diff --git a/processing/post/DADF5_postResults.py b/processing/post/DADF5_postResults.py
index 0db018173..a16ef147c 100755
--- a/processing/post/DADF5_postResults.py
+++ b/processing/post/DADF5_postResults.py
@@ -65,7 +65,7 @@ for filename in options.filenames:
           x = results.get_dataset_location(label)
           if len(x) == 0:
             continue
-          array = results.read_dataset(x,0)
+          array = results.read_dataset(x,0,plain=True)
           d = int(np.product(np.shape(array)[1:]))
           data = np.concatenate((data,np.reshape(array,[np.product(results.grid),d])),1)
           
@@ -80,7 +80,7 @@ for filename in options.filenames:
           x = results.get_dataset_location(label)
           if len(x) == 0:
             continue
-          array = results.read_dataset(x,0)
+          array = results.read_dataset(x,0,plain=True)
           d = int(np.product(np.shape(array)[1:]))
           data = np.concatenate((data,np.reshape(array,[np.product(results.grid),d])),1)
           
diff --git a/processing/pre/geom_clean.py b/processing/pre/geom_clean.py
index aeafe4f09..50f3657b2 100755
--- a/processing/pre/geom_clean.py
+++ b/processing/pre/geom_clean.py
@@ -5,9 +5,6 @@ import sys
 from io import StringIO
 from optparse import OptionParser
 
-from scipy import ndimage
-import numpy as np
-
 import damask
 
 
@@ -15,11 +12,6 @@ scriptName = os.path.splitext(os.path.basename(__file__))[0]
 scriptID   = ' '.join([scriptName,damask.version])
 
 
-def mostFrequent(arr):
-  unique, inverse = np.unique(arr, return_inverse=True)
-  return unique[np.argmax(np.bincount(inverse))]
-
-
 #--------------------------------------------------------------------------------------------------
 #                                MAIN
 #--------------------------------------------------------------------------------------------------
@@ -46,9 +38,8 @@ for name in filenames:
 
   geom = damask.Geom.from_file(StringIO(''.join(sys.stdin.read())) if name is None else name)
 
-  damask.util.croak(geom.update(ndimage.filters.generic_filter(
-                                  geom.microstructure,mostFrequent,
-                                  size=(options.stencil,)*3).astype(geom.microstructure.dtype)))
+  damask.util.croak(geom.clean(options.stencil))
+
   geom.add_comments(scriptID + ' ' + ' '.join(sys.argv[1:]))
 
   if name is None:
diff --git a/processing/pre/geom_mirror.py b/processing/pre/geom_mirror.py
index 67bd2366f..77ec1f4d7 100755
--- a/processing/pre/geom_mirror.py
+++ b/processing/pre/geom_mirror.py
@@ -5,8 +5,6 @@ import sys
 from io import StringIO
 from optparse import OptionParser
 
-import numpy as np
-
 import damask
 
 
@@ -38,16 +36,6 @@ parser.set_defaults(reflect = False)
 
 (options, filenames) = parser.parse_args()
 
-if options.directions is None:
-  parser.error('no direction given.')
-
-if not set(options.directions).issubset(validDirections):
-  invalidDirections = [str(e) for e in set(options.directions).difference(validDirections)]
-  parser.error('invalid directions {}. '.format(*invalidDirections))
-
-limits = [None,None] if options.reflect else [-2,0]
-
-
 if filenames == []: filenames = [None]
 
 for name in filenames:
@@ -55,15 +43,7 @@ for name in filenames:
 
   geom = damask.Geom.from_file(StringIO(''.join(sys.stdin.read())) if name is None else name)
 
