Skip to content
Snippets Groups Projects
Select Git revision
  • 14f373168079e3deac7586a38659ec335837a8dc
  • master default protected
  • parallelistation_of_subdomain_loop
  • parallelistation_test
  • nonzero_gli_term_for_nonwetting_in_TPR
  • testing_updating_pwi_as_pwiminus1_into_calculation_of_pnwi
  • v2.2
  • v2.1
  • v2.0
  • v1.0
10 results

TP-TP-2-patch-mesh-study.py

Blame
  • TP-TP-layered_soil_with_inner_patch.py 33.49 KiB
    #!/usr/bin/python3
    """TP-TP 2 patch soil simulation.
    
    This program sets up an LDD simulation
    """
    
    import dolfin as df
    import sympy as sym
    import functools as ft
    import LDDsimulation as ldd
    import helpers as hlp
    import datetime
    import os
    import pandas as pd
    
    # init sympy session
    sym.init_printing()
    
    # PREREQUISITS  ###############################################################
    # check if output directory "./output" exists. This will be used in
    # the generation of the output string.
    if not os.path.exists('./output'):
        os.mkdir('./output')
        print("Directory ", './output',  " created ")
    else:
        print("Directory ", './output',  " already exists. Will use as output \
        directory")
    
    date = datetime.datetime.now()
    datestr = date.strftime("%Y-%m-%d")
    
    # Name of the usecase that will be printed during simulation.
    use_case = "TP-TP-layered-soil-inner-patch-realistic"
    # The name of this very file. Needed for creating log output.
    thisfile = "TP-TP-layered_soil_with_inner_patch.py"
    
    # GENERAL SOLVER CONFIG  ######################################################
    # maximal iteration per timestep
    max_iter_num = 300
    FEM_Lagrange_degree = 1
    
    # GRID AND MESH STUDY SPECIFICATIONS  #########################################
    mesh_study = False
    resolutions = {
                    # 1: 1e-6,
                    # 2: 1e-6,
                    # 4: 1e-6,
                    # 8: 1e-6,
                    16: 5e-6,
                    # 32: 5e-6,
                    # 64: 2e-6,
                    # 128: 1e-6,
                    # 256: 1e-6,
                    }
    
    # starttimes gives a list of starttimes to run the simulation from.
    # The list is looped over and a simulation is run with t_0 as initial time
    #  for each element t_0 in starttimes.
    starttimes = [0.0]
    timestep_size = 0.001
    number_of_timesteps = 10
    
    # LDD scheme parameters  ######################################################
    Lw1 = 0.25  # /timestep_size
    Lnw1 = Lw1
    
    Lw2 = 0.25  # /timestep_size
    Lnw2 = Lw2
    
    Lw3 = 0.05  # /timestep_size
    Lnw3 = Lw3
    
    Lw4 = 0.05  # /timestep_size
    Lnw4 = Lw4
    
    Lw5 = 0.05  # /timestep_size
    Lnw5 = Lw5
    
    Lw6 = 0.05  # /timestep_size
    Lnw6 = Lw6
    
    lambda12_w = 40
    lambda12_nw = 40
    
    lambda23_w = 40
    lambda23_nw = 40
    
    lambda24_w = 40
    lambda24_nw= 40
    
    lambda25_w= 40
    lambda25_nw= 40
    
    lambda34_w = 40
    lambda34_nw = 40
    
    lambda36_w = 40
    lambda36_nw = 40
    
    lambda45_w = 40
    lambda45_nw = 40
    
    lambda46_w = 40
    lambda46_nw = 40
    
    lambda56_w = 40
    lambda56_nw = 40
    
    include_gravity = True
    debugflag = True
    analyse_condition = False
    
    # I/O CONFIG  #################################################################
    # when number_of_timesteps is high, it might take a long time to write all
    # timesteps to disk. Therefore, you can choose to only write data of every
    # plot_timestep_every timestep to disk.
    plot_timestep_every = 4
    # Decide how many timesteps you want analysed. Analysed means, that
    # subsequent errors of the L-iteration within the timestep are written out.
    number_of_timesteps_to_analyse = 5
    
