mfsimulation.py

"""mfsimulation module. contains the MFSimulation class."""

import errno
import sys
import inspect
import collections
import os.path
from ...mbase import run_model
from ..mfbase import PackageContainer, MFFileMgmt, ExtFileAction, \
    PackageContainerType, MFDataException, FlopyException, \
    VerbosityLevel
from ..mfpackage import MFPackage
from ..data.mfstructure import DatumType
from ..data import mfstructure
from ..utils import binaryfile_utils
from ..utils import mfobservation
from ..modflow import mfnam, mfims, mftdis, mfgwfgnc, mfgwfmvr
from ..data.mfdatautil import MFComment


class SimulationDict(collections.OrderedDict):
    """Class containing custom dictionary for MODFLOW simulations.

    Behaves as an OrderedDict with some additional features described below.

    Parameters
    ----------
    path : MFFileMgmt
        object containing path information for the simulation

    Methods
    -------
    find_in_path : (key_path : string, key_leaf : string) : MFData, int
        attempt to find key_leaf in a partial key path key_path
    output_keys : (print_keys : boolean) : list
        return a list of output data keys the dictionary supports for output
        data, print_keys allows those keys to be printed to output.
    input_keys : ()
        print all input data keys
    observation_keys : ()
        print observation keys
    keys : ()
        print all keys, input and output
    plot : (key : string, **kwargs)
        plot data with key 'key' using **kwargs for plot options
    shapefile : (key : string, **kwargs)
        create shapefile from data with key 'key' and with additional fields
        in **kwargs
    rename_all_packages : (name : string)
        rename all packages in the simulation and associated models

    """

    def __init__(self, path=None):
        """Define the __init__ method.

        Parameters:
            path (string): File-like path used as dictionary key

        """
        collections.OrderedDict.__init__(self)
        self._path = path

    def __getitem__(self, key):
        """Define the __getitem__ magic method.

        Parameters:
            key (string): Part or all of a dictionary key

        Returns:
            MFData or numpy.ndarray

        """
        if key == '_path' or not hasattr(self, '_path'):
            raise AttributeError(key)

        # FIX: Transport - Include transport output files
        if key[1] in ('CBC', 'HDS', 'DDN', 'UCN'):
            val = binaryfile_utils.MFOutput(self, self._path, key)
            return val.data

        elif key[-1] == 'Observations':
            val = mfobservation.MFObservation(self, self._path, key)
            return val.data

        if key in self:
            val = collections.OrderedDict.__getitem__(self, key)
            return val
        return AttributeError(key)

    def __setitem__(self, key, val):
        """Define the __setitem__ magic method.

        Parameters:
            key (string): Dictionary key
            val (MFData): MFData to store in dictionary

        """
        collections.OrderedDict.__setitem__(self, key, val)

    def find_in_path(self, key_path, key_leaf):
        """Attempt to find key_leaf in a partial key path key_path.

        Parameters:
            key_path (string): partial path to the data
            key_leaf (string): name of the data

        Returns:
            MFData: Data found at the path.
            int: Data index

        """
        key_path_size = len(key_path)
        for key, item in self.items():
            if key[:key_path_size] == key_path:
                if key[-1] == key_leaf:
                    # found key_leaf as a key in the dictionary
                    return item, None
                if not isinstance(item, MFComment):
                    data_item_index = 0
                    data_item_structures = item.structure.data_item_structures
                    for data_item_struct in data_item_structures:
                        if data_item_struct.name == key_leaf:
                            # found key_leaf as a data item name in the data in
                            # the dictionary
                            return item, data_item_index
                        if data_item_struct.type != DatumType.keyword:
                            data_item_index += 1
        return None, None

    def output_keys(self, print_keys=True):
        """Return a list of output data keys.

        Parameters:
            print_keys (bool): print keys to console

        Returns:
            list: keys for requesting binary output

        """
        # get keys to request binary output
        x = binaryfile_utils.MFOutputRequester.getkeys(self, self._path,
                                                       print_keys=print_keys)
        return [key for key in x.dataDict]

    def input_keys(self):
        """Return a list of input data keys.

        Returns:
            list: input data keys

        """
        # get keys to request input ie. package data
        for key in self:
            print(key)

    def observation_keys(self):
        """Return a list of observation keys.

        Returns:
            list: observation keys

        """
        # get keys to request observation file output
        mfobservation.MFObservationRequester.getkeys(self, self._path)

    def keys(self):
        """Return a list of all keys.

        Returns:
            list: all keys

        """
        # overrides the built in keys to print all keys, input and output
        self.input_keys()
        try:
            self.output_keys()
        except OSError as e:
            if e.errno == errno.EEXIST:
                pass
        try:
            self.observation_keys()
        except KeyError:
            pass


class MFSimulationData(object):
    """Class containing MODFLOW simulation data and file formatting data.

    Parameters
    ----------
    path : string
        path on disk to the simulation

    Attributes
    ----------
    indent_string : string
        string used to define how much indent to use (file formatting)
    internal_formatting : list
        list defining string to use for internal formatting
    external_formatting : list
        list defining string to use for external formatting
    open_close_formatting : list
        list defining string to use for open/close
    max_columns_of_data : int
        maximum columns of data before line wraps
    wrap_multidim_arrays : bool
        whether to wrap line for multi-dimensional arrays at the end of a
        row/column/layer
    float_precision : int
        number of decimal points to write for a floating point number
    float_characters : int
        number of characters a floating point number takes up
    sci_note_upper_thres : float
        numbers greater than this threshold are written in scientific notation
    sci_note_lower_thres : float
        numbers less than this threshold are written in scientific notation
    mfpath : MFFileMgmt
        file path location information for the simulation
    model_dimensions : OrderedDict
        dictionary containing discretization information for each model
    mfdata : SimulationDict
        custom dictionary containing all model data for the simulation

    """

    def __init__(self, path):
        """Define the __init__ method.

        Parameters:
            path (string): File-like path to simulation

        """
        # --- formatting variables ---
        self.indent_string = '  '
        self.constant_formatting = ['constant', '']
        self.max_columns_of_data = 20
        self.wrap_multidim_arrays = True
        self.float_precision = 8
        self.float_characters = 15
        self._sci_note_upper_thres = 100000
        self._sci_note_lower_thres = 0.001
        self.fast_write = True
        self.comments_on = False
        self.auto_set_sizes = True
        self.verify_data = True
        self.debug = False
        self.verbose = True
        self.verbosity_level = VerbosityLevel.normal

        self._update_str_format()

        # --- file path ---
        self.mfpath = MFFileMgmt(path)

        # --- ease of use variables to make working with modflow input and
        # output data easier --- model dimension class for each model
        self.model_dimensions = collections.OrderedDict()

        # --- model data ---
        self.mfdata = SimulationDict(self.mfpath)

        # --- temporary variables ---
        # other external files referenced
        self.referenced_files = collections.OrderedDict()

    def set_sci_note_upper_thres(self, value):
        """Set threshold number.

        Sets threshold number where any number larger than threshold
        is represented in scientific notation.

        Parameters:
            value (float): threshold value

        """
        self._sci_note_upper_thres = value
        self._update_str_format()

    def set_sci_note_lower_thres(self, value):
        """Set threshold number.

