = {
+                    'mesh_parameter': mesh_resolution,
+                    'mesh_h': mesh_h,
+                }
+                for error_type, errornorms in different_errornorms.items():
+                    data_dict.update(
+                        {error_type: errornorms}
+                    )
+                errors = pd.DataFrame(data_dict, index=[mesh_resolution])
+                # check if file exists
+                if os.path.isfile(filename) == True:
+                    with open(filename, 'a') as f:
+                        errors.to_csv(f, header=False, sep='\t', encoding='utf-8', index=False)
+                else:
+                    errors.to_csv(filename, sep='\t', encoding='utf-8', index=False)
diff --git a/TP-one-patch/mesh_study/R-one-patch-mesh-study.py b/TP-one-patch/mesh_study/R-one-patch-mesh-study.py
new file mode 100755
index 0000000000000000000000000000000000000000..fac5fc90a83b9b68f931327f258926feb7e38a29
--- /dev/null
+++ b/TP-one-patch/mesh_study/R-one-patch-mesh-study.py
@@ -0,0 +1,491 @@
+#!/usr/bin/python3
+import dolfin as df
+import mshr
+import numpy as np
+import sympy as sym
+import typing as tp
+import domainPatch as dp
+import LDDsimulation as ldd
+import functools as ft
+import helpers as hlp
+import datetime
+import os
+import pandas as pd
+
+date = datetime.datetime.now()
+datestr = date.strftime("%Y-%m-%d")
+#import ufl as ufl
+
+# init sympy session
+sym.init_printing()
+
+use_case = "R-one-patch-mesh-study"
+# solver_tol = 5E-9
+max_iter_num = 1000
+FEM_Lagrange_degree = 1
+mesh_study = True
+# resolutions = {128: 1e-7} #[1,2,3,4,5,10,20,40,75,100]
+resolutions = {
+                # 1: 1e-7,
+                # 2: 1e-7,
+                # 4: 1e-7,
+                # 8: 1e-7,
+                # 16: 1e-7,
+                32: 1e-7,
+                # 64: 1e-7,
+                # 128: 1e-7,
+                # 256: 1e-7,
+                # 512: 1e-7,
+                }
+
+############ GRID #######################
+# mesh_resolution = 20
+timestep_size = 0.00001
+number_of_timesteps = 10
+plot_timestep_every = 1
+# decide how many timesteps you want analysed. Analysed means, that we write out
+# subsequent errors of the L-iteration within the timestep.
+number_of_timesteps_to_analyse = 5
+starttimes = [0.5]
+# starttimes = [0.0, 0.05]
+
+# starttimes = {
+#     1: 0.0
+#     2: 0.05
+#     4: 0.1
+#     8: 0.2
+#     16: 0.4
+#     32: 0.7
+#     64: 1.0
+#     128: 1.3
+# }
+
+Lw = 0.025 #/timestep_size
+Lnw=Lw
+
+lambda_w = 0
+lambda_nw = 0
+
+include_gravity = False
+debugflag = False
+analyse_condition = True
+
+if mesh_study:
+    output_string = "./output/{}-{}_timesteps{}_P{}".format(datestr, use_case, number_of_timesteps, FEM_Lagrange_degree)
+else:
+    for tol in resolutions.values():
+        solver_tol = tol
+    output_string = "./output/{}-{}_timesteps{}_P{}_solver_tol{}".format(datestr, use_case, number_of_timesteps, FEM_Lagrange_degree, solver_tol)
+
+# toggle what should be written to files
+if mesh_study:
+    write_to_file = {
+        'space_errornorms': True,
+        'meshes_and_markers': True,
+        'L_iterations_per_timestep': True,
+        'solutions': True,
+        'absolute_differences': True,
+        'condition_numbers': analyse_condition,
+        'subsequent_errors': True
+    }
+else:
+    write_to_file = {
+        'space_errornorms': True,
+        'meshes_and_markers': True,
+        'L_iterations_per_timestep': False,
+        'solutions': True,
+        'absolute_differences': True,
+        'condition_numbers': analyse_condition,
+        'subsequent_errors': True
+    }
+
+##### Domain and Interface ####
+# global simulation domain domain
+sub_domain0_vertices = [df.Point(-1.0, -1.0),  #
+                        df.Point(1.0, -1.0),  #
+                        df.Point(1.0, 1.0),  #
+                        df.Point(-1.0, 1.0)]
+
+subdomain0_outer_boundary_verts = {
+    0: [sub_domain0_vertices[0],
+        sub_domain0_vertices[1],
+        sub_domain0_vertices[2],
+        sub_domain0_vertices[3],
+        sub_domain0_vertices[0]]
+}
+
+# list of subdomains given by the boundary polygon vertices.
+# Subdomains are given as a list of dolfin points forming
+# a closed polygon, such that mshr.Polygon(subdomain_def_points[i]) can be used
+# to create the subdomain. subdomain_def_points[0] contains the
+# vertices of the global simulation domain and subdomain_def_points[i] contains the
+# vertices of the subdomain i.
+subdomain_def_points = [sub_domain0_vertices]
+# in the below list, index 0 corresponds to the 12 interface which has index 1
+interface_def_points = None
+
+# if a subdomain has no outer boundary write None instead, i.e.
+# i: None
+# if i is the index of the inner subdomain.
+outer_boundary_def_points = {
+    # subdomain number
+    0 : subdomain0_outer_boundary_verts
+}
+
+# adjacent_subdomains[i] contains the indices of the subdomains sharing the
+# interface i (i.e. given by interface_def_points[i]).