-  microstructure = geom.get_microstructure()
-  if 'z' in options.directions:
-    microstructure = np.concatenate([microstructure,microstructure[:,:,limits[0]:limits[1]:-1]],2)
-  if 'y' in options.directions:
-    microstructure = np.concatenate([microstructure,microstructure[:,limits[0]:limits[1]:-1,:]],1)
-  if 'x' in options.directions:
-    microstructure = np.concatenate([microstructure,microstructure[limits[0]:limits[1]:-1,:,:]],0)
-
-  damask.util.croak(geom.update(microstructure,rescale=True))
+  damask.util.croak(geom.mirror(options.directions,options.reflect))
   geom.add_comments(scriptID + ' ' + ' '.join(sys.argv[1:]))
 
   if name is None:
diff --git a/python/damask/__init__.py b/python/damask/__init__.py
index f876d1417..f432ef056 100644
--- a/python/damask/__init__.py
+++ b/python/damask/__init__.py
@@ -2,7 +2,7 @@
 import os
 
 with open(os.path.join(os.path.dirname(__file__),'VERSION')) as f:
-  version = f.readline()[1:-1]
+    version = f.readline()[1:-1]
 
 name = 'damask'
 
diff --git a/python/damask/asciitable.py b/python/damask/asciitable.py
index 59e285d6a..13ca0116b 100644
--- a/python/damask/asciitable.py
+++ b/python/damask/asciitable.py
@@ -2,7 +2,7 @@ import os
 import sys
 import re
 import shlex
-from collections import Iterable
+from collections.abc import Iterable
 
 import numpy as np
 
@@ -15,7 +15,7 @@ except NameError:
 
 # ------------------------------------------------------------------
 class ASCIItable():
-  """Read and write to ASCII tables"""
+  """Read and write to ASCII tables."""
 
   tmpext = '_tmp'                                                                                   # filename extension for in-place access
   
@@ -27,6 +27,7 @@ class ASCIItable():
                labeled   = True,                                                                    # assume table has labels
                readonly  = False,                                                                   # no reading from file
               ):
+    """Read and write to ASCII tables."""
     self.__IO__ = {'output': [],
                    'buffered': buffered,
                    'labeled':  labeled,                                                             # header contains labels
@@ -72,7 +73,7 @@ class ASCIItable():
 # ------------------------------------------------------------------
   def _removeCRLF(self,
                   string):
-    """Delete any carriage return and line feed from string"""
+    """Delete any carriage return and line feed from string."""
     try:
       return string.replace('\n','').replace('\r','')
     except AttributeError:
@@ -82,7 +83,7 @@ class ASCIItable():
 # ------------------------------------------------------------------
   def _quote(self,
              what):
-    """Quote empty or white space-containing output"""
+    """Quote empty or white space-containing output."""
     return '{quote}{content}{quote}'.format(
              quote   = ('"' if str(what)=='' or re.search(r"\s",str(what)) else ''),
              content = what)
@@ -103,7 +104,7 @@ class ASCIItable():
 # ------------------------------------------------------------------
   def output_write(self,
                    what):
-    """Aggregate a single row (string) or list of (possibly containing further lists of) rows into output"""
+    """Aggregate a single row (string) or list of (possibly containing further lists of) rows into output."""
     if isinstance(what, (str, unicode)):
       self.__IO__['output'] += [what]
     else:
@@ -143,7 +144,7 @@ class ASCIItable():
 # ------------------------------------------------------------------
   def head_read(self):
     """
-    Get column labels
+    Get column labels.
     
     by either reading the first row or,
     if keyword "head[*]" is present, the last line of the header
@@ -154,7 +155,7 @@ class ASCIItable():
       pass
 
     firstline = self.__IO__['in'].readline().strip()
-    m = re.search('(\d+)\s+head', firstline.lower())                                                # search for "head" keyword
+    m = re.search(r'(\d+)\s+head', firstline.lower())                                                # search for "head" keyword
     
     if m:                                                                                           # proper ASCIItable format
 