        Sets threshold number where any number smaller than threshold
        is represented in scientific notation.

        Parameters:
            value (float): threshold value

        """
        self._sci_note_lower_thres = value
        self._update_str_format()

    def _update_str_format(self):
        """Update floating point formatting strings."""
        self.reg_format_str = '{:.%dE}' % \
            self.float_precision
        self.sci_format_str = '{:%d.%df' \
                              '}' % (self.float_characters,
                                     self.float_precision)


class MFSimulation(PackageContainer):
    """Entry point into any MODFLOW simulation.

    MFSimulation is used to load, build, and/or save a MODFLOW6 simulation.

    Parameters
    ----------
    sim_name : string
        name of the simulation.
    version : string
        MODFLOW version
    exe_name : string
        relative path to MODFLOW executable from the simulation working folder
    sim_ws : string
        path to simulation working folder
    verbosity_level : int
        verbosity level of standard output
            0 : no standard output
            1 : standard error/warning messages with some informational
                messages
            2 : verbose mode with full error/warning/informational messages.
                this is ideal for debugging
    continue_ : bool
        sets the continue option in the simulation name file. the continue
        option is a keyword flag to indicate that the simulation should
        continue even if one or more solutions do not converge.
    nocheck : bool
         sets the nocheck option in the simulation name file. the nocheck
         option is a keyword flag to indicate that the model input check
         routines should not be called prior to each time step. checks
         are performed by default.
    memory_print_option : str
         sets memory_print_option in the simulation name file.
         memory_print_option is a flag that controls printing of detailed
         memory manager usage to the end of the simulation list file.  NONE
         means do not print detailed information. SUMMARY means print only
         the total memory for each simulation component. ALL means print
         information for each variable stored in the memory manager. NONE is
         default if memory_print_option is not specified.

    Attributes
    ----------
    sim_name : string
        name of the simulation
    _models : OrderedDict
        all models in the simulation
    _exchange_files : list
        all exchange packages in the simulation
    _ims_files : list
        all ims packages in the simulation
    name_file : MFPackage
        simulation name file
    _tdis_file
        simulation tdis file
    sim_package_list
        list of all "simulation level" packages

    Methods
    -------
    load : (sim_name : string, version : string, exe_name : string,
            sim_ws : string, strict : boolean,
            verbosity_level : VerbosityLevel) :
            MFSimulation
        a class method that loads a simulation from files
    write_simulation
        writes the simulation to files
    set_sim_path : (path : string)
        set the file path to the root simulation folder and updates all model
        file paths
    get_model : (model_name : string)
              : [MFModel]
        returns the models in the simulation with a given model name, name file
        name, or model type
    add_model : (model : MFModel, sln_group : integer)
        add model to the simulation
    remove_model : (model_name : string)
        remove model from the simulation
    get_package : (type : string)
        returns a simulation package based on package type
    add_package : (package : MFPackage)
        adds a simulation package to the simulation
    remove_package : (package_name : string)
        removes package from the simulation.  package_name can be the
        package's name, type, or package object to be removed from
        the model
    is_valid : () : boolean
        checks the validity of the solution and all of its models and packages
    set_all_data_external
        sets the simulation's list and array data to be stored externally

    Examples
    --------
    >>> s = MFSimulation.load('my simulation', 'simulation.nam')

    """

    def __init__(self, sim_name='sim', version='mf6', exe_name='mf6.exe',
                 sim_ws='.', verbosity_level=1, continue_=None,
                 nocheck=None, memory_print_option=None):
        """Initialization.

        __init__ is used to initialize a simulation object

        Parameters:
            sim_name : string
                name of the simulation.
            version : string
                MODFLOW version
            exe_name : string
                relative path to MODFLOW executable from the simulation
                working folder
            sim_ws : string
                path to simulation working folder
            verbosity_level : int
                verbosity level of standard output
                    0 : no standard output
                    1 : standard error/warning messages with some
                        informational messages
                    2 : verbose mode with full error/warning/informational
                        messages. this is ideal for debugging
            continue_ : bool
                sets the continue option in the simulation name file. the
                continue option is a keyword flag to indicate that the
                simulation should continue even if one or more solutions do
                not converge.
            nocheck : bool
                 sets the nocheck option in the simulation name file. the
                 nocheckoption is a keyword flag to indicate that the model
                 input check routines should not be called prior to each time
                 step. checks are performed by default.
            memory_print_option : str
                 sets memory_print_option in the simulation name file.
                 memory_print_option is a flag that controls printing of
                 detailed memory manager usage to the end of the simulation
                 list file.  NONE means do not print detailed information.
                 SUMMARY means print only the total memory for each
                 simulation component. ALL means print information for each
                 variable stored in the memory manager. NONE is default if
                 memory_print_option is not specified.

        """
        super(MFSimulation, self).__init__(MFSimulationData(sim_ws), sim_name)
        self.simulation_data.verbosity_level = self._resolve_verbosity_level(
            verbosity_level)
        # verify metadata
        fpdata = mfstructure.MFStructure()
        if not fpdata.valid:
            excpt_str = 'Invalid package metadata.  Unable to load MODFLOW ' \
                        'file structure metadata.'
            raise FlopyException(excpt_str)

        # initialize
        self.dimensions = None
        self.type = 'Simulation'

        self.version = version
        self.exe_name = exe_name
        self._models = collections.OrderedDict()
        self._tdis_file = None
        self._exchange_files = collections.OrderedDict()
        self._ims_files = collections.OrderedDict()
        self._ghost_node_files = {}
        self._mover_files = {}
        self._other_files = collections.OrderedDict()
        self.structure = fpdata.sim_struct
        self.model_type = None

        self._exg_file_num = {}
        self._gnc_file_num = 0
        self._mvr_file_num = 0

        self.simulation_data.mfpath.set_last_accessed_path()

        # build simulation name file
        self.name_file = mfnam.ModflowNam(
            self, filename='mfsim.nam', continue_=continue_, nocheck=nocheck,
            memory_print_option=memory_print_option)

        # try to build directory structure
        sim_path = self.simulation_data.mfpath.get_sim_path()
        if not os.path.isdir(sim_path):
            try:
                os.makedirs(sim_path)
            except OSError as e:
                if self.simulation_data.verbosity_level.value >= \
                        VerbosityLevel.quiet.value:
                    print('An error occurred when trying to create the '
                          'directory {}: {}'.format(sim_path, e.strerror))

        # set simulation validity initially to false since the user must first
        # add at least one model to the simulation and fill out the name and
        #  tdis files
        self.valid = False

    def __getattr__(self, item):
        """Override __getattr__ to allow retrieving models.

        __getattr__ is used to allow for getting models and packages as if
        they are attributes

        Parameters
        ----------
        item : str
            model or package name


        Returns
        -------
        md : Model or package object
            Model or package object of type :class:flopy6.mfmodel or
            :class:flopy6.mfpackage

        """
        if item == 'valid' or not hasattr(self, 'valid'):
            raise AttributeError(item)

        models = []
        if item in self.structure.model_types:
            # get all models of this type
            for model in self._models.values():
                if model.model_type == item:
                    models.append(model)

        if len(models) > 0:
            return models
        elif item in self._models:
            model = self.get_model(item)
            if model is not None:
                return model
            raise AttributeError(item)
        else:
            package = self.get_package(item)
            if package is not None:
                return package
            raise AttributeError(item)

    def __repr__(self):
        """Override __repr__ to print custom string.