+adjacent_subdomains = None
+isRichards = {
+    0: True, #
+    }
+
+viscosity = {#
+# subdom_num : viscosity
+    0 : {'wetting' :1,
+         'nonwetting': 1}, #
+}
+
+porosity = {#
+# subdom_num : porosity
+    0: 1,#
+}
+
+# Dict of the form: { subdom_num : density }
+densities = {
+    0: {'wetting': 1,  #997,
+        'nonwetting': 1}, #1225}
+}
+
+gravity_acceleration = 9.81
+
+L = {#
+# subdom_num : subdomain L for L-scheme
+    0: {'wetting' :Lw,
+         'nonwetting': Lnw},#
+}
+
+lambda_param = {#
+# subdom_num : lambda parameter for the L-scheme
+    0: {'wetting' :lambda_w,
+         'nonwetting': lambda_nw},#
+}
+
+## relative permeabilty functions on subdomain 1
+def rel_perm1w(s):
+    # relative permeabilty wetting on subdomain1
+    return s**2
+
+def rel_perm1nw(s):
+    # relative permeabilty nonwetting on subdomain1
+    return (1-s)**2
+
+_rel_perm1w = ft.partial(rel_perm1w)
+_rel_perm1nw = ft.partial(rel_perm1nw)
+
+subdomain1_rel_perm = {
+    'wetting': _rel_perm1w,#
+    'nonwetting': _rel_perm1nw
+}
+
+## dictionary of relative permeabilties on all domains.
+relative_permeability = {#
+    0: subdomain1_rel_perm,
+}
+
+# definition of the derivatives of the relative permeabilities
+# relative permeabilty functions on subdomain 1
+def rel_perm1w_prime(s):
+    # relative permeabilty on subdomain1
+    return 2*s
+
+def rel_perm1nw_prime(s):
+    # relative permeabilty on subdomain1
+    return -2*(1-s)
+
+_rel_perm1w_prime = ft.partial(rel_perm1w_prime)
+_rel_perm1nw_prime = ft.partial(rel_perm1nw_prime)
+
+subdomain1_rel_perm_prime = {
+    'wetting': _rel_perm1w_prime,
+    'nonwetting': _rel_perm1nw_prime
+}
+
+# dictionary of relative permeabilties on all domains.
+ka_prime = {
+    0: subdomain1_rel_perm_prime,
+}
+
+
+
+def saturation(pc, index):
+    # inverse capillary pressure-saturation-relationship
+    return df.conditional(pc > 0, 1/((1 + pc)**(1/(index + 1))), 1)
+
+def saturation_sym(pc, index):
+    # inverse capillary pressure-saturation-relationship
+    return 1/((1 + pc)**(1/(index + 1)))
+
+
+# derivative of S-pc relationship with respect to pc. This is needed for the
+# construction of a analytic solution.
+def saturation_sym_prime(pc, index):
+    # inverse capillary pressure-saturation-relationship
+    return -1/((index+1)*(1 + pc)**((index+2)/(index+1)))
+
+
+# def saturation(pc, index):
+#     # inverse capillary pressure-saturation-relationship
+#     return df.conditional(pc > 0, -index*pc, 1)
+#
+#
+# def saturation_sym(pc, index):
+#     # inverse capillary pressure-saturation-relationship
+#     return -index*pc
+#
+#
+# # derivative of S-pc relationship with respect to pc. This is needed for the
+# # construction of a analytic solution.
+# def saturation_sym_prime(pc, index):
+#     # inverse capillary pressure-saturation-relationship
+#     return -index
+
+
+# note that the conditional definition of S-pc in the nonsymbolic part will be
+# incorporated in the construction of the exact solution below.
+S_pc_sym = {
+    0: ft.partial(saturation_sym, index=1),
+}
+
+S_pc_sym_prime = {
+    0: ft.partial(saturation_sym_prime, index=1),
+}
+
+sat_pressure_relationship = {
+    0: ft.partial(saturation, index=1),
+}
+
+
+#############################################
+# Manufacture source expressions with sympy #
+#############################################
+x, y = sym.symbols('x[0], x[1]')  # needed by UFL
+t = sym.symbols('t', positive=True)
+
+epsilon_x_inner = 0.7
+epsilon_x_outer = 0.99
+epsilon_y_inner = epsilon_x_inner
+epsilon_y_outer = epsilon_x_outer
+
+def mollifier(x, epsilon):
+    """ one d mollifier """
+    out_expr = sym.exp(-1/(1-(x/epsilon)**2) + 1)
+    return out_expr
+
+mollifier_handle = ft.partial(mollifier, epsilon=epsilon_x_inner)
+
+pw_sym_x = sym.Piecewise(
+    (mollifier_handle(x), x**2 < epsilon_x_outer**2),
+    (0, True)
+)
+pw_sym_y = sym.Piecewise(
+    (mollifier_handle(y), y**2 < epsilon_y_outer**2),
+    (0, True)
+)
+
+def mollifier2d(x, y, epsilon):
+    """ one d mollifier """
+    out_expr = sym.exp(-1/(1-(x**2 + y**2)/epsilon**2) + 1)
+    return out_expr
+
+mollifier2d_handle = ft.partial(mollifier2d, epsilon=epsilon_x_outer)
+
+pw_sym2d_x = sym.Piecewise(
+    (mollifier2d_handle(x, y), x**2 + y**2 < epsilon_x_outer**2),
+    (0, True)
+)
+
+zero_on_epsilon_shrinking_of_subdomain = sym.Piecewise(
+    (mollifier_handle(sym.sqrt(x**2 + y**2)+2*epsilon_x_inner), ((-2*epsilon_x_inner<sym.sqrt(x**2 + y**2)) & (sym.sqrt(x**2 + y**2)<-epsilon_x_inner))),
+    (0, ((-epsilon_x_inner<=sym.sqrt(x**2 + y**2)) & (sym.sqrt(x**2 + y**2)<=epsilon_x_inner))),