@@ -194,7 +195,7 @@ class ASCIItable():
 # ------------------------------------------------------------------
   def head_write(self,
                  header = True):
-    """Write current header information (info + labels)"""
+    """Write current header information (info + labels)."""
     head = ['{}\theader'.format(len(self.info)+self.__IO__['labeled'])] if header else []
     head.append(self.info)
     if self.__IO__['labeled']:
@@ -205,7 +206,7 @@ class ASCIItable():
 
 # ------------------------------------------------------------------
   def head_getGeom(self):
-    """Interpret geom header"""
+    """Interpret geom header."""
     identifiers = {
             'grid':    ['a','b','c'],
             'size':    ['x','y','z'],
@@ -247,7 +248,7 @@ class ASCIItable():
   def labels_append(self,
                     what,
                     reset = False):
-    """Add item or list to existing set of labels (and switch on labeling)"""
+    """Add item or list to existing set of labels (and switch on labeling)."""
     if isinstance(what, (str, unicode)):
       self.tags += [self._removeCRLF(what)]
     else:
@@ -261,7 +262,7 @@ class ASCIItable():
 
 # ------------------------------------------------------------------
   def labels_clear(self):
-    """Delete existing labels and switch to no labeling"""
+    """Delete existing labels and switch to no labeling."""
     self.tags = []
     self.__IO__['labeled'] = False
 
@@ -392,7 +393,7 @@ class ASCIItable():
 # ------------------------------------------------------------------
   def info_append(self,
                   what):
-    """Add item or list to existing set of infos"""
+    """Add item or list to existing set of infos."""
     if isinstance(what, (str, unicode)):
       self.info += [self._removeCRLF(what)]
     else:
@@ -403,7 +404,7 @@ class ASCIItable():
 
 # ------------------------------------------------------------------
   def info_clear(self):
-    """Delete any info block"""
+    """Delete any info block."""
     self.info = []
 
 # ------------------------------------------------------------------
@@ -416,7 +417,7 @@ class ASCIItable():
 # ------------------------------------------------------------------
   def data_skipLines(self,
                      count):
-    """Wind forward by count number of lines"""
+    """Wind forward by count number of lines."""
     for i in range(count):
       alive = self.data_read()
 
@@ -426,7 +427,7 @@ class ASCIItable():
   def data_read(self,
                 advance = True,
                 respectLabels = True):
-    """Read next line (possibly buffered) and parse it into data array"""
+    """Read next line (possibly buffered) and parse it into data array."""
     self.line = self.__IO__['readBuffer'].pop(0) if len(self.__IO__['readBuffer']) > 0 \
            else self.__IO__['in'].readline().strip()                                                # take buffered content or get next data row from file
 
@@ -446,9 +447,11 @@ class ASCIItable():
 # ------------------------------------------------------------------
   def data_readArray(self,
                      labels = []):
-    """Read whole data of all (given) labels as numpy array"""
-    try:      self.data_rewind()                                                                    # try to wind back to start of data
-    except:   pass                                                                                  # assume/hope we are at data start already...
+    """Read whole data of all (given) labels as numpy array."""
+    try:
+      self.data_rewind()                                                                            # try to wind back to start of data
+    except IOError:
+      pass                                                                                          # assume/hope we are at data start already...
 
     if labels is None or labels == []:
       use = None                                                                                    # use all columns (and keep labels intact)
@@ -480,7 +483,7 @@ class ASCIItable():
 # ------------------------------------------------------------------
   def data_write(self,
                  delimiter = '\t'):
-    """Write current data array and report alive output back"""
+    """Write current data array and report alive output back."""
     if len(self.data) == 0: return True
 
     if isinstance(self.data[0],list):
@@ -492,16 +495,16 @@ class ASCIItable():
   def data_writeArray(self,
                       fmt = None,
                       delimiter = '\t'):
-    """Write whole numpy array data"""
+    """Write whole numpy array data."""
     for row in self.data:
       try:
         output = [fmt % value for value in row] if fmt else list(map(repr,row))
-      except:
+      except Exception:
         output = [fmt % row] if fmt else [repr(row)]
       
       try:
         self.__IO__['out'].write(delimiter.join(output) + '\n')
-      except:
+      except Exception:
         pass
 