        Returns:
            repr string : str
                string describing object

        """
        return self._get_data_str(True)

    def __str__(self):
        """Override __str__ to print custom string.

        Returns:
            str string : str
                string describing object

        """
        return self._get_data_str(False)

    def _get_data_str(self, formal):
        file_mgt = self.simulation_data.mfpath
        data_str = 'sim_name = {}\nsim_path = {}\nexe_name = ' \
                   '{}\n\n'.format(self.name, file_mgt.get_sim_path(),
                                   self.exe_name)

        for package in self._packagelist:
            pk_str = package._get_data_str(formal, False)
            if formal:
                if len(pk_str.strip()) > 0:
                    data_str = '{}###################\nPackage {}\n' \
                               '###################\n\n' \
                               '{}\n'.format(data_str, package._get_pname(),
                                             pk_str)
            else:
                if len(pk_str.strip()) > 0:
                    data_str = '{}###################\nPackage {}\n' \
                               '###################\n\n' \
                               '{}\n'.format(data_str, package._get_pname(),
                                             pk_str)
        for model in self._models.values():
            if formal:
                mod_repr = repr(model)
                if len(mod_repr.strip()) > 0:
                    data_str = '{}@@@@@@@@@@@@@@@@@@@@\nModel {}\n' \
                               '@@@@@@@@@@@@@@@@@@@@\n\n' \
                               '{}\n'.format(data_str, model.name, mod_repr)
            else:
                mod_str = str(model)
                if len(mod_str.strip()) > 0:
                    data_str = '{}@@@@@@@@@@@@@@@@@@@@\nModel {}\n' \
                               '@@@@@@@@@@@@@@@@@@@@\n\n' \
                               '{}\n'.format(data_str, model.name, mod_str)
        return data_str

    @property
    def model_names(self):
        """Return a list of model names associated with this simulation.

        Returns:
            list: list of model names

        """
        return self._models.keys()

    @classmethod
    def load(cls, sim_name='modflowsim', version='mf6', exe_name='mf6.exe',
             sim_ws='.', strict=True, verbosity_level=1, load_only=None,
             verify_data=False):
        """Load an existing model.

        Parameters
        ----------
        sim_name : string
            name of the simulation.
        version : string
            MODFLOW version
        exe_name : string
            relative path to MODFLOW executable from the simulation working
            folder
        sim_ws : string
            path to simulation working folder
        strict : boolean
            strict enforcement of file formatting
        verbosity_level : int
            verbosity level of standard output
                0 : no standard output
                1 : standard error/warning messages with some informational
                    messages
                2 : verbose mode with full error/warning/informational
                    messages.  this is ideal for debugging
        load_only : list
            list of package abbreviations or package names corresponding to
            packages that flopy will load. default is None, which loads all
            packages. the discretization packages will load regardless of this
            setting. subpackages, like time series and observations, will also
            load regardless of this setting.
            example list: ['ic', 'maw', 'npf', 'oc', 'ims', 'gwf6-gwf6']
        verify_data : bool
            verify data when it is loaded. this can slow down loading

        Returns
        -------
        sim : MFSimulation object

        Examples
        --------
        >>> s = flopy.mf6.mfsimulation.load('my simulation')

        """
        # initialize
        instance = cls(sim_name, version, exe_name, sim_ws, verbosity_level)
        verbosity_level = instance.simulation_data.verbosity_level
        instance.simulation_data.verify_data = verify_data

        if verbosity_level.value >= VerbosityLevel.normal.value:
            print('loading simulation...')

        # build case consistent load_only dictionary for quick lookups
        load_only = instance._load_only_dict(load_only)

        # load simulation name file
        if verbosity_level.value >= VerbosityLevel.normal.value:
            print('  loading simulation name file...')
        instance.name_file.load(strict)

        # load TDIS file
        tdis_pkg = 'tdis{}'.format(mfstructure.MFStructure().
                                   get_version_string())
        tdis_attr = getattr(instance.name_file, tdis_pkg)
        instance._tdis_file = mftdis.ModflowTdis(instance,
                                                 filename=tdis_attr.get_data())

        instance._tdis_file._filename = instance.simulation_data.mfdata[
            ('nam', 'timing', tdis_pkg)].get_data()
        if verbosity_level.value >= VerbosityLevel.normal.value:
            print('  loading tdis package...')
        instance._tdis_file.load(strict)

        # load models
        try:
            model_recarray = instance.simulation_data.mfdata[('nam', 'models',
                                                              'models')]
            models = model_recarray.get_data()
        except MFDataException as mfde:
            message = 'Error occurred while loading model names from the ' \
                      'simulation name file.'
            raise MFDataException(mfdata_except=mfde,
                                  model=instance.name,
                                  package='nam',
                                  message=message)
        for item in models:
            # resolve model working folder and name file
            path, name_file = os.path.split(item[1])
            model_obj = PackageContainer.model_factory(item[0][:-1].lower())
            # load model
            if verbosity_level.value >= VerbosityLevel.normal.value:
                print('  loading model {}...'.format(item[0].lower()))
            instance._models[item[2]] = model_obj.load(
                instance,
                instance.structure.model_struct_objs[item[0].lower()], item[2],
                name_file, version, exe_name, strict, path, load_only)

        # load exchange packages and dependent packages
        try:
            exchange_recarray = instance.name_file.exchanges
            has_exch_data = exchange_recarray.has_data()
        except MFDataException as mfde:
            message = 'Error occurred while loading exchange names from the ' \
                      'simulation name file.'
            raise MFDataException(mfdata_except=mfde,
                                  model=instance.name,
                                  package='nam',
                                  message=message)
        if has_exch_data:
            try:
                exch_data = exchange_recarray.get_data()
            except MFDataException as mfde:
                message = 'Error occurred while loading exchange names from ' \
                          'the simulation name file.'
                raise MFDataException(mfdata_except=mfde,
                                      model=instance.name,
                                      package='nam',
                                      message=message)
            for exgfile in exch_data:
                if load_only is not None and not \
                        instance._in_pkg_list(load_only, exgfile[0],
                                              exgfile[2]):
                    if instance.simulation_data.verbosity_level.value >= \
                            VerbosityLevel.normal.value:
                        print('    skipping package {}..'
                              '.'.format(exgfile[0].lower()))
                    continue
                # get exchange type by removing numbers from exgtype
                exchange_type = ''.join([char for char in exgfile[0] if
                                         not char.isdigit()]).upper()
                # get exchange number for this type
                if exchange_type not in instance._exg_file_num:
                    exchange_file_num = 0
                    instance._exg_file_num[exchange_type] = 1
                else:
                    exchange_file_num = instance._exg_file_num[exchange_type]
                    instance._exg_file_num[exchange_type] += 1

                exchange_name = '{}_EXG_{}'.format(exchange_type,
                                                   exchange_file_num)
                # find package class the corresponds to this exchange type
                package_obj = instance.package_factory(
                    exchange_type.replace('-', '').lower(), '')
                if not package_obj:
                    message = 'An error occurred while loading the ' \
                              'simulation name file.  Invalid exchange type ' \
                              '"{}" specified.'.format(exchange_type)
                    type_, value_, traceback_ = sys.exc_info()
                    raise MFDataException(instance.name,
                                          'nam',
                                          'nam',
                                          'loading simulation name file',
                                          exchange_recarray.structure.name,
                                          inspect.stack()[0][3],
                                          type_, value_, traceback_, message,
                                          instance._simulation_data.debug)