+    (mollifier_handle(sym.sqrt(x**2 + y**2)-2*epsilon_x_inner), ((epsilon_x_inner<sym.sqrt(x**2 + y**2)) & (sym.sqrt(x**2 + y**2)<2*epsilon_x_inner))),
+    (1, True),
+)
+
+zero_on_epsilon_shrinking_of_subdomain_x = sym.Piecewise(
+    (mollifier_handle(x+2*epsilon_x_inner), ((-2*epsilon_x_inner<x) & (x<-epsilon_x_inner))),
+    (0, ((-epsilon_x_inner<=x) & (x<=epsilon_x_inner))),
+    (mollifier_handle(x-2*epsilon_x_inner), ((epsilon_x_inner<x) & (x<2*epsilon_x_inner))),
+    (1, True),
+)
+
+zero_on_epsilon_shrinking_of_subdomain_y = sym.Piecewise(
+    (1, y<=-2*epsilon_x_inner),
+    (mollifier_handle(y+2*epsilon_x_inner), ((-2*epsilon_x_inner<y) & (y<-epsilon_x_inner))),
+    (0, ((-epsilon_x_inner<=y) & (y<=epsilon_x_inner))),
+    (mollifier_handle(y-2*epsilon_x_inner), ((epsilon_x_inner<y) & (y<2*epsilon_x_inner))),
+    (1, True),
+)
+
+zero_on_shrinking = zero_on_epsilon_shrinking_of_subdomain #zero_on_epsilon_shrinking_of_subdomain_x + zero_on_epsilon_shrinking_of_subdomain_y
+gaussian = pw_sym2d_x# pw_sym_y*pw_sym_x
+cutoff = gaussian/(gaussian + zero_on_shrinking)
+
+# # construction of differentiable characteristic function.
+# def smooth_characteristic_func_on_epsilon_shrinking_of_subdomain0(x, y, epsilon_x_inner, epsilon_y_inner, epsilon_x_outer, epsilon_y_outer):
+#     dist_to_complement_x = ft.partial(mollifier, epsilon=epsilon_x_inner)
+#     dist_to_complement_y = ft.partial(mollifier, epsilon=epsilon_y_inner)
+#     dist_to_complement = dist_to_complement_y(y)*dist_to_complement_x(x)
+#     dist_to_eps_shrinking_x = ft.partial(zero_outside_epsilon_thickening_of_subdomain, epsilon=epsilon_x_outer)
+#     dist_to_eps_shrinking_y = ft.partial(zero_outside_epsilon_thickening_of_subdomain, epsilon=epsilon_y_outer)
+#     dist_to_eps_shrinking = dist_to_eps_shrinking_y(y)*dist_to_eps_shrinking_x(x)
+#     return dist_to_complement/(dist_to_eps_shrinking + dist_to_complement)
+#
+
+# def dist_to_epsilon_thickening_of_subdomain0_complement(x, y, epsilon):
+#     """ calculates the (euklidian distance)^2 of a point x,y to the epsilon
+#         thickening of the complement of the domain.
+#     """
+#     is_inside = ((1-sym.Abs(x) > epsilon) & (1-sym.Abs(y) > epsilon))
+#     sym.Piecewise((0, is_inside))
+
+p_e_sym = {
+    0: {'wetting': (-7 - (1+t*t)*(1 + x*x + y*y)),  #*cutoff,
+        'nonwetting': (-1 -t*(1.1+y + x**2))},  #*cutoff},
+}
+
+pc_e_sym = dict()
+for subdomain, isR in isRichards.items():
+    if isR:
+        pc_e_sym.update({subdomain: -p_e_sym[subdomain]['wetting']})
+    else:
+        pc_e_sym.update({subdomain: p_e_sym[subdomain]['nonwetting']
+                                        - p_e_sym[subdomain]['wetting']})
+
+
+symbols = {"x": x,
+           "y": y,
+           "t": t}
+# turn above symbolic code into exact solution for dolphin and
+# construct the rhs that matches the above exact solution.
+exact_solution_example = hlp.generate_exact_solution_expressions(
+                        symbols=symbols,
+                        isRichards=isRichards,
+                        symbolic_pressure=p_e_sym,
+                        symbolic_capillary_pressure=pc_e_sym,
+                        saturation_pressure_relationship=S_pc_sym,
+                        saturation_pressure_relationship_prime=S_pc_sym_prime,
+                        viscosity=viscosity,
+                        porosity=porosity,
+                        relative_permeability=relative_permeability,
+                        relative_permeability_prime=ka_prime,
+                        densities=densities,
+                        gravity_acceleration=gravity_acceleration,
+                        include_gravity=include_gravity,
+                        )
+source_expression = exact_solution_example['source']
+exact_solution = exact_solution_example['exact_solution']
+initial_condition = exact_solution_example['initial_condition']
+
+# Dictionary of dirichlet boundary conditions.
+dirichletBC = dict()
+# similarly to the outer boundary dictionary, if a patch has no outer boundary
+# None should be written instead of an expression.
+# This is a bit of a brainfuck:
+# dirichletBC[ind] gives a dictionary of the outer boundaries of subdomain ind.
+# Since a domain patch can have several disjoint outer boundary parts, the
+# expressions need to get an enumaration index which starts at 0.
+# So dirichletBC[ind][j] is the dictionary of outer dirichlet conditions of
+# subdomain ind and boundary part j.
+# Finally, dirichletBC[ind][j]['wetting'] and dirichletBC[ind][j]['nonwetting']
+# return the actual expression needed for the dirichlet condition for both
+# phases if present.