 # ------------------------------------------------------------------
@@ -545,7 +548,7 @@ class ASCIItable():
                           grid,
                           type = 'i',
                           strict = False):
-    """Read microstructure data (from .geom format)"""
+    """Read microstructure data (from .geom format)."""
     def datatype(item):
       return int(item) if type.lower() == 'i' else float(item)
       
diff --git a/python/damask/dadf5.py b/python/damask/dadf5.py
index 7390724c8..69b19fefd 100644
--- a/python/damask/dadf5.py
+++ b/python/damask/dadf5.py
@@ -369,7 +369,7 @@ class DADF5():
       return f[self.get_dataset_location('orientation')[0]].attrs['Lattice'].astype('str')          # np.bytes_ to string
 
 
-  def read_dataset(self,path,c):
+  def read_dataset(self,path,c=0,plain=False):
     """
     Dataset for all points/cells.
     
@@ -402,7 +402,7 @@ class DADF5():
             a=a.reshape([a.shape[0],1])
           dataset[p,:] = a[u,:]
 
-    return dataset
+    return dataset if not plain else dataset.view(('float64',len(dataset.dtype.names)))
 
 
   def cell_coordinates(self):
@@ -620,7 +620,7 @@ class DADF5():
         raise ValueError
       
       return {
-              'data':  mechanics.deviator(x['data']),
+              'data':  mechanics.deviatoric_part(x['data']),
               'label': 's_{}'.format(x['label']),
               'meta':  {
                         'Unit':        x['meta']['Unit'],
diff --git a/python/damask/geom.py b/python/damask/geom.py
index 176d2bd12..6dfcda013 100644
--- a/python/damask/geom.py
+++ b/python/damask/geom.py
@@ -2,6 +2,7 @@ import os
 from io import StringIO
 
 import numpy as np
+from scipy import ndimage
 import vtk
 from vtk.util import numpy_support
 
@@ -10,380 +11,429 @@ from . import version
 
 
 class Geom():
-  """Geometry definition for grid solvers."""
+    """Geometry definition for grid solvers."""
 
-  def __init__(self,microstructure,size,origin=[0.0,0.0,0.0],homogenization=1,comments=[]):
-    """
-    New geometry definition from array of microstructures and size.
+    def __init__(self,microstructure,size,origin=[0.0,0.0,0.0],homogenization=1,comments=[]):
+        """
+        New geometry definition from array of microstructures and size.
 
-    Parameters
-    ----------
-    microstructure : numpy.ndarray
-        microstructure array (3D)
-    size : list or numpy.ndarray
-        physical size of the microstructure in meter.
-    origin : list or numpy.ndarray, optional
-        physical origin of the microstructure in meter.
-    homogenization : integer, optional
-        homogenization index.
-    comments : list of str, optional
-        comments lines.
+        Parameters
+        ----------
+        microstructure : numpy.ndarray
+            microstructure array (3D)
+        size : list or numpy.ndarray
+            physical size of the microstructure in meter.
+        origin : list or numpy.ndarray, optional
+            physical origin of the microstructure in meter.
+        homogenization : integer, optional
+            homogenization index.
+        comments : list of str, optional
+            comments lines.
 