                # build and load exchange package object
                exchange_file = package_obj(instance, exgtype=exgfile[0],
                                            exgmnamea=exgfile[2],
                                            exgmnameb=exgfile[3],
                                            filename=exgfile[1],
                                            pname=exchange_name,
                                            loading_package=True)
                if verbosity_level.value >= VerbosityLevel.normal.value:
                    print('  loading exchange package {}..'
                          '.'.format(exchange_file._get_pname()))
                exchange_file.load(strict)
                instance._exchange_files[exgfile[1]] = exchange_file

        # load simulation packages
        solution_recarray = instance.simulation_data.mfdata[('nam',
                                                             'solutiongroup',
                                                             'solutiongroup'
                                                             )]

        try:
            solution_group_dict = solution_recarray.get_data()
        except MFDataException as mfde:
            message = 'Error occurred while loading solution groups from ' \
                      'the simulation name file.'
            raise MFDataException(mfdata_except=mfde,
                                  model=instance.name,
                                  package='nam',
                                  message=message)
        for solution_group in solution_group_dict.values():
            for solution_info in solution_group:
                if load_only is not None and \
                        not instance._in_pkg_list(load_only,
                                                  solution_info[0],
                                                  solution_info[2]):
                    if instance.simulation_data.verbosity_level.value >= \
                            VerbosityLevel.normal.value:
                        print('    skipping package {}..'
                              '.'.format(solution_info[0].lower()))
                    continue
                ims_file = mfims.ModflowIms(instance, filename=solution_info[1],
                                            pname=solution_info[2])
                if verbosity_level.value >= VerbosityLevel.normal.value:
                    print('  loading ims package {}..'
                          '.'.format(ims_file._get_pname()))
                ims_file.load(strict)

        instance.simulation_data.mfpath.set_last_accessed_path()
        if verify_data:
            instance.check()
        return instance

    def check(self, f=None, verbose=True, level=1):
        """
        Check model data for common errors.

        Parameters
        ----------
        f : str or file handle
            String defining file name or file handle for summary file
            of check method output. If a string is passed a file handle
            is created. If f is None, check method does not write
            results to a summary file. (default is None)
        verbose : bool
            Boolean flag used to determine if check method results are
            written to the screen
        level : int
            Check method analysis level. If level=0, summary checks are
            performed. If level=1, full checks are performed.

        Returns
        -------
        None

        Examples
        --------

        >>> import flopy
        >>> m = flopy.modflow.Modflow.load('model.nam')
        >>> m.check()
        """
        # check instance for simulation-level check
        chk_list = []

        # check models
        for model in self._models.values():
            print('Checking model "{}"...'.format(model.name))
            chk_list.append(model.check(f, verbose, level))

        print('Checking for missing simulation packages...')
        if self._tdis_file is None:
            if chk_list:
                chk_list[0]._add_to_summary(
                    'Error', desc='\r    No tdis package', package='model')
            print('Error: no tdis package')
        if len(self._ims_files) == 0:
            if chk_list:
                chk_list[0]._add_to_summary(
                    'Error', desc='\r    No solver package', package='model')
            print('Error: no ims package')
        return chk_list

    @property
    def sim_package_list(self):
        package_list = []
        if self._tdis_file is not None:
            package_list.append(self._tdis_file)
        for sim_package in self._ims_files.values():
            package_list.append(sim_package)
        for sim_package in self._exchange_files.values():
            package_list.append(sim_package)
        for sim_package in self._mover_files.values():
            package_list.append(sim_package)
        for sim_package in self._other_files.values():
            package_list.append(sim_package)
        return package_list

    def load_package(self, ftype, fname, pname, strict, ref_path,
                     dict_package_name=None, parent_package=None):
        """Load a package from a file.

        Parameters
        ----------
        ftype : string
            the file type
        fname : string
            the name of the file containing the package input
        pname : string
            the user-defined name for the package
        strict : bool
            strict mode when loading the file
        ref_path : string
            path to the file. uses local path if set to None
        dict_package_name : string
            package name for dictionary lookup
        parent_package : MFPackage
            parent package

        """
        if ftype == 'gnc':
            if fname not in self._ghost_node_files:
                # get package type from parent package
                if parent_package:
                    package_abbr = parent_package.package_abbr[0:3]
                else:
                    package_abbr = 'GWF'
                # build package name and package
                gnc_name = '{}-GNC_{}'.format(package_abbr, self._gnc_file_num)
                ghost_node_file = mfgwfgnc.ModflowGwfgnc(
                    self, filename=fname, pname=gnc_name,
                    parent_file=parent_package, loading_package=True)
                ghost_node_file.load(strict)
                self._ghost_node_files[fname] = ghost_node_file
                self._gnc_file_num += 1
                return ghost_node_file
        elif ftype == 'mvr':
            if fname not in self._mover_files:
                # Get package type from parent package
                if parent_package:
                    package_abbr = parent_package.package_abbr[0:3]
                else:
                    package_abbr = 'GWF'
                # build package name and package
                mvr_name = '{}-MVR_{}'.format(package_abbr, self._mvr_file_num)
                mover_file = mfgwfmvr.ModflowGwfmvr(self, filename=fname,
                                                    pname=mvr_name,
                                                    parent_file=parent_package,
                                                    loading_package=True)
                mover_file.load(strict)
                self._mover_files[fname] = mover_file
                self._mvr_file_num += 1
                return mover_file
        else:
            # create package
            package_obj = self.package_factory(ftype, '')
            package = package_obj(self, filename=fname, pname=dict_package_name,
                                  add_to_package_list=False,
                                  parent_file=parent_package,
                                  loading_package=True)
            # verify that this is a utility package
            utl_struct = mfstructure.MFStructure().sim_struct.utl_struct_objs
            if package.package_type in utl_struct:
                package.load(strict)
                self._other_files[package.filename] = package
                # register child package with the simulation
                self._add_package(package, package.path)
                if parent_package is not None:
                    # register child package with the parent package
                    parent_package._add_package(package, package.path)
            else:
                if self.simulation_data.verbosity_level.value >= \
                        VerbosityLevel.normal.value:
                    print('WARNING: Unsupported file type {} for '
                          'simulation.'.format(package.package_type))
            return package

    def register_ims_package(self, ims_file, model_list):
        """Register an ims package with the simulation.