+
+# subdomain index: {outer boudary part index: {phase: expression}}
+for subdomain in isRichards.keys():
+    # if subdomain has no outer boundary, outer_boundary_def_points[subdomain] is None
+    if outer_boundary_def_points[subdomain] is None:
+        dirichletBC.update({subdomain: None})
+    else:
+        dirichletBC.update({subdomain: dict()})
+        # set the dirichlet conditions to be the same code as exact solution on
+        # the subdomain.
+        for outer_boundary_ind in outer_boundary_def_points[subdomain].keys():
+            dirichletBC[subdomain].update(
+                {outer_boundary_ind: exact_solution[subdomain]}
+                )
+
+
+# def saturation(pressure, subdomain_index):
+#     # inverse capillary pressure-saturation-relationship
+#     return df.conditional(pressure < 0, 1/((1 - pressure)**(1/(subdomain_index + 1))), 1)
+#
+# sa
+for starttime in starttimes:
+    for mesh_resolution, solver_tol in resolutions.items():
+        # initialise LDD simulation class
+        simulation = ldd.LDDsimulation(
+            tol=1E-14,
+            LDDsolver_tol=solver_tol,
+            debug=debugflag,
+            max_iter_num=max_iter_num,
+            FEM_Lagrange_degree=FEM_Lagrange_degree,
+            mesh_study=mesh_study
+            )
+
+        simulation.set_parameters(use_case=use_case,
+                                  output_dir=output_string,
+                                  subdomain_def_points=subdomain_def_points,
+                                  isRichards=isRichards,
+                                  interface_def_points=interface_def_points,
+                                  outer_boundary_def_points=outer_boundary_def_points,
+                                  adjacent_subdomains=adjacent_subdomains,
+                                  mesh_resolution=mesh_resolution,
+                                  viscosity=viscosity,
+                                  porosity=porosity,
+                                  L=L,
+                                  lambda_param=lambda_param,
+                                  relative_permeability=relative_permeability,
+                                  saturation=sat_pressure_relationship,
+                                  starttime=starttime,
+                                  number_of_timesteps=number_of_timesteps,
+                                  number_of_timesteps_to_analyse=number_of_timesteps_to_analyse,
+                                  plot_timestep_every=plot_timestep_every,
+                                  timestep_size=timestep_size,
+                                  sources=source_expression,
+                                  initial_conditions=initial_condition,
+                                  dirichletBC_expression_strings=dirichletBC,
+                                  exact_solution=exact_solution,
+                                  densities=densities,
+                                  include_gravity=include_gravity,
+                                  write2file=write_to_file,
+                                  )
+
+        simulation.initialise()
+        output_dir = simulation.output_dir
+        # simulation.write_exact_solution_to_xdmf()
+        output = simulation.run(analyse_condition=analyse_condition)
+        for subdomain_index, subdomain_output in output.items():
+            mesh_h = subdomain_output['mesh_size']
+            for phase, different_errornorms in subdomain_output['errornorm'].items():
+                filename = output_dir + "subdomain{}-space-time-errornorm-{}-phase.csv".format(subdomain_index, phase)
+                # for errortype, errornorm in different_errornorms.items():
+
+                    # eocfile = open("eoc_filename", "a")
+                    # eocfile.write( str(mesh_h) + " " + str(errornorm) + "\n" )
+                    # eocfile.close()
+                    # if subdomain.isRichards:mesh_h
+                data_dict = {
+                    'mesh_parameter': mesh_resolution,
+                    'mesh_h': mesh_h,
+                }
+                for error_type, errornorms in different_errornorms.items():
+                    data_dict.update(
+                        {error_type: errornorms}
+                    )
+                errors = pd.DataFrame(data_dict, index=[mesh_resolution])
+                # check if file exists
+                if os.path.isfile(filename) == True:
+                    with open(filename, 'a') as f:
+                        errors.to_csv(f, header=False, sep='\t', encoding='utf-8', index=False)
+                else:
+                    errors.to_csv(filename, sep='\t', encoding='utf-8', index=False)
diff --git a/TP-one-patch/mesh_study_for_fixed_timestep/R-one-patch-mesh-study-fixed-timestep.py b/TP-one-patch/mesh_study_for_fixed_timestep/R-one-patch-mesh-study-fixed-timestep.py
new file mode 100755
index 0000000000000000000000000000000000000000..14677c93cdbe98edb0217fbb0021084a48e7e232
--- /dev/null
+++ b/TP-one-patch/mesh_study_for_fixed_timestep/R-one-patch-mesh-study-fixed-timestep.py
@@ -0,0 +1,491 @@
+#!/usr/bin/python3
+import dolfin as df
+import mshr
+import numpy as np
+import sympy as sym
+import typing as tp
+import domainPatch as dp
+import LDDsimulation as ldd
+import functools as ft
+import helpers as hlp
+import datetime
+import os
+import pandas as pd
+
+date = datetime.datetime.now()
+datestr = date.strftime("%Y-%m-%d")
+#import ufl as ufl
+
+# init sympy session
+sym.init_printing()
+
+use_case = "R-one-patch-mesh-study-fixed-timestep-new-errornorm"
+# solver_tol = 5E-9
+max_iter_num = 1000
+FEM_Lagrange_degree = 1
+mesh_study = True
+# resolutions = {128: 1e-8} #[1,2,3,4,5,10,20,40,75,100]
+resolutions = {
+                1: 1e-8,
+                2: 1e-8,
+                4: 1e-8,
+                8: 1e-8,
+                16: 1e-8,
+                32: 1e-8,
+                64: 1e-8,
+                # 128: 1e-8,
+                # 256: 1e-8,
+                # 512: 1e-8,
+                }
+
+############ GRID #######################
+# mesh_resolution = 20
+timestep_size = 0.012
+number_of_timesteps = 1
+plot_timestep_every = 1
+# decide how many timesteps you want analysed. Analysed means, that we write out
+# subsequent errors of the L-iteration within the timestep.