-    """
-    self.__transforms__ = \
-    self.set_microstructure(microstructure)
-    self.set_size(size)
-    self.set_origin(origin)
-    self.set_homogenization(homogenization)
-    self.set_comments(comments)
-    
-
-  def __repr__(self):
-    """Basic information on geometry definition."""
-    return util.srepr([
-           'grid     a b c:      {}'.format(' x '.join(map(str,self.get_grid  ()))),
-           'size     x y z:      {}'.format(' x '.join(map(str,self.get_size  ()))),
-           'origin   x y z:      {}'.format('   '.join(map(str,self.get_origin()))),
-           'homogenization:      {}'.format(self.get_homogenization()),
-           '# microstructures:   {}'.format(len(np.unique(self.microstructure))),
-           'max microstructure:  {}'.format(np.nanmax(self.microstructure)),
-          ])
-
-  def update(self,microstructure=None,size=None,origin=None,rescale=False):
-    """
-    Updates microstructure and size.
-
-    Parameters
-    ----------
-    microstructure : numpy.ndarray, optional
-        microstructure array (3D).
-    size : list or numpy.ndarray, optional
-        physical size of the microstructure in meter.
-    origin : list or numpy.ndarray, optional
-        physical origin of the microstructure in meter.
-    rescale : bool, optional
-        ignore size parameter and rescale according to change of grid points.
-
-    """
-    grid_old    = self.get_grid()
-    size_old    = self.get_size()
-    origin_old  = self.get_origin()
-    unique_old  = len(np.unique(self.microstructure))
-    max_old     = np.nanmax(self.microstructure)
-    
-    if size is not None and rescale:
-      raise ValueError('Either set size explicitly or rescale automatically')
-
-    self.set_microstructure(microstructure)
-    self.set_origin(origin)
-
-    if size is not None:
-      self.set_size(size)
-    elif rescale:
-      self.set_size(self.get_grid()/grid_old*self.size)
-
-    message = ['grid     a b c:      {}'.format(' x '.join(map(str,grid_old)))]
-    if np.any(grid_old != self.get_grid()):
-      message[-1] = util.delete(message[-1])
-      message.append(util.emph('grid     a b c:      {}'.format(' x '.join(map(str,self.get_grid())))))
-
-    message.append('size     x y z:      {}'.format(' x '.join(map(str,size_old))))
-    if np.any(size_old != self.get_size()):
-      message[-1] = util.delete(message[-1])
-      message.append(util.emph('size     x y z:      {}'.format(' x '.join(map(str,self.get_size())))))
-
-    message.append('origin   x y z:      {}'.format('   '.join(map(str,origin_old))))
-    if np.any(origin_old != self.get_origin()):
-      message[-1] = util.delete(message[-1])
-      message.append(util.emph('origin   x y z:      {}'.format('   '.join(map(str,self.get_origin())))))
-
-    message.append('homogenization:      {}'.format(self.get_homogenization()))
-
-    message.append('# microstructures:   {}'.format(unique_old))
-    if unique_old != len(np.unique(self.microstructure)):
-      message[-1] = util.delete(message[-1])
-      message.append(util.emph('# microstructures:   {}'.format(len(np.unique(self.microstructure)))))
-
-    message.append('max microstructure:  {}'.format(max_old))
-    if max_old != np.nanmax(self.microstructure):
-      message[-1] = util.delete(message[-1])
-      message.append(util.emph('max microstructure:  {}'.format(np.nanmax(self.microstructure))))
-    
-    return util.return_message(message)
-
-  def set_comments(self,comments):
-    """
-    Replaces all existing comments.
-
-    Parameters
-    ----------
-    comments : list of str
-        new comments.
-
-    """
-    self.comments = []