        Parameters
            ims_file : MFPackage
                ims package to register
            model_list : list of strings
                list of models using the ims package to be registered

        """
        if isinstance(model_list, str):
            model_list = [model_list]

        if not isinstance(ims_file, mfims.ModflowIms):
            comment = 'Parameter "ims_file" is not a valid ims file.  ' \
                      'Expected type ModflowIms, but type "{}" was given' \
                      '.'.format(type(ims_file))
            type_, value_, traceback_ = sys.exc_info()
            raise MFDataException(None,
                                  'ims',
                                  '',
                                  'registering ims package',
                                  '',
                                  inspect.stack()[0][3], type_,
                                  value_,
                                  traceback_, comment,
                                  self.simulation_data.debug)

        in_simulation = False
        pkg_with_same_name = None
        for file in self._ims_files.values():
            if file is ims_file:
                in_simulation = True
            if file.package_name == ims_file.package_name and \
                    file != ims_file:
                pkg_with_same_name = file
                if self.simulation_data.verbosity_level.value >= \
                        VerbosityLevel.normal.value:
                    print('WARNING: ims package with name {} already exists. '
                          'New ims package will replace old package'
                          '.'.format(file.package_name))
                self._remove_package(self._ims_files[file.filename])
                del self._ims_files[file.filename]
        # register ims package
        if not in_simulation:
            self._add_package(ims_file, self._get_package_path(ims_file))
        # do not allow an ims package to be registered twice with the
        # same simulation
        if not in_simulation:
            # create unique file/package name
            if ims_file.package_name is None:
                file_num = len(self._ims_files) - 1
                ims_file.package_name = 'ims_{}'.format(file_num)
            if ims_file.filename in self._ims_files:
                ims_file.filename = MFFileMgmt.unique_file_name(
                    ims_file.filename, self._ims_files)
            # add ims package to simulation
            self._ims_files[ims_file.filename] = ims_file

        # If ims file is being replaced, replace ims filename in solution group
        if pkg_with_same_name is not None and \
                self._is_in_solution_group(pkg_with_same_name.filename, 1):
            # change existing solution group to reflect new ims file
            self._replace_ims_in_solution_group(pkg_with_same_name.filename,
                                                1, ims_file.filename)
        # only allow an ims package to be registered to one solution group
        elif model_list is not None:
            ims_in_group = self._is_in_solution_group(ims_file.filename, 1)
            # add solution group to the simulation name file
            solution_recarray = self.name_file.solutiongroup
            solution_group_list = solution_recarray.get_active_key_list()
            if len(solution_group_list) == 0:
                solution_group_num = 0
            else:
                solution_group_num = solution_group_list[-1][0]

            if ims_in_group:
                self._append_to_ims_solution_group(ims_file.filename,
                                                   model_list)
            else:
                if self.name_file.mxiter.get_data(solution_group_num) is None:
                    self.name_file.mxiter.add_transient_key(solution_group_num)

                # associate any models in the model list to this
                # simulation file
                version_string = mfstructure.MFStructure().get_version_string()
                ims_pkg = 'ims{}'.format(version_string)
                new_record = [ims_pkg, ims_file.filename]
                for model in model_list:
                    new_record.append(model)
                try:
                    solution_recarray.append_list_as_record(new_record,
                                                            solution_group_num)
                except MFDataException as mfde:
                    message = 'Error occurred while updating the ' \
                              'simulation name file with the ims package ' \
                              'file "{}".'.format(ims_file.filename)
                    raise MFDataException(mfdata_except=mfde,
                                          package='nam',
                                          message=message)

    @staticmethod
    def _rename_package_group(group_dict, name):
        package_type_count = {}
        for package in group_dict.values():
            if package.package_type not in package_type_count:
                package.filename = '{}.{}'.format(name, package.package_type)
                package_type_count[package.package_type] = 1
            else:
                package_type_count[package.package_type] += 1
                package.filename = '{}_{}.{}'.format(
                    name, package_type_count[package.package.package_type],
                    package.package_type)

    def rename_all_packages(self, name):
        """Rename all packages with name as prefix.

        Parameters:
            name (str): prefix of name

        """
        if self._tdis_file is not None:
            self._tdis_file.filename = '{}.{}'.format(
                name, self._tdis_file.package_type)

        self._rename_package_group(self._exchange_files, name)
        self._rename_package_group(self._ims_files, name)
        self._rename_package_group(self._ghost_node_files, name)
        self._rename_package_group(self._mover_files, name)
        self._rename_package_group(self._other_files, name)
        for model in self._models.values():
            model.rename_all_packages(name)

    def set_all_data_external(self):
        # copy any files whose paths have changed
        self.simulation_data.mfpath.copy_files()
        # set data external for all packages in all models
        for model in self._models.values():
            model.set_all_data_external()
        # set data external for ims packages
        for package in self._ims_files.values():
            package.set_all_data_external()
        # set data external for ghost node packages
        for package in self._ghost_node_files.values():
            package.set_all_data_external()
        # set data external for mover packages
        for package in self._mover_files.values():
            package.set_all_data_external()

    def write_simulation(self,
                         ext_file_action=ExtFileAction.copy_relative_paths,
                         silent=False):
        """Write the simulation to files.

        Parameters
            ext_file_action : ExtFileAction
                defines what to do with external files when the simulation path
                has changed.  defaults to copy_relative_paths which copies only
                files with relative paths, leaving files defined by absolute
                paths fixed.
            silent : bool
                writes out the simulation in silent mode (verbosity_level = 0)

        """
        saved_verb_lvl = self.simulation_data.verbosity_level
        if silent:
            self.simulation_data.verbosity_level = VerbosityLevel.quiet

        # write simulation name file
        if self.simulation_data.verbosity_level.value >= \
                VerbosityLevel.normal.value:
            print('writing simulation...')
            print('  writing simulation name file...')
        self.name_file.write(ext_file_action=ext_file_action)

        # write TDIS file
        if self.simulation_data.verbosity_level.value >= \
                VerbosityLevel.normal.value:
            print('  writing simulation tdis package...')
        self._tdis_file.write(ext_file_action=ext_file_action)

        # write ims files
        for ims_file in self._ims_files.values():
            if self.simulation_data.verbosity_level.value >= \
                    VerbosityLevel.normal.value:
                print('  writing ims package {}...'.format(
                    ims_file._get_pname()))
            ims_file.write(ext_file_action=ext_file_action)

        # write exchange files
        for exchange_file in self._exchange_files.values():
            exchange_file.write()
            if hasattr(exchange_file, 'gnc_filerecord') and \
                    exchange_file.gnc_filerecord.has_data():
                try:
                    gnc_file = exchange_file.gnc_filerecord.get_data()[0][0]
                except MFDataException as mfde:
                    message = 'An error occurred while retrieving the ghost ' \
                              'node file record from exchange file ' \
                              '"{}".'.format(exchange_file.filename)
                    raise MFDataException(mfdata_except=mfde,
                                          package=exchange_file._get_pname(),
                                          message=message)
                if gnc_file in self._ghost_node_files:
                    if self.simulation_data.verbosity_level.value >= \
                            VerbosityLevel.normal.value:
                        print('  writing gnc package {}...'.format(
                            self._ghost_node_files[gnc_file]._get_pname()))
                    self._ghost_node_files[gnc_file].write(
                        ext_file_action=ext_file_action)
                else:
                    if self.simulation_data.verbosity_level.value >= \
                            VerbosityLevel.normal.value:
                        print('WARNING: Ghost node file {} not loaded prior to'
                              ' writing. File will not be written'
                              '.'.format(gnc_file))
            if hasattr(exchange_file, 'mvr_filerecord') and \
                    exchange_file.mvr_filerecord.has_data():
                try:
                    mvr_file = exchange_file.mvr_filerecord.get_data()[0][0]
                except MFDataException as mfde:
                    message = 'An error occurred while retrieving the mover ' \
                              'file record from exchange file ' \
                              '"{}".'.format(exchange_file.filename)
                    raise MFDataException(mfdata_except=mfde,
                                          package=exchange_file._get_pname(),
                                          message=message)