+number_of_timesteps_to_analyse = 1
+starttimes = [0.0]
+# starttimes = [0.0, 0.05]
+
+# starttimes = {
+#     1: 0.0
+#     2: 0.05
+#     4: 0.1
+#     8: 0.2
+#     16: 0.4
+#     32: 0.7
+#     64: 1.0
+#     128: 1.3
+# }
+
+Lw = 0.025 #/timestep_size
+Lnw=Lw
+
+lambda_w = 0
+lambda_nw = 0
+
+include_gravity = False
+debugflag = True
+analyse_condition = False
+
+if mesh_study:
+    output_string = "./output/{}-{}_timesteps{}_P{}".format(datestr, use_case, number_of_timesteps, FEM_Lagrange_degree)
+else:
+    for tol in resolutions.values():
+        solver_tol = tol
+    output_string = "./output/{}-{}_timesteps{}_P{}_solver_tol{}".format(datestr, use_case, number_of_timesteps, FEM_Lagrange_degree, solver_tol)
+
+# toggle what should be written to files
+if mesh_study:
+    write_to_file = {
+        'space_errornorms': True,
+        'meshes_and_markers': True,
+        'L_iterations_per_timestep': True,
+        'solutions': True,
+        'absolute_differences': True,
+        'condition_numbers': analyse_condition,
+        'subsequent_errors': True
+    }
+else:
+    write_to_file = {
+        'space_errornorms': True,
+        'meshes_and_markers': True,
+        'L_iterations_per_timestep': False,
+        'solutions': True,
+        'absolute_differences': True,
+        'condition_numbers': analyse_condition,
+        'subsequent_errors': True
+    }
+
+##### Domain and Interface ####
+# global simulation domain domain
+sub_domain0_vertices = [df.Point(-1.0, -1.0),  #
+                        df.Point(1.0, -1.0),  #
+                        df.Point(1.0, 1.0),  #
+                        df.Point(-1.0, 1.0)]
+
+subdomain0_outer_boundary_verts = {
+    0: [sub_domain0_vertices[0],
+        sub_domain0_vertices[1],
+        sub_domain0_vertices[2],
+        sub_domain0_vertices[3],
+        sub_domain0_vertices[0]]
+}
+
+# list of subdomains given by the boundary polygon vertices.
+# Subdomains are given as a list of dolfin points forming
+# a closed polygon, such that mshr.Polygon(subdomain_def_points[i]) can be used
+# to create the subdomain. subdomain_def_points[0] contains the
+# vertices of the global simulation domain and subdomain_def_points[i] contains the
+# vertices of the subdomain i.
+subdomain_def_points = [sub_domain0_vertices]
+# in the below list, index 0 corresponds to the 12 interface which has index 1
+interface_def_points = None
+
+# if a subdomain has no outer boundary write None instead, i.e.
+# i: None
+# if i is the index of the inner subdomain.
+outer_boundary_def_points = {
+    # subdomain number
+    0 : subdomain0_outer_boundary_verts
+}
+
+# adjacent_subdomains[i] contains the indices of the subdomains sharing the
+# interface i (i.e. given by interface_def_points[i]).
+adjacent_subdomains = None
+isRichards = {
+    0: True, #
+    }
+
+viscosity = {#
+# subdom_num : viscosity
+    0 : {'wetting' :1,
+         'nonwetting': 1}, #
+}
+
+porosity = {#
+# subdom_num : porosity
+    0: 1,#
+}
+
+# Dict of the form: { subdom_num : density }
+densities = {
+    0: {'wetting': 1,  #997,
+        'nonwetting': 1}, #1225}
+}
+
+gravity_acceleration = 9.81
+
+L = {#
+# subdom_num : subdomain L for L-scheme
+    0: {'wetting' :Lw,
+         'nonwetting': Lnw},#
+}
+
+lambda_param = {#
+# subdom_num : lambda parameter for the L-scheme
+    0: {'wetting' :lambda_w,
+         'nonwetting': lambda_nw},#
+}
+
+## relative permeabilty functions on subdomain 1
+def rel_perm1w(s):
+    # relative permeabilty wetting on subdomain1
+    return s**2
+
+def rel_perm1nw(s):
+    # relative permeabilty nonwetting on subdomain1
+    return (1-s)**2
+
+_rel_perm1w = ft.partial(rel_perm1w)
+_rel_perm1nw = ft.partial(rel_perm1nw)
+
+subdomain1_rel_perm = {
+    'wetting': _rel_perm1w,#
+    'nonwetting': _rel_perm1nw
+}
+
+## dictionary of relative permeabilties on all domains.
+relative_permeability = {#
+    0: subdomain1_rel_perm,
+}
+
+# definition of the derivatives of the relative permeabilities
+# relative permeabilty functions on subdomain 1
+def rel_perm1w_prime(s):
+    # relative permeabilty on subdomain1
+    return 2*s
+
+def rel_perm1nw_prime(s):
+    # relative permeabilty on subdomain1
+    return -2*(1-s)
+
+_rel_perm1w_prime = ft.partial(rel_perm1w_prime)
+_rel_perm1nw_prime = ft.partial(rel_perm1nw_prime)
+
+subdomain1_rel_perm_prime = {
+    'wetting': _rel_perm1w_prime,
+    'nonwetting': _rel_perm1nw_prime
+}
+
+# dictionary of relative permeabilties on all domains.