    # fine grained control over data to be written to disk in the mesh study case
    # as well as for a regular simuation for a fixed grid.
    if mesh_study:
        write_to_file = {
            # output the relative errornorm (integration in space) w.r.t. an exact
            # solution for each timestep into a csv file.
            'space_errornorms': True,
            # save the mesh and marker functions to disk
            'meshes_and_markers': True,
            # save xdmf/h5 data for each LDD iteration for timesteps determined by
            # number_of_timesteps_to_analyse. I/O intensive!
            'L_iterations_per_timestep': False,
            # save solution to xdmf/h5.
            'solutions': True,
            # save absolute differences w.r.t an exact solution to xdmf/h5 file
            # to monitor where on the domains errors happen
            'absolute_differences': True,
            # analyise condition numbers for timesteps determined by
            # number_of_timesteps_to_analyse and save them over time to csv.
            'condition_numbers': analyse_condition,
            # output subsequent iteration errors measured in L^2  to csv for
            # timesteps determined by number_of_timesteps_to_analyse.
            # Usefull to monitor convergence of the acutal LDD solver.
            '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
        }
    
    # OUTPUT FILE STRING  #########################################################
    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
            )
    
    
    # DOMAIN AND INTERFACE  #######################################################
    # global domain
    subdomain0_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)]
    
    interface12_vertices = [df.Point(-1.0, 0.8),
                            df.Point(0.3, 0.8),
                            df.Point(0.5, 0.9),
                            df.Point(0.8, 0.7),
                            df.Point(1.0, 0.65)]
    
    
                            # interface23
    interface23_vertices = [df.Point(-1.0, 0.0),
                            df.Point(-0.35, 0.0),
                            # df.Point(6.5, 4.5),
                            df.Point(0.0, 0.0)]
    
    interface24_vertices = [interface23_vertices[2],
                            df.Point(0.6, 0.0),
                            ]
    
    interface25_vertices = [interface24_vertices[1],
                            df.Point(1.0, 0.0)
                            ]
    
    
    interface32_vertices = [interface23_vertices[2],
                            interface23_vertices[1],
                            interface23_vertices[0]]
    
    
    interface36_vertices = [df.Point(-1.0, -0.6),
                            df.Point(-0.6, -0.45)]
    
    
    interface46_vertices = [interface36_vertices[1],
                            df.Point(0.3, -0.25)]
    
    interface56_vertices = [interface46_vertices[1],
                            df.Point(0.65, -0.6),
                            df.Point(1.0, -0.7)]
    
    
    
    
    interface34_vertices = [interface36_vertices[1],
                            interface23_vertices[2]]
    # interface36
    
    interface45_vertices = [interface56_vertices[0],
                            df.Point(0.7, -0.2),
                            interface25_vertices[0]
                            ]
    
    
    # interface_vertices introduces a global numbering of interfaces.
    interface_def_points = [interface12_vertices,
                            interface23_vertices,
                            interface24_vertices,
                            interface25_vertices,
                            interface34_vertices,
                            interface36_vertices,
                            interface45_vertices,
                            interface46_vertices,
                            interface56_vertices,
                            ]
    
    adjacent_subdomains = [[1,2],
                           [2,3],
                           [2,4],
                           [2,5],
                           [3,4],
                           [3,6],
                           [4,5],
                           [4,6],
                           [5,6]
                           ]
    
    # subdomain1.
    subdomain1_vertices = [interface12_vertices[0],
                            interface12_vertices[1],
                            interface12_vertices[2],
                            interface12_vertices[3],
                            interface12_vertices[4],  # southern boundary, 12 interface
                            subdomain0_vertices[2],  # eastern boundary, outer boundary
                            subdomain0_vertices[3]]  # northern boundary, outer on_boundary
    
    # vertex coordinates of the outer boundaries. If it can not be specified as a
    # polygon, use an entry per boundary polygon.
    # This information is used for defining
    # the Dirichlet boundary conditions. If a domain is completely internal, the
    # dictionary entry should be 0: None
    subdomain1_outer_boundary_verts = {
        0: [subdomain1_vertices[4],
            subdomain1_vertices[5],  # eastern boundary, outer boundary
            subdomain1_vertices[6],
            subdomain1_vertices[0]]
    }
    