                if mvr_file in self._mover_files:
                    if self.simulation_data.verbosity_level.value >= \
                            VerbosityLevel.normal.value:
                        print('  writing mvr package {}...'.format(
                            self._mover_files[mvr_file]._get_pname()))
                    self._mover_files[mvr_file].write(
                        ext_file_action=ext_file_action)
                else:
                    if self.simulation_data.verbosity_level.value >= \
                            VerbosityLevel.normal.value:
                        print('WARNING: Mover file {} not loaded prior to '
                              'writing. File will not be '
                              'written.'.format(mvr_file))

        if ext_file_action == ExtFileAction.copy_relative_paths:
            # move external files with relative paths
            num_files_copied = self.simulation_data.mfpath.copy_files()
        elif ext_file_action == ExtFileAction.copy_all:
            # move all external files
            num_files_copied = self.simulation_data.mfpath.copy_files(
                copy_relative_only=False)
        else:
            num_files_copied = 0
        if self.simulation_data.verbosity_level.value >= \
                VerbosityLevel.verbose.value and num_files_copied > 0:
            print('INFORMATION: {} external files copied'.format(
                num_files_copied))

        # write other packages
        for pp in self._other_files.values():
            if self.simulation_data.verbosity_level.value >= \
                    VerbosityLevel.normal.value:
                print('  writing package {}...'.format(pp._get_pname()))
            pp.write(ext_file_action=ext_file_action)

        # FIX: model working folder should be model name file folder

        # write models
        for model in self._models.values():
            if self.simulation_data.verbosity_level.value >= \
                    VerbosityLevel.normal.value:
                print('  writing model {}...'.format(model.name))
            model.write(ext_file_action=ext_file_action)

        self.simulation_data.mfpath.set_last_accessed_path()

        if silent:
            self.simulation_data.verbosity_level = saved_verb_lvl

    def set_sim_path(self, path):
        """Return a list of output data keys.

        Parameters:
            print_keys (bool): print keys to console

        Returns:
            list: keys for requesting binary output

        """
        self.simulation_data.mfpath.set_sim_path(path)

    def run_simulation(self, silent=None, pause=False, report=False,
                       normal_msg='normal termination',
                       use_async=False, cargs=None):
        """Run the simulation.

        Parameters:
            silent (bool):
                run in silent mode
            pause (bool):
                pause at end of run
            report (bool):
                save stdout lines to a list (buff)
            normal_msg (str or list):
                Normal termination message used to determine if the run
                terminated normally. More than one message can be provided
                using a list. (default is 'normal termination')
            use_async : (boolean)
                asynchronously read model stdout and report with timestamps.
                good for models that take long time to run.  not good for
                models that run really fast
            cargs : (str or list of strings)
                additional command line arguments to pass to the executable.
                default is None
        Returns:
            (success, buff)
                success : boolean
                buff : list of lines of stdout

        """
        if silent is None:
            if self.simulation_data.verbosity_level.value >= \
                    VerbosityLevel.normal.value:
                silent = False
            else:
                silent = True
        return run_model(self.exe_name, None,
                         self.simulation_data.mfpath.get_sim_path(),
                         silent=silent, pause=pause, report=report,
                         normal_msg=normal_msg, use_async=use_async, cargs=cargs)

    def delete_output_files(self):
        """Delete simulation output files."""
        output_req = binaryfile_utils.MFOutputRequester
        output_file_keys = output_req.getkeys(self.simulation_data.mfdata,
                                              self.simulation_data.mfpath,
                                              False)
        for path in output_file_keys.binarypathdict.values():
            if os.path.isfile(path):
                os.remove(path)

    def remove_package(self, package_name):
        """Remove a package.

        Parameters:
            package_name (str): name of package to be removed

        """
        if isinstance(package_name, MFPackage):
            packages = [package_name]
        else:
            packages = self.get_package(package_name)
            if not isinstance(packages, list):
                packages = [packages]
        for package in packages:
            if self._tdis_file is not None and \
                    package.path == self._tdis_file.path:
                self._tdis_file = None
            if package.filename in self._exchange_files:
                del self._exchange_files[package.filename]
            if package.filename in self._ims_files:
                del self._ims_files[package.filename]
                self._remove_ims_soultion_group(package.filename)
            if package.filename in self._ghost_node_files:
                del self._ghost_node_files[package.filename]
            if package.filename in self._mover_files:
                del self._mover_files[package.filename]
            if package.filename in self._other_files:
                del self._other_files[package.filename]

            self._remove_package(package)

    @property
    def model_dict(self):
        """Return a dictionary of models.

        Returns:
            model dict : dict
                dictionary of models

        """
        return self._models.copy()

    def get_model(self, model_name=None):
        """Load an existing model.

        Parameters:
            model_name : string
                name of model to get

        Returns:
            model : MFModel

        """
        if len(self._models) == 0:
            return None

        if model_name is None:
            for model in self._models.values():
                return model
        if model_name in self._models:
            return self._models[model_name]
        # do case-insensitive lookup
        for name, model in self._models.items():
            if model_name.lower() == name.lower():
                return model
        return None

    def get_exchange_file(self, filename):
        """Get a specified exchange file.

        Parameters:
            filename : string
                name of exchange file to get

        Returns:
            exchange package : MFPackage

        """
        if filename in self._exchange_files:
            return self._exchange_files[filename]
        else:
            excpt_str = 'Exchange file "{}" can not be found' \
                        '.'.format(filename)
            raise FlopyException(excpt_str)

    def get_mvr_file(self, filename):
        """Get a specified mover file.

        Parameters:
            filename : string
                name of mover file to get

        Returns:
            mover package : MFPackage

        """
        if filename in self._mover_files:
            return self._mover_files[filename]
        else:
            excpt_str = 'MVR file "{}" can not be ' \
                        'found.'.format(filename)
            raise FlopyException(excpt_str)

    def get_gnc_file(self, filename):
        """Get a specified gnc file.

        Parameters:
            filename : string
                name of gnc file to get

        Returns:
            gnc package : MFPackage

        """
        if filename in self._ghost_node_files:
            return self._ghost_node_files[filename]
        else:
            excpt_str = 'GNC file "{}" can not be ' \
                        'found.'.format(filename)
            raise FlopyException(excpt_str)

    def register_exchange_file(self, package):
        """Register an exchange package file with the simulation.