+ka_prime = {
+    0: subdomain1_rel_perm_prime,
+}
+
+
+
+def saturation(pc, index):
+    # inverse capillary pressure-saturation-relationship
+    return df.conditional(pc > 0, 1/((1 + pc)**(1/(index + 1))), 1)
+
+def saturation_sym(pc, index):
+    # inverse capillary pressure-saturation-relationship
+    return 1/((1 + pc)**(1/(index + 1)))
+
+
+# derivative of S-pc relationship with respect to pc. This is needed for the
+# construction of a analytic solution.
+def saturation_sym_prime(pc, index):
+    # inverse capillary pressure-saturation-relationship
+    return -1/((index+1)*(1 + pc)**((index+2)/(index+1)))
+
+
+# def saturation(pc, index):
+#     # inverse capillary pressure-saturation-relationship
+#     return df.conditional(pc > 0, -index*pc, 1)
+#
+#
+# def saturation_sym(pc, index):
+#     # inverse capillary pressure-saturation-relationship
+#     return -index*pc
+#
+#
+# # derivative of S-pc relationship with respect to pc. This is needed for the
+# # construction of a analytic solution.
+# def saturation_sym_prime(pc, index):
+#     # inverse capillary pressure-saturation-relationship
+#     return -index
+
+
+# note that the conditional definition of S-pc in the nonsymbolic part will be
+# incorporated in the construction of the exact solution below.
+S_pc_sym = {
+    0: ft.partial(saturation_sym, index=1),
+}
+
+S_pc_sym_prime = {
+    0: ft.partial(saturation_sym_prime, index=1),
+}
+
+sat_pressure_relationship = {
+    0: ft.partial(saturation, index=1),
+}
+
+
+#############################################
+# Manufacture source expressions with sympy #
+#############################################
+x, y = sym.symbols('x[0], x[1]')  # needed by UFL
+t = sym.symbols('t', positive=True)
+
+epsilon_x_inner = 0.7
+epsilon_x_outer = 0.99
+epsilon_y_inner = epsilon_x_inner
+epsilon_y_outer = epsilon_x_outer
+
+def mollifier(x, epsilon):
+    """ one d mollifier """
+    out_expr = sym.exp(-1/(1-(x/epsilon)**2) + 1)
+    return out_expr
+
+mollifier_handle = ft.partial(mollifier, epsilon=epsilon_x_inner)
+
+pw_sym_x = sym.Piecewise(
+    (mollifier_handle(x), x**2 < epsilon_x_outer**2),
+    (0, True)
+)
+pw_sym_y = sym.Piecewise(
+    (mollifier_handle(y), y**2 < epsilon_y_outer**2),
+    (0, True)
+)
+
+def mollifier2d(x, y, epsilon):
+    """ one d mollifier """
+    out_expr = sym.exp(-1/(1-(x**2 + y**2)/epsilon**2) + 1)
+    return out_expr
+
+mollifier2d_handle = ft.partial(mollifier2d, epsilon=epsilon_x_outer)
+
+pw_sym2d_x = sym.Piecewise(
+    (mollifier2d_handle(x, y), x**2 + y**2 < epsilon_x_outer**2),
+    (0, True)
+)
+
+zero_on_epsilon_shrinking_of_subdomain = sym.Piecewise(
+    (mollifier_handle(sym.sqrt(x**2 + y**2)+2*epsilon_x_inner), ((-2*epsilon_x_inner<sym.sqrt(x**2 + y**2)) & (sym.sqrt(x**2 + y**2)<-epsilon_x_inner))),
+    (0, ((-epsilon_x_inner<=sym.sqrt(x**2 + y**2)) & (sym.sqrt(x**2 + y**2)<=epsilon_x_inner))),
+    (mollifier_handle(sym.sqrt(x**2 + y**2)-2*epsilon_x_inner), ((epsilon_x_inner<sym.sqrt(x**2 + y**2)) & (sym.sqrt(x**2 + y**2)<2*epsilon_x_inner))),
+    (1, True),
+)
+
+zero_on_epsilon_shrinking_of_subdomain_x = sym.Piecewise(
+    (mollifier_handle(x+2*epsilon_x_inner), ((-2*epsilon_x_inner<x) & (x<-epsilon_x_inner))),
+    (0, ((-epsilon_x_inner<=x) & (x<=epsilon_x_inner))),
+    (mollifier_handle(x-2*epsilon_x_inner), ((epsilon_x_inner<x) & (x<2*epsilon_x_inner))),
+    (1, True),
+)
+
+zero_on_epsilon_shrinking_of_subdomain_y = sym.Piecewise(
+    (1, y<=-2*epsilon_x_inner),
+    (mollifier_handle(y+2*epsilon_x_inner), ((-2*epsilon_x_inner<y) & (y<-epsilon_x_inner))),
+    (0, ((-epsilon_x_inner<=y) & (y<=epsilon_x_inner))),
+    (mollifier_handle(y-2*epsilon_x_inner), ((epsilon_x_inner<y) & (y<2*epsilon_x_inner))),
+    (1, True),
+)
+
+zero_on_shrinking = zero_on_epsilon_shrinking_of_subdomain #zero_on_epsilon_shrinking_of_subdomain_x + zero_on_epsilon_shrinking_of_subdomain_y
+gaussian = pw_sym2d_x# pw_sym_y*pw_sym_x
+cutoff = gaussian/(gaussian + zero_on_shrinking)
+
+# # construction of differentiable characteristic function.