-    self.add_comments(comments)
-    
-  def add_comments(self,comments):
-    """
-    Appends comments to existing comments.
-
-    Parameters
-    ----------
-    comments : list of str
-        new comments.
-
-    """
-    self.comments += [str(c) for c in comments] if isinstance(comments,list) else [str(comments)]
-
-  def set_microstructure(self,microstructure):
-    """
-    Replaces the existing microstructure representation.
-
-    Parameters
-    ----------
-    microstructure : numpy.ndarray
-        microstructure array (3D).
-
-    """
-    if microstructure is not None:
-      if len(microstructure.shape) != 3:
-        raise ValueError('Invalid microstructure shape {}'.format(*microstructure.shape))
-      elif microstructure.dtype not in np.sctypes['float'] + np.sctypes['int']:
-        raise TypeError('Invalid data type {} for microstructure'.format(microstructure.dtype))
-      else:
-        self.microstructure = np.copy(microstructure)
-
-  def set_size(self,size):
-    """
-    Replaces the existing size information.
-
-    Parameters
-    ----------
-    size : list or numpy.ndarray
-        physical size of the microstructure in meter.
-
-    """
-    if size is None:
-      grid = np.asarray(self.microstructure.shape)
-      self.size = grid/np.max(grid)
-    else:
-      if len(size) != 3 or any(np.array(size)<=0):
-        raise ValueError('Invalid size {}'.format(*size))
-      else:
-        self.size = np.array(size)
-
-  def set_origin(self,origin):
-    """
-    Replaces the existing origin information.
-
-    Parameters
-    ----------
-    origin : list or numpy.ndarray
-        physical origin of the microstructure in meter
-
-    """
-    if origin is not None:
-      if len(origin) != 3:
-        raise ValueError('Invalid origin {}'.format(*origin))
-      else:
-        self.origin = np.array(origin)
-
-  def set_homogenization(self,homogenization):
-    """
-    Replaces the existing homogenization index.
-
-    Parameters
-    ----------
-    homogenization : integer
-        homogenization index
-
-    """
-    if homogenization is not None:
-      if not isinstance(homogenization,int) or homogenization < 1:
-        raise TypeError('Invalid homogenization {}'.format(homogenization))
-      else:
-        self.homogenization = homogenization
-
-
-  def get_microstructure(self):
-    """Return the microstructure representation."""
-    return np.copy(self.microstructure)
-
-  def get_size(self):
-    """Return the physical size in meter."""
-    return np.copy(self.size)
-
-  def get_origin(self):
-    """Return the origin in meter."""
-    return np.copy(self.origin)
-
-  def get_grid(self):
-    """Return the grid discretization."""
-    return np.array(self.microstructure.shape)
-
-  def get_homogenization(self):
-    """Return the homogenization index."""
-    return self.homogenization
-
-  def get_comments(self):
-    """Return the comments."""
-    return self.comments[:]
-
-  def get_header(self):
-    """Return the full header (grid, size, origin, homogenization, comments)."""
-    header =  ['{} header'.format(len(self.comments)+4)] + self.comments
-    header.append('grid   a {} b {} c {}'.format(*self.get_grid()))
-    header.append('size   x {} y {} z {}'.format(*self.get_size()))
-    header.append('origin x {} y {} z {}'.format(*self.get_origin()))
-    header.append('homogenization {}'.format(self.get_homogenization()))
-    return header
+        """
+        self.set_microstructure(microstructure)
+        self.set_size(size)
+        self.set_origin(origin)
+        self.set_homogenization(homogenization)
+        self.set_comments(comments)
       
-  @classmethod
-  def from_file(cls,fname):
-    """
-    Reads a geom file.
 
-    Parameters
-    ----------
-    fname : str or file handle
-        geometry file to read.
+    def __repr__(self):
+        """Basic information on geometry definition."""
+        return util.srepr([
+               'grid     a b c:      {}'.format(' x '.join(map(str,self.get_grid  ()))),
+               'size     x y z:      {}'.format(' x '.join(map(str,self.get_size  ()))),
+               'origin   x y z:      {}'.format('   '.join(map(str,self.get_origin()))),
+               'homogenization:      {}'.format(self.get_homogenization()),
+               '# microstructures:   {}'.format(len(np.unique(self.microstructure))),
+               'max microstructure:  {}'.format(np.nanmax(self.microstructure)),
+              ])
 
-    """
-    with (open(fname) if isinstance(fname,str) else fname) as f:
-      f.seek(0)
-      header_length,keyword = f.readline().split()[:2]
-      header_length = int(header_length)
-      content = f.readlines()
+    def update(self,microstructure=None,size=None,origin=None,rescale=False):
+        """
+        Updates microstructure and size.
 
-    if not keyword.startswith('head') or header_length < 3:
-      raise TypeError('Header length information missing or invalid')
+        Parameters
+        ----------
+        microstructure : numpy.ndarray, optional
+            microstructure array (3D).
+        size : list or numpy.ndarray, optional
+            physical size of the microstructure in meter.
+        origin : list or numpy.ndarray, optional
+            physical origin of the microstructure in meter.
+        rescale : bool, optional
+            ignore size parameter and rescale according to change of grid points.
 
-    comments = [] 
-    for i,line in enumerate(content[:header_length]):
-      items = line.lower().strip().split()
-      key = items[0] if len(items) > 0 else ''
-      if   key == 'grid':
-        grid   = np.array([  int(dict(zip(items[1::2],items[2::2]))[i]) for i in ['a','b','c']])
-      elif key == 'size':
-        size   = np.array([float(dict(zip(items[1::2],items[2::2]))[i]) for i in ['x','y','z']])
-      elif key == 'origin':
-        origin = np.array([float(dict(zip(items[1::2],items[2::2]))[i]) for i in ['x','y','z']])
-      elif key == 'homogenization':
-        homogenization = int(items[1])
-      else:
-        comments.append(line.strip())
+        """
+        grid_old    = self.get_grid()
+        size_old    = self.get_size()
+        origin_old  = self.get_origin()
+        unique_old  = len(np.unique(self.microstructure))
+        max_old     = np.nanmax(self.microstructure)
+        
+        if size is not None and rescale:
+            raise ValueError('Either set size explicitly or rescale automatically')
 
-    microstructure = np.empty(grid.prod())                                                          # initialize as flat array
-    i = 0
-    for line in content[header_length:]:
-      items = line.split()
-      if len(items) == 3:
-        if   items[1].lower() == 'of':
-          items = np.ones(int(items[0]))*float(items[2])
-        elif items[1].lower() == 'to':
-          items = np.linspace(int(items[0]),int(items[2]),
-                              abs(int(items[2])-int(items[0]))+1,dtype=float)
-        else:                          items = list(map(float,items))
-      else:                            items = list(map(float,items))
+        self.set_microstructure(microstructure)
+        self.set_origin(origin)
+
+        if size is not None:
+            self.set_size(size)
+        elif rescale:
+             self.set_size(self.get_grid()/grid_old*self.size)
+
+        message = ['grid     a b c:      {}'.format(' x '.join(map(str,grid_old)))]
+        if np.any(grid_old != self.get_grid()):
+            message[-1] = util.delete(message[-1])
+            message.append(util.emph('grid     a b c:      {}'.format(' x '.join(map(str,self.get_grid())))))
+
+        message.append('size     x y z:      {}'.format(' x '.join(map(str,size_old))))
+        if np.any(size_old != self.get_size()):
+            message[-1] = util.delete(message[-1])
+            message.append(util.emph('size     x y z:      {}'.format(' x '.join(map(str,self.get_size())))))
+
+        message.append('origin   x y z:      {}'.format('   '.join(map(str,origin_old))))
+        if np.any(origin_old != self.get_origin()):
+            message[-1] = util.delete(message[-1])
+            message.append(util.emph('origin   x y z:      {}'.format('   '.join(map(str,self.get_origin())))))
+
+        message.append('homogenization:      {}'.format(self.get_homogenization()))
+
+        message.append('# microstructures:   {}'.format(unique_old))
+        if unique_old != len(np.unique(self.microstructure)):
+            message[-1] = util.delete(message[-1])
+            message.append(util.emph('# microstructures:   {}'.format(len(np.unique(self.microstructure)))))
+
+        message.append('max microstructure:  {}'.format(max_old))
+        if max_old != np.nanmax(self.microstructure):
+            message[-1] = util.delete(message[-1])
+            message.append(util.emph('max microstructure:  {}'.format(np.nanmax