    #subdomain1
    subdomain2_vertices = [interface23_vertices[0],
                            interface23_vertices[1],
                            interface23_vertices[2],
                            interface24_vertices[1],
                            interface25_vertices[1],  # southern boundary, 23 interface
                            subdomain1_vertices[4],  # eastern boundary, outer boundary
                            subdomain1_vertices[3],
                            subdomain1_vertices[2],
                            subdomain1_vertices[1],
                            subdomain1_vertices[0] ]  # northern boundary, 12 interface
    
    subdomain2_outer_boundary_verts = {
        0: [subdomain2_vertices[9],
            subdomain2_vertices[0]],
        1: [subdomain2_vertices[4],
            subdomain2_vertices[5]]
    }
    
    
    subdomain3_vertices = [interface36_vertices[0],
                           interface36_vertices[1],
                           # interface34_vertices[0],
                           interface34_vertices[1],
                           # interface32_vertices[0],
                           interface32_vertices[1],
                           interface32_vertices[2]
                           ]
    
    subdomain3_outer_boundary_verts = {
        0: [subdomain3_vertices[4],
            subdomain3_vertices[0]]
    }
    
    
    # subdomain3
    subdomain4_vertices = [interface46_vertices[0],
                           interface46_vertices[1],
                           interface45_vertices[1],
                           interface24_vertices[1],
                           interface24_vertices[0],
                           interface34_vertices[1]
                           ]
    
    subdomain4_outer_boundary_verts = None
    
    subdomain5_vertices = [interface56_vertices[0],
                           interface56_vertices[1],
                           interface56_vertices[2],
                           interface25_vertices[1],
                           interface25_vertices[0],
                           interface45_vertices[1],
                           interface45_vertices[0]
    ]
    
    subdomain5_outer_boundary_verts = {
        0: [subdomain5_vertices[2],
            subdomain5_vertices[3]]
    }
    
    
    
    subdomain6_vertices = [subdomain0_vertices[0],
                           subdomain0_vertices[1], # southern boundary, outer boundary
                           interface56_vertices[2],
                           interface56_vertices[1],
                           interface56_vertices[0],
                           interface36_vertices[1],
                           interface36_vertices[0]
                           ]
    
    subdomain6_outer_boundary_verts = {
        0: [subdomain6_vertices[6],
            subdomain6_vertices[0],
            subdomain6_vertices[1],
            subdomain6_vertices[2]]
    }
    
    
    subdomain_def_points = [subdomain0_vertices,#
                          subdomain1_vertices,#
                          subdomain2_vertices,#
                          subdomain3_vertices,#
                          subdomain4_vertices,
                          subdomain5_vertices,
                          subdomain6_vertices
                          ]
    
    
    # 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
        1: subdomain1_outer_boundary_verts,
        2: subdomain2_outer_boundary_verts,
        3: subdomain3_outer_boundary_verts,
        4: subdomain4_outer_boundary_verts,
        5: subdomain5_outer_boundary_verts,
        6: subdomain6_outer_boundary_verts
    }
    
    # MODEL CONFIGURATION #########################################################
    
    isRichards = {
        1: False,
        2: False,
        3: False,
        4: False,
        5: False,
        6: False
        }
    
    
    # Dict of the form: { subdom_num : viscosity }
    viscosity = {
        1: {'wetting' :1.0,
             'nonwetting': 1/50},
        2: {'wetting' :1.0,
             'nonwetting': 1/50},
        3: {'wetting' :1.0,
             'nonwetting': 1/50},
        4: {'wetting' :1.0,
             'nonwetting': 1/50},
        5: {'wetting' :1.0,
             'nonwetting': 1/50},
        6: {'wetting' :1.0,
             'nonwetting': 1/50},
    }
    