+# def smooth_characteristic_func_on_epsilon_shrinking_of_subdomain0(x, y, epsilon_x_inner, epsilon_y_inner, epsilon_x_outer, epsilon_y_outer):
+#     dist_to_complement_x = ft.partial(mollifier, epsilon=epsilon_x_inner)
+#     dist_to_complement_y = ft.partial(mollifier, epsilon=epsilon_y_inner)
+#     dist_to_complement = dist_to_complement_y(y)*dist_to_complement_x(x)
+#     dist_to_eps_shrinking_x = ft.partial(zero_outside_epsilon_thickening_of_subdomain, epsilon=epsilon_x_outer)
+#     dist_to_eps_shrinking_y = ft.partial(zero_outside_epsilon_thickening_of_subdomain, epsilon=epsilon_y_outer)
+#     dist_to_eps_shrinking = dist_to_eps_shrinking_y(y)*dist_to_eps_shrinking_x(x)
+#     return dist_to_complement/(dist_to_eps_shrinking + dist_to_complement)
+#
+
+# def dist_to_epsilon_thickening_of_subdomain0_complement(x, y, epsilon):
+#     """ calculates the (euklidian distance)^2 of a point x,y to the epsilon
+#         thickening of the complement of the domain.
+#     """
+#     is_inside = ((1-sym.Abs(x) > epsilon) & (1-sym.Abs(y) > epsilon))
+#     sym.Piecewise((0, is_inside))
+
+p_e_sym = {
+    0: {'wetting': (-7 - (1+t*t)*(1 + x*x + y*y)),  #*cutoff,
+        'nonwetting': (-1 -t*(1.1+y + x**2))},  #*cutoff},
+}
+
+pc_e_sym = dict()
+for subdomain, isR in isRichards.items():
+    if isR:
+        pc_e_sym.update({subdomain: -p_e_sym[subdomain]['wetting']})
+    else:
+        pc_e_sym.update({subdomain: p_e_sym[subdomain]['nonwetting']
+                                        - p_e_sym[subdomain]['wetting']})
+
+
+symbols = {"x": x,
+           "y": y,
+           "t": t}
+# turn above symbolic code into exact solution for dolphin and
+# construct the rhs that matches the above exact solution.
+exact_solution_example = hlp.generate_exact_solution_expressions(
+                        symbols=symbols,
+                        isRichards=isRichards,
+                        symbolic_pressure=p_e_sym,
+                        symbolic_capillary_pressure=pc_e_sym,
+                        saturation_pressure_relationship=S_pc_sym,
+                        saturation_pressure_relationship_prime=S_pc_sym_prime,
+                        viscosity=viscosity,
+                        porosity=porosity,
+                        relative_permeability=relative_permeability,
+                        relative_permeability_prime=ka_prime,
+                        densities=densities,
+                        gravity_acceleration=gravity_acceleration,
+                        include_gravity=include_gravity,
+                        )
+source_expression = exact_solution_example['source']
+exact_solution = exact_solution_example['exact_solution']
+initial_condition = exact_solution_example['initial_condition']
+
+# Dictionary of dirichlet boundary conditions.
+dirichletBC = dict()
+# similarly to the outer boundary dictionary, if a patch has no outer boundary
+# None should be written instead of an expression.
+# This is a bit of a brainfuck:
+# dirichletBC[ind] gives a dictionary of the outer boundaries of subdomain ind.
+# Since a domain patch can have several disjoint outer boundary parts, the
+# expressions need to get an enumaration index which starts at 0.
+# So dirichletBC[ind][j] is the dictionary of outer dirichlet conditions of
+# subdomain ind and boundary part j.
+# Finally, dirichletBC[ind][j]['wetting'] and dirichletBC[ind][j]['nonwetting']
+# return the actual expression needed for the dirichlet condition for both
+# phases if present.
+
+# subdomain index: {outer boudary part index: {phase: expression}}
+for subdomain in isRichards.keys():
+    # if subdomain has no outer boundary, outer_boundary_def_points[subdomain] is None
+    if outer_boundary_def_points[subdomain] is None:
+        dirichletBC.update({subdomain: None})
+    else:
+        dirichletBC.update({subdomain: dict()})
+        # set the dirichlet conditions to be the same code as exact solution on
+        # the subdomain.
+        for outer_boundary_ind in outer_boundary_def_points[subdomain].keys():
+            dirichletBC[subdomain].update(
+                {outer_boundary_ind: exact_solution[subdomain]}
+                )
+
+
+# def saturation(pressure, subdomain_index):
+#     # inverse capillary pressure-saturation-relationship
+#     return df.conditional(pressure < 0, 1/((1 - pressure)**(1/(subdomain_index + 1))), 1)
+#
+# sa
+for starttime in starttimes:
+    for mesh_resolution, solver_tol in resolutions.items():
+        # initialise LDD simulation class
+        simulation = ldd.LDDsimulation(
+            tol=1E-14,
+            LDDsolver_tol=solver_tol,
+            debug=debugflag,
+            max_iter_num=max_iter_num,
+            FEM_Lagrange_degree=FEM_Lagrange_degree,
+            mesh_study=mesh_study
+            )
+
+        simulation.set_parameters(use_case=use_case,
+                                  output_dir=output_string,
+                                  subdomain_def_points=subdomain_def_points,
+                                  isRichards=isRichards,
+                                  interface_def_points=interface_def_points,
+                                  outer_boundary_def_points=outer_boundary_def_points,
+                                  adjacent_subdomains=adjacent_subdomains,
+                                  mesh_resolution=mesh_resolution,
+                                  viscosity=viscosity,
+                                  porosity=porosity,
+                                  L=L,
+                                  lambda_param=lambda_param,
+                                  relative_permeability=relative_permeability,
+                                  saturation=sat_pressure_relationship,
+                                  starttime=starttime,
+                                  number_of_timesteps=number_of_timesteps,