        Parameters:
            package : MFPackage
                exchange package object to register

        """
        if package.filename not in self._exchange_files:
            exgtype = package.exgtype
            exgmnamea = package.exgmnamea
            exgmnameb = package.exgmnameb

            if exgtype is None or exgmnamea is None or exgmnameb is None:
                excpt_str = 'Exchange packages require that exgtype, ' \
                            'exgmnamea, and exgmnameb are specified.'
                raise FlopyException(excpt_str)

            self._exchange_files[package.filename] = package
            try:
                exchange_recarray_data = self.name_file.exchanges.get_data()
            except MFDataException as mfde:
                message = 'An error occurred while retrieving exchange ' \
                          'data from the simulation name file.  The error ' \
                          'occurred while registering exchange file ' \
                          '"{}".'.format(package.filename)
                raise MFDataException(mfdata_except=mfde,
                                      package=package._get_pname(),
                                      message=message)
            if exchange_recarray_data is not None:
                for index, exchange in zip(range(0,
                                                 len(exchange_recarray_data)),
                                           exchange_recarray_data):
                    if exchange[1] == package.filename:
                        # update existing exchange
                        exchange_recarray_data[index][0] = exgtype
                        exchange_recarray_data[index][2] = exgmnamea
                        exchange_recarray_data[index][3] = exgmnameb
                        ex_recarray = self.name_file.exchanges
                        try:
                            ex_recarray.set_data(exchange_recarray_data)
                        except MFDataException as mfde:
                            message = 'An error occurred while setting ' \
                                      'exchange data in the simulation name ' \
                                      'file.  The error occurred while ' \
                                      'registering the following ' \
                                      'values (exgtype, filename, ' \
                                      'exgmnamea, exgmnameb): "{} {} {}' \
                                      '{}".'.format(exgtype, package.filename,
                                                    exgmnamea, exgmnameb)
                            raise MFDataException(mfdata_except=mfde,
                                                  package=package._get_pname(),
                                                  message=message)
                        return
            try:
                # add new exchange
                self.name_file.exchanges.append_data([(exgtype,
                                                       package.filename,
                                                       exgmnamea,
                                                       exgmnameb)])
            except MFDataException as mfde:
                message = 'An error occurred while setting exchange data ' \
                          'in the simulation name file.  The error occurred ' \
                          'while registering the following values (exgtype, ' \
                          'filename, exgmnamea, exgmnameb): "{} {} {}' \
                          '{}".'.format(exgtype, package.filename, exgmnamea,
                                        exgmnameb)
                raise MFDataException(mfdata_except=mfde,
                                      package=package._get_pname(),
                                      message=message)
            if package.dimensions is None:
                # resolve exchange package dimensions object
                package.dimensions = package.create_package_dimensions()

    def register_package(self, package, add_to_package_list=True,
                         set_package_name=True, set_package_filename=True):
        """Register a package file with the simulation.

        Parameters:
            package : MFPackage
                package to register
            add_to_package_list : bool
                add package to lookup list
            set_package_name : bool
                produce a package name for this package
            set_package_filename : bool
                produce a filename for this package

        Returns:
            (path : tuple, package structure : MFPackageStructure)

        """
        package.container_type = [PackageContainerType.simulation]
        path = self._get_package_path(package)
        if add_to_package_list and package.package_type.lower != 'nam':
            pname = None
            if package.package_name is not None:
                pname = package.package_name.lower()
            if package.package_type.lower() == 'tdis' and self._tdis_file is \
                    not None and self._tdis_file in self._packagelist:
                # tdis package already exists. there can be only one tdis
                # package.  remove existing tdis package
                if self.simulation_data.verbosity_level.value >= \
                        VerbosityLevel.normal.value:
                    print('WARNING: tdis package already exists. Replacing '
                          'existing tdis package.')
                self._remove_package(self._tdis_file)
            elif package.package_type.lower() == 'gnc' and \
                    package.filename in self._ghost_node_files and \
                    self._ghost_node_files[package.filename] in self._packagelist:
                # gnc package with same file name already exists.  remove old
                # gnc package
                if self.simulation_data.verbosity_level.value >= \
                        VerbosityLevel.normal.value:
                    print('WARNING: gnc package with name {} already exists. '
                          'Replacing existing gnc package'
                          '.'.format(pname))
                self._remove_package(self._ghost_node_files[package.filename])
                del self._ghost_node_files[package.filename]
            elif package.package_type.lower() == 'mvr' and \
                     package.filename in self._mover_files and \
                     self._mover_files[package.filename] in self._packagelist:
                # mvr package with same file name already exists.  remove old
                # mvr package
                if self.simulation_data.verbosity_level.value >= \
                        VerbosityLevel.normal.value:
                    print('WARNING: mvr package with name {} already exists. '
                          'Replacing existing mvr package'
                          '.'.format(pname))
                self._remove_package(self._mover_files[package.filename])
                del self._mover_files[package.filename]
            elif package.package_type.lower() != 'ims' and pname in \
                    self.package_name_dict:
                if self.simulation_data.verbosity_level.value >= \
                        VerbosityLevel.normal.value:
                    print('WARNING: Package with name {} already exists.  '
                          'Replacing existing package'
                          '.'.format(package.package_name.lower()))
                self._remove_package(self.package_name_dict[pname])
            if package.package_type.lower() != 'ims':
                # all but ims packages get added here.  ims packages are
                # added during ims package registration
                self._add_package(package, path)
        if package.package_type.lower() == 'nam':
            return path, self.structure.name_file_struct_obj
        elif package.package_type.lower() == 'tdis':
            self._tdis_file = package
            struct_root = mfstructure.MFStructure()
            tdis_pkg = 'tdis{}'.format(struct_root.get_version_string())
            tdis_attr = getattr(self.name_file, tdis_pkg)
            try:
                tdis_attr.set_data(package.filename)
            except MFDataException as mfde:
                message = 'An error occurred while setting the tdis package ' \
                          'file name "{}".  The error occurred while ' \
                          'registering the tdis package with the ' \
                          'simulation'.format(package.filename)
                raise MFDataException(mfdata_except=mfde,
                                      package=package._get_pname(),
                                      message=message)
            return path, self.structure.package_struct_objs[
                package.package_type.lower()]
        elif package.package_type.lower() == 'gnc':
            if package.filename not in self._ghost_node_files:
                self._ghost_node_files[package.filename] = package
                self._gnc_file_num += 1
            elif self._ghost_node_files[package.filename] != package:
                # auto generate a unique file name and register it
                file_name = MFFileMgmt.unique_file_name(package.filename,
                                                        self._ghost_node_files)
                package.filename = file_name
                self._ghost_node_files[file_name] = package
        elif package.package_type.lower() == 'mvr':
            if package.filename not in self._mover_files:
                self._mover_files[package.filename] = package
            else:
                # auto generate a unique file name and register it
                file_name = MFFileMgmt.unique_file_name(package.filename,
                                                        self._mover_files)
                package.filename = file_name
                self._mover_files[file_name] = package
        elif package.package_type.lower() == 'ims':
            # default behavior is to register the ims package with the first
            # unregistered model
            unregistered_models = []
            for model in self._models:
                model_registered = self._is_in_solution_group(model, 2)
                if not model_registered:
                    unregistered_models.append(model)
            if unregistered_models:
                self.register_ims_package(package, unregistered_models)
            else:
                self.register_ims_package(package, None)
            return path, self.structure.package_struct_objs[
                package.package_type.lower()]
        else:
            self._other_files[package.filename] = package

        if package.package_type.lower() in self.structure.package_struct_objs:
            return path, self.structure.package_struct_objs[
                package.package_type.lower()]
        elif package.package_type.lower() in self.structure.utl_struct_objs:
            return path, self.structure.utl_struct_objs[
                package.package_type.lower()]
        else:
            excpt_str = 'Invalid package type "{}".  Unable to register ' \
                        'package.'.format(package.package_type)
            print(excpt_str)
            raise FlopyException(excpt_str)

    def register_model(self, model, model_type, model_name, model_namefile):
        """Add a model to the simulation.

        Parameters:
            model : MFModel
                model object to add to simulation
            sln_group : string
                solution group of model

        Returns:
            model_structure_object : MFModelStructure

        """
        # get model structure from model type
        if model_type not in self.structure.model_struct_objs:
            message = 'Invalid model type: "{}".'.format(model_type)
            type_, value_, traceback_ = sys.exc_info()
            raise MFDataException(model.name,
                                  '', model.name,
                                  'registering model', 'sim',
                                  inspect.stack()[0][3],
                                  type_, value_, traceback_, message,
                                  self.simulation_data.debug)

        # add model
        self._models[model_name] = model

        # update simulation name file
        self.name_file.models.append_list_as_record([model_type,
                                                            model_namefile,
                                                            model_name])

        if len(self._ims_files) > 0:
            # register model with first ims file found
            first_ims_key = next(iter(self._ims_files))
            self.register_ims_package(self._ims_files[first_ims_key],
                                      model_name)

        return self.structure.model_struct_objs[model_type]

    def get_ims_package(self, key):
        """Add a model to the simulation.

        Parameters:
            key : str
                ims package key

        Returns:
            ims_package : ModflowIms

        """
        if key in self._ims_files:
            return self._ims_files[key]
        return None

    def remove_model(self, model_name):
        """Remove a model from the simulation.

        Parameters:
            model_name : string
                model name to remove from simulation

        """
        # Remove model
        del self._models[model_name]

        # TODO: Fully implement this
        # Update simulation name file

    def is_valid(self):
        """Check all packages and models in the simulation to verify validity.

        Returns:
            valid : boolean
                simulation validity

        """
        # name file valid
        if not self.name_file.is_valid():
            return False

        # tdis file valid
        if not self._tdis_file.is_valid():
            return False

        # exchanges valid
        for exchange in self._exchange_files:
            if not exchange.is_valid():
                return False

        # ims files valid
        for imsfile in self._ims_files.values():
            if not imsfile.is_valid():
                return False

        # a model exists
        if not self._models:
            return False

        # models valid
        for key in self._models:
            if not self._models[key].is_valid():
                return False

        # each model has an imsfile

        return True

    @staticmethod
    def _resolve_verbosity_level(verbosity_level):
        if verbosity_level == 0:
            return VerbosityLevel.quiet
        elif verbosity_level == 1:
            return VerbosityLevel.normal
        elif verbosity_level == 2:
            return VerbosityLevel.verbose
        else:
            return verbosity_level

    @staticmethod
    def _get_package_path(package):
        if package.parent_file is not None:
            return (package.parent_file.path) + (package.package_type,)
        else:
            return (package.package_type,)

    def _remove_ims_soultion_group(self, ims_file):
        solution_recarray = self.name_file.solutiongroup
        for solution_group_num in solution_recarray.get_active_key_list():
            try:
                rec_array = solution_recarray.get_data(solution_group_num[0])
            except MFDataException as mfde:
                message = 'An error occurred while getting solution group' \
                          '"{}" from the simulation name file' \
                          '.'.format(solution_group_num[0])
                raise MFDataException(mfdata_except=mfde,
                                      package='nam',
                                      message=message)

            new_array = []
            for record in rec_array:
                if record.slnfname == ims_file:
                    continue
                else:
                    new_array.append(record)

            if not new_array:
                new_array = None

            solution_recarray.set_data(new_array, solution_group_num[0])

    def _append_to_ims_solution_group(self, ims_file, new_models):
        solution_recarray = self.name_file.solutiongroup
        for solution_group_num in solution_recarray.get_active_key_list():
            try:
                rec_array = solution_recarray.get_data(solution_group_num[0])
            except MFDataException as mfde:
                message = 'An error occurred while getting solution group' \
                          '"{}" from the simulation name file' \
                          '.'.format(solution_group_num[0])
                raise MFDataException(mfdata_except=mfde,
                                      package='nam',
                                      message=message)
            new_array = []
            for index, record in enumerate(rec_array):
                new_record = []
                rec_model_dict = {}
                for index, item in enumerate(record):
                    if record[1] == ims_file or item not in new_models:
                        new_record.append(item)
                        if index > 1 and item is not None:
                            rec_model_dict[item.lower()] = 1

                if record[1] == ims_file:
                    for model in new_models:
                        if model.lower() not in rec_model_dict:
                            new_record.append(model)

                new_array.append(tuple(new_record))
            solution_recarray.set_data(new_array,
                                       solution_group_num[0])

    def _replace_ims_in_solution_group(self, item, index, new_item):
        solution_recarray = self.name_file.solutiongroup
        for solution_group_num in solution_recarray.get_active_key_list():
            try:
                rec_array = solution_recarray.get_data(solution_group_num[0])
            except MFDataException as mfde:
                message = 'An error occurred while getting solution group' \
                          '"{}" from the simulation name file.  The error ' \
                          'occurred while replacing IMS file "{}" with "{}"' \
                          'at index "{}"'.format(solution_group_num[0],
                                                 item, new_item, index)
                raise MFDataException(mfdata_except=mfde,
                                      package='nam',
                                      message=message)
            if rec_array is not None:
                for rec_item in rec_array:
                    if rec_item[index] == item:
                        rec_item[index] = new_item

    def _is_in_solution_group(self, item, index):
        solution_recarray = self.name_file.solutiongroup
        for solution_group_num in solution_recarray.get_active_key_list():
            try:
                rec_array = solution_recarray.get_data(solution_group_num[0])
            except MFDataException as mfde:
                message = 'An error occurred while getting solution group' \
                          '"{}" from the simulation name file.  The error ' \
                          'occurred while verifying file "{}" at index "{}" ' \
                          'is in the simulation name file' \
                          '.'.format(solution_group_num[0], item, index)
                raise MFDataException(mfdata_except=mfde,
                                      package='nam',
                                      message=message)

            if rec_array is not None:
                for rec_item in rec_array:
                    if rec_item[index] == item:
                        return True
        return False

    def plot(self, model_list=None, SelPackList=None, **kwargs):
        """Plot simulation or models.

        Method to plot a whole simulation or a series of models
        that are part of a simulation.

        Parameters:
            model_list: (list) list of model names to plot, if none
                all models will be plotted
            SelPackList: (list) list of package names to plot, if none
                all packages will be plotted
            kwargs:
                filename_base : str
                    Base file name that will be used to automatically generate file
                    names for output image files. Plots will be exported as image
                    files if file_name_base is not None. (default is None)
                file_extension : str
                    Valid matplotlib.pyplot file extension for savefig(). Only used
                    if filename_base is not None. (default is 'png')
                mflay : int
                    MODFLOW zero-based layer number to return.  If None, then all
                    all layers will be included. (default is None)
                kper : int
                    MODFLOW zero-based stress period number to return.
                    (default is zero)
                key : str
                    MfList dictionary key. (default is None)

        Returns:
             axes: (list) matplotlib.pyplot.axes objects

        """
        from flopy.plot.plotutil import PlotUtilities

        axes = PlotUtilities._plot_simulation_helper(self,
                                                     model_list=model_list,
                                                     SelPackList=SelPackList,
                                                     **kwargs)
        return axes