    # Dict of the form: { subdom_num : density }
    densities = {
        1: {'wetting': 997.0,  #997
             'nonwetting': 1.225},  #1},  #1.225},
        2: {'wetting': 997.0,  #997
             'nonwetting': 1.225},  #1.225},
        3: {'wetting': 997.0,  #997
             'nonwetting': 1.225},  #1.225},
        4: {'wetting': 997.0,  #997
             'nonwetting': 1.225},  #1.225}
        5: {'wetting': 997.0,  #997
             'nonwetting': 1.225},  #1.225},
        6: {'wetting': 997.0,  #997
             'nonwetting': 1.225}  #1.225}
    }
    
    gravity_acceleration = 9.81
    # porosities taken from
    # https://www.geotechdata.info/parameter/soil-porosity.html
    # Dict of the form: { subdom_num : porosity }
    porosity = {
        1: 0.2,  #0.2,  # Clayey gravels, clayey sandy gravels
        2: 0.2,  #0.22, # Silty gravels, silty sandy gravels
        3: 0.2,  #0.37, # Clayey sands
        4: 0.2,  #0.2 # Silty or sandy clay
        5: 0.2,  #
        6: 0.2,  #
    }
    
    # subdom_num : subdomain L for L-scheme
    L = {
        1: {'wetting' :Lw1,
             'nonwetting': Lnw1},
        2: {'wetting' :Lw2,
             'nonwetting': Lnw2},
        3: {'wetting' :Lw3,
             'nonwetting': Lnw3},
        4: {'wetting' :Lw4,
             'nonwetting': Lnw4},
        5: {'wetting' :Lw5,
             'nonwetting': Lnw5},
        6: {'wetting' :Lw6,
             'nonwetting': Lnw6}
    }
    
    
    # interface_num : lambda parameter for the L-scheme on that interface.
    # Note that interfaces are numbered starting from 0, because
    # adjacent_subdomains is a list and not a dict. Historic fuckup, I know
    # We have defined above as interfaces
    # # interface_vertices introduces a global numbering of interfaces.
    # interface_def_points = [interface12_vertices,
    #                         interface23_vertices,
    #                         interface24_vertices,
    #                         interface25_vertices,
    #                         interface34_vertices,
    #                         interface36_vertices,
    #                         interface45_vertices,
    #                         interface46_vertices,
    #                         interface56_vertices,
    #                         ]
    lambda_param = {
        0: {'wetting': lambda12_w,
             'nonwetting': lambda12_nw},#
        1: {'wetting': lambda23_w,
             'nonwetting': lambda23_nw},#
        2: {'wetting': lambda24_w,
             'nonwetting': lambda24_nw},#
        3: {'wetting': lambda25_w,
             'nonwetting': lambda25_nw},#
        4: {'wetting': lambda34_w,
             'nonwetting': lambda34_nw},#
        5: {'wetting': lambda36_w,
             'nonwetting': lambda36_nw},#
        6: {'wetting': lambda45_w,
             'nonwetting': lambda45_nw},#
        7: {'wetting': lambda46_w,
             'nonwetting': lambda46_nw},#
        8: {'wetting': lambda56_w,
             'nonwetting': lambda56_nw},#
    }
    
    
    # after Lewis, see pdf file
    intrinsic_permeability = {
        1: 0.01,  # sand
        2: 0.01,  # sand, there is a range
        3: 0.01,  #10e-2,  # clay has a range
        4: 0.01,  #10e-3
        5: 0.01,  #10e-2,  # clay has a range
        6: 0.01,  #10e-3
    }
    
    
    # relative permeabilty functions on subdomain 1
    def rel_perm1w(s):
        # relative permeabilty wetting on subdomain1
        return intrinsic_permeability[1]*s**2
    
    
    def rel_perm1nw(s):
        # relative permeabilty nonwetting on subdomain1
        return intrinsic_permeability[1]*(1-s)**2
    
    
    # relative permeabilty functions on subdomain 2
    def rel_perm2w(s):
        # relative permeabilty wetting on subdomain2
        return intrinsic_permeability[2]*s**2
    
    
    def rel_perm2nw(s):
        # relative permeabilty nonwetting on subdomain2
        return intrinsic_permeability[2]*(1-s)**2
    
    
    # relative permeabilty functions on subdomain 3
    def rel_perm3w(s):
        # relative permeabilty wetting on subdomain3
        return intrinsic_permeability[3]*s**3
    
    
    def rel_perm3nw(s):
        # relative permeabilty nonwetting on subdomain3
        return intrinsic_permeability[3]*(1-s)**3
    
    
    # relative permeabilty functions on subdomain 4
    def rel_perm4w(s):
        # relative permeabilty wetting on subdomain4
        return intrinsic_permeability[4]*s**3
    
    
    def rel_perm4nw(s):
        # relative permeabilty nonwetting on subdomain4
        return intrinsic_permeability[4]*(1-s)**3
    
    
    # relative permeabilty functions on subdomain 5
    def rel_perm5w(s):
        # relative permeabilty wetting on subdomain5
        return intrinsic_permeability[5]*s**3
    
    
    def rel_perm5nw(s):
        # relative permeabilty nonwetting on subdomain5
        return intrinsic_permeability[5]*(1-s)**3
    
    
    # relative permeabilty functions on subdomain 6
    def rel_perm6w(s):
        # relative permeabilty wetting on subdomain6
        return intrinsic_permeability[6]*s**3
    
    
    def rel_perm6nw(s):
        # relative permeabilty nonwetting on subdomain6
        return intrinsic_permeability[6]*(1-s)**3
    
    
    _rel_perm1w = ft.partial(rel_perm1w)
    _rel_perm1nw = ft.partial(rel_perm1nw)
    
    _rel_perm2w = ft.partial(rel_perm2w)
    _rel_perm2nw = ft.partial(rel_perm2nw)
    
    _rel_perm3w = ft.partial(rel_perm3w)
    _rel_perm3nw = ft.partial(rel_perm3nw)
    
    _rel_perm4w = ft.partial(rel_perm4w)
    _rel_perm4nw = ft.partial(rel_perm4nw)
    
    _rel_perm5w = ft.partial(rel_perm5w)
    _rel_perm5nw = ft.partial(rel_perm5nw)
    
    _rel_perm6w = ft.partial(rel_perm6w)
    _rel_perm6nw = ft.partial(rel_perm6nw)
    
    subdomain1_rel_perm = {
        'wetting': _rel_perm1w,
        'nonwetting': _rel_perm1nw
    }
    
    subdomain2_rel_perm = {
        'wetting': _rel_perm2w,
        'nonwetting': _rel_perm2nw
    }
    
    subdomain3_rel_perm = {
        'wetting': _rel_perm3w,
        'nonwetting': _rel_perm3nw
    }
    
    subdomain4_rel_perm = {
        'wetting': _rel_perm4w,
        'nonwetting': _rel_perm4nw
    }
    
    subdomain5_rel_perm = {
        'wetting': _rel_perm5w,
        'nonwetting': _rel_perm5nw
    }
    
    subdomain6_rel_perm = {
        'wetting': _rel_perm6w,
        'nonwetting': _rel_perm6nw
    }
    
    # dictionary of relative permeabilties on all domains.
    relative_permeability = {
        1: subdomain1_rel_perm,
        2: subdomain2_rel_perm,
        3: subdomain3_rel_perm,
        4: subdomain4_rel_perm,
        5: subdomain5_rel_perm,
        6: subdomain6_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 intrinsic_permeability[1]*2*s
    
    
    def rel_perm1nw_prime(s):
        # relative permeabilty on subdomain1
        return -1*intrinsic_permeability[1]*2*(1-s)
    
    
    def rel_perm2w_prime(s):
        # relative permeabilty on subdomain2
        return intrinsic_permeability[2]*2*s
    
    
    def rel_perm2nw_prime(s):
        # relative permeabilty on subdomain2
        return -1*intrinsic_permeability[2]*2*(1-s)
    
    
    # definition of the derivatives of the relative permeabilities
    # relative permeabilty functions on subdomain 3
    def rel_perm3w_prime(s):
        # relative permeabilty on subdomain3
        return intrinsic_permeability[3]*3*s**2
    
    
    def rel_perm3nw_prime(s):
        # relative permeabilty on subdomain3
        return -1*intrinsic_permeability[3]*3*(1-s)**2
    
    
    # definition of the derivatives of the relative permeabilities
    # relative permeabilty functions on subdomain 4
    def rel_perm4w_prime(s):
        # relative permeabilty on subdomain4
        return intrinsic_permeability[4]*3*s**2
    
    
    def rel_perm4nw_prime(s):
        # relative permeabilty on subdomain4
        return -1*intrinsic_permeability[4]*3*(1-s)**2
    
    
    # definition of the derivatives of the relative permeabilities
    # relative permeabilty functions on subdomain 5
    def rel_perm5w_prime(s):
        # relative permeabilty on subdomain5
        return intrinsic_permeability[5]*3*s**2
    
    
    def rel_perm5nw_prime(s):
        # relative permeabilty on subdomain5
        return -1*intrinsic_permeability[5]*3*(1-s)**2
    
    
    # definition of the derivatives of the relative permeabilities
    # relative permeabilty functions on subdomain 6
    def rel_perm6w_prime(s):
        # relative permeabilty on subdomain6
        return intrinsic_permeability[6]*3*s**2
    
    
    def rel_perm6nw_prime(s):
        # relative permeabilty on subdomain6
        return -1*intrinsic_permeability[6]*3*(1-s)**2
    
    
    _rel_perm1w_prime = ft.partial(rel_perm1w_prime)
    _rel_perm1nw_prime = ft.partial(rel_perm1nw_prime)
    _rel_perm2w_prime = ft.partial(rel_perm2w_prime)
    _rel_perm2nw_prime = ft.partial(rel_perm2nw_prime)
    _rel_perm3w_prime = ft.partial(rel_perm3w_prime)
    _rel_perm3nw_prime = ft.partial(rel_perm3nw_prime)
    _rel_perm4w_prime = ft.partial(rel_perm4w_prime)
    _rel_perm4nw_prime = ft.partial(rel_perm4nw_prime)
    _rel_perm5w_prime = ft.partial(rel_perm5w_prime)
    _rel_perm5nw_prime = ft.partial(rel_perm5nw_prime)
    _rel_perm6w_prime = ft.partial(rel_perm6w_prime)
    _rel_perm6nw_prime = ft.partial(rel_perm6nw_prime)
    
    subdomain1_rel_perm_prime = {
        'wetting': _rel_perm1w_prime,
        'nonwetting': _rel_perm1nw_prime
    }
    
    
    subdomain2_rel_perm_prime = {
        'wetting': _rel_perm2w_prime,
        'nonwetting': _rel_perm2nw_prime
    }
    
    subdomain3_rel_perm_prime = {
        'wetting': _rel_perm3w_prime,
        'nonwetting': _rel_perm3nw_prime
    }
    
    
    subdomain4_rel_perm_prime = {
        'wetting': _rel_perm4w_prime,
        'nonwetting': _rel_perm4nw_prime
    }
    
    subdomain5_rel_perm_prime = {
        'wetting': _rel_perm5w_prime,
        'nonwetting': _rel_perm5nw_prime
    }
    
    subdomain6_rel_perm_prime = {
        'wetting': _rel_perm6w_prime,
        'nonwetting': _rel_perm6nw_prime
    }
    
    
    # dictionary of relative permeabilties on all domains.
    ka_prime = {
        1: subdomain1_rel_perm_prime,
        2: subdomain2_rel_perm_prime,
        3: subdomain3_rel_perm_prime,
        4: subdomain4_rel_perm_prime,
        5: subdomain5_rel_perm_prime,
        6: subdomain6_rel_perm_prime,
    }
    
    
    
    # S-pc-relation ship. We use the van Genuchten approach, i.e.
    # pc = 1/alpha*(S^{-1/m} -1)^1/n, where we set alpha = 0, assume
    # m = 1-1/n (see Helmig) and assume that residual saturation is Sw
    # this function needs to be monotonically decreasing in the capillary pressure
    # pc.
    # Since in the richards case pc=-pw, this becomes as a function of pw a mono
    # tonically INCREASING function like in our Richards-Richards paper. However
    # since we unify the treatment in the code for Richards and two-phase, we need
    # the same requierment
    # for both cases, two-phase and Richards.
    # def saturation(pc, n_index, alpha):
    #     # inverse capillary pressure-saturation-relationship
    #     return df.conditional(pc > 0, 1/((1 + (alpha*pc)**n_index)**((n_index - 1)/n_index)), 1)
    #
    # # S-pc-relation ship. We use the van Genuchten approach, i.e. pc = 1/alpha*(S^{-1/m} -1)^1/n, where
    # # we set alpha = 0, assume m = 1-1/n (see Helmig) and assume that residual saturation is Sw
    # def saturation_sym(pc, n_index, alpha):
    #     # inverse capillary pressure-saturation-relationship
    #     #df.conditional(pc > 0,
    #     return 1/((1 + (alpha*pc)**n_index)**((n_index - 1)/n_index))
    #
    #
    # # derivative of S-pc relationship with respect to pc. This is needed for the
    # # construction of a analytic solution.
    # def saturation_sym_prime(pc, n_index, alpha):
    #     # inverse capillary pressure-saturation-relationship
    #     return -(alpha*(n_index - 1)*(alpha*pc)**(n_index - 1)) / ( (1 + (alpha*pc)**n_index)**((2*n_index - 1)/n_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 = {
    #     1: ft.partial(saturation_sym, n_index=3, alpha=0.001),
    #     2: ft.partial(saturation_sym, n_index=3, alpha=0.001),
    #     3: ft.partial(saturation_sym, n_index=3, alpha=0.001),
    #     4: ft.partial(saturation_sym, n_index=3, alpha=0.001),
    #     5: ft.partial(saturation_sym, n_index=3, alpha=0.001),
    #     6: ft.partial(saturation_sym, n_index=3, alpha=0.001)
    # }
    #
    # S_pc_sym_prime = {
    #     1: ft.partial(saturation_sym_prime, n_index=3, alpha=0.001),
    #     2: ft.partial(saturation_sym_prime, n_index=3, alpha=0.001),
    #     3: ft.partial(saturation_sym_prime, n_index=3, alpha=0.001),
    #     4: ft.partial(saturation_sym_prime, n_index=3, alpha=0.001),
    #     5: ft.partial(saturation_sym_prime, n_index=3, alpha=0.001),
    #     6: ft.partial(saturation_sym_prime, n_index=3, alpha=0.001)
    # }
    #
    # sat_pressure_relationship = {
    #     1: ft.partial(saturation, n_index=3, alpha=0.001),
    #     2: ft.partial(saturation, n_index=3, alpha=0.001),
    #     3: ft.partial(saturation, n_index=3, alpha=0.001),
    #     4: ft.partial(saturation, n_index=3, alpha=0.001),
    #     5: ft.partial(saturation, n_index=3, alpha=0.001),
    #     6: ft.partial(saturation, n_index=3, alpha=0.001)
    # }
    
    def saturation(pc, n_index):
        # inverse capillary pressure-saturation-relationship
        return df.conditional(pc > 0, 1/((1 + pc)**(1/(n_index + 1))), 1)
    
    
    def saturation_sym(pc, n_index):
        # inverse capillary pressure-saturation-relationship
        return 1/((1 + pc)**(1/(n_index + 1)))
    
    
    def saturation_sym_prime(pc, n_index):
        # inverse capillary pressure-saturation-relationship
        return -1/((n_index+1)*(1 + pc)**((n_index+2)/(n_index+1)))
    
    
    S_pc_sym = {
        1: ft.partial(saturation_sym, n_index=1),
        2: ft.partial(saturation_sym, n_index=1),
        3: ft.partial(saturation_sym, n_index=2),
        4: ft.partial(saturation_sym, n_index=2),
        5: ft.partial(saturation_sym, n_index=2),
        6: ft.partial(saturation_sym, n_index=2)
    }
    
    S_pc_sym_prime = {
        1: ft.partial(saturation_sym_prime, n_index=1),
        2: ft.partial(saturation_sym_prime, n_index=1),
        3: ft.partial(saturation_sym_prime, n_index=2),
        4: ft.partial(saturation_sym_prime, n_index=2),
        5: ft.partial(saturation_sym_prime, n_index=2),
        6: ft.partial(saturation_sym_prime, n_index=2)
    }
    
    sat_pressure_relationship = {
        1: ft.partial(saturation, n_index=1),
        2: ft.partial(saturation, n_index=1),
        3: ft.partial(saturation, n_index=2),
        4: ft.partial(saturation, n_index=2),
        5: ft.partial(saturation, n_index=2),
        6: ft.partial(saturation, n_index=2)
    }
    
    
    ###############################################################################
    # Manufacture source expressions with sympy #
    ###############################################################################
    x, y = sym.symbols('x[0], x[1]')  # needed by UFL
    t = sym.symbols('t', positive=True)
    
    
    p_e_sym = {
            1: {'wetting': -6.0 - (1.0 + t*t)*(1.0 + x*x + y*y),
            'nonwetting': (-1 -t*(1.1 + y + x**2)) },
        2: {'wetting': -6.0 - (1.0 + t*t)*(1.0 + x*x + y*y),
            'nonwetting': (-1 -t*(1.1 + y + x**2)) },
        3: {'wetting': (-6.0 - (1.0 + t*t)*(1.0 + x*x)),
            'nonwetting': (-1 -t*(1.0 + x**2) - sym.sqrt(2+t**2)*(1+y)*y**2) },
        4: {'wetting': (-6.0 - (1.0 + t*t)*(1.0 + x*x)),
            'nonwetting': (-1 -t*(1.0 + x**2) - sym.sqrt(2+t**2)*(1+y)*y**2) },
        5: {'wetting': (-6.0 - (1.0 + t*t)*(1.0 + x*x)),
            'nonwetting': (-1 -t*(1.0 + x**2) - sym.sqrt(2+t**2)*(1+y)*y**2) },
        6: {'wetting': (-6.0 - (1.0 + t*t)*(1.0 + x*x)),
            'nonwetting': (-1 -t*(1.0 + x**2) - sym.sqrt(2+t**2)*(1+y)*y**2) },
        # 2: {'wetting': 1.0 - (1.0 + t*t)*(10.0 + x*x + (y-6.0)*(y-6.0)),
        #     'nonwetting': - 2 - t*(1.0 + (y-6.0) + x**2)**2 -sym.sqrt(2+t**2)*(1.0 + (y-6.0))},
        # 3: {'wetting': 1.0 - (1.0 + t*t)*(10.0 + x*x + (y-6.0)*(y-6.0)*3*sym.sin(-2*t+2*x)*sym.sin(1/2*y-1.2*t)),
        #     'nonwetting': - 2 - t*(1.0 + x**2)**2 -sym.sqrt(2+t**2)},
        # 4: {'wetting': 1.0 - (1.0 + t*t)*(10.0 + x*x + (y-6.0)*(y-6.0)*3*sym.sin(-2*t+2*x)*sym.sin(1/2*y-1.2*t)),
        #     'nonwetting': - 2 - t*(1.0 + x**2)**2 -sym.sqrt(2+t**2)}
    }
    
    
    pc_e_sym = dict()
    for subdomain, isR in isRichards.items():
        if isR:
            pc_e_sym.update({subdomain: -p_e_sym[subdomain]['wetting'].copy()})
        else:
            pc_e_sym.update({subdomain: p_e_sym[subdomain]['nonwetting'].copy()
                                            - p_e_sym[subdomain]['wetting'].copy()})
    
    
    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']
    
    # BOUNDARY CONDITIONS #########################################################
    # 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():
        # subdomain can have no outer boundary
        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]}
                    )
    
    
    # LOG FILE OUTPUT #############################################################
    # read this file and print it to std out. This way the simulation can produce a
    # log file with ./TP-R-layered_soil.py | tee simulation.log
    f = open(thisfile, 'r')
    print(f.read())
    f.close()
    
    
    # RUN #########################################################################
    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,
                gravity_acceleration=gravity_acceleration,
                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, error_dict in subdomain_output['errornorm'].items():
                    filename = output_dir \
                        + "subdomain{}".format(subdomain_index)\
                        + "-space-time-errornorm-{}-phase.csv".format(phase)
                    # for errortype, errornorm in error_dict.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 norm_type, errornorm in error_dict.items():
                        data_dict.update(
                            {norm_type: errornorm}
                        )
                    errors = pd.DataFrame(data_dict, index=[mesh_resolution])
                    # check if file exists
                    if os.path.isfile(filename) is 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
                            )