+                                  number_of_timesteps_to_analyse=number_of_timesteps_to_analyse,
+                                  plot_timestep_every=plot_timestep_every,
+                                  timestep_size=timestep_size,
+                                  sources=source_expression,
+                                  initial_conditions=initial_condition,
+                                  dirichletBC_expression_strings=dirichletBC,
+                                  exact_solution=exact_solution,
+                                  densities=densities,
+                                  include_gravity=include_gravity,
+                                  write2file=write_to_file,
+                                  )
+
+        simulation.initialise()
+        output_dir = simulation.output_dir
+        # simulation.write_exact_solution_to_xdmf()
+        output = simulation.run(analyse_condition=analyse_condition)
+        for subdomain_index, subdomain_output in output.items():
+            mesh_h = subdomain_output['mesh_size']
+            for phase, different_errornorms in subdomain_output['errornorm'].items():
+                filename = output_dir + "subdomain{}-space-time-errornorm-{}-phase.csv".format(subdomain_index, phase)
+                # for errortype, errornorm in different_errornorms.items():
+
+                    # eocfile = open("eoc_filename", "a")
+                    # eocfile.write( str(mesh_h) + " " + str(errornorm) + "\n" )
+                    # eocfile.close()
+                    # if subdomain.isRichards:mesh_h
+                data_dict = {
+                    'mesh_parameter': mesh_resolution,
+                    'mesh_h': mesh_h,
+                }
+                for error_type, errornorms in different_errornorms.items():
+                    data_dict.update(
+                        {error_type: errornorms}
+                    )
+                errors = pd.DataFrame(data_dict, index=[mesh_resolution])
+                # check if file exists
+                if os.path.isfile(filename) == True:
+                    with open(filename, 'a') as f:
+                        errors.to_csv(f, header=False, sep='\t', encoding='utf-8', index=False)
+                else:
+                    errors.to_csv(filename, sep='\t', encoding='utf-8', index=False)
diff --git a/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep-nonwetting0.py b/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep-nonwetting0.py
index 6135ce91eeb62e46c9a4b6377ce46f7b299dda38..f15efcf437c5a960dff1b9133ba6c4f36b30f844 100755
--- a/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep-nonwetting0.py
+++ b/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep-nonwetting0.py
@@ -35,7 +35,7 @@ resolutions = {
                 64: 1e-10,
                 128: 1e-10,
                 256: 1e-10,
-                512: 1e-10,
+                # 512: 1e-10,
                 }
 
 ############ GRID #######################
@@ -46,7 +46,8 @@ plot_timestep_every = 1
 # decide how many timesteps you want analysed. Analysed means, that we write out
 # subsequent errors of the L-iteration within the timestep.
 number_of_timesteps_to_analyse = 1
-starttimes = [0.0, 0.05, 0.1, 0.7, 1.3]
+# starttimes = [0.0, 0.05, 0.1, 0.7, 1.3]
+starttimes = [0.7]
 
 # starttimes = {
 #     1: 0.0
diff --git a/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep-wetting0.py b/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep-wetting0.py
index b97aa54e1c1ee3bd47f4f5d45e829f077961168a..9821788e1557ed8c15233d9efe9b1941cb129e7b 100755
--- a/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep-wetting0.py
+++ b/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep-wetting0.py
@@ -19,7 +19,7 @@ datestr = date.strftime("%Y-%m-%d")
 # init sympy session
 sym.init_printing()
 
-use_case = "TP-one-patch-mesh-study-fixed-timestep-wetting-constant"
+use_case = "TP-one-patch-mesh-study-fixed-timestep-wetting-constantexi"
 # solver_tol = 5E-9
 max_iter_num = 2000
 FEM_Lagrange_degree = 1
diff --git a/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep.py b/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep.py
index 6cd9a7c5eaa4e0e4400b533ad183bb7a9777978a..5c107d53980988da31daf5ae95107ec698232d42 100755
--- a/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep.py
+++ b/TP-one-patch/mesh_study_for_fixed_timestep/TP-one-patch-mesh-study-fixed-timestep.py
@@ -21,26 +21,26 @@ sym.init_printing()
 
 use_case = "TP-one-patch-mesh-study-fixed-timestep"
 # solver_tol = 5E-9
-max_iter_num = 2000
+max_iter_num = 1000
 FEM_Lagrange_degree = 1
 mesh_study = True
 # resolutions = {128: 1e-7} #[1,2,3,4,5,10,20,40,75,100]
 resolutions = {
-                1: 1e-10,
-                2: 1e-10,
-                4: 1e-10,
-                8: 1e-10,
-                16: 1e-10,
-                32: 1e-10,
-                64: 1e-10,
-                128: 1e-10,
-                256: 1e-10,
-                512: 1e-10,
+                1: 5e-7,
+                2: 5e-7,
+                4: 5e-7,
+                8: 5e-7,
+                16: 5e-7,
+                32: 5e-7,
+                64: 5e-7,
+                128: 5e-7,
+                # 256: 1e-10,
+                # 512: 1e-10,
                 }
 
 ############ GRID #######################
 # mesh_resolution = 20
-timestep_size = 0.01
+timestep_size = 0.001
 number_of_timesteps = 1
 plot_timestep_every = 1
 # decide how many timesteps you want analysed. Analysed means, that we write out
@@ -59,14 +59,14 @@ starttimes = [0.0, 0.05, 0.1, 0.7, 1.3]
 #     128: 1.3
 # }
 
-Lw = 0.05 #/timestep_size
+Lw = 0.025 #/timestep_size
 Lnw=Lw
 
 lambda_w = 0
 lambda_nw = 0
 
 include_gravity = False
-debugflag = True
+debugflag = False
 analyse_condition = False
 
 if mesh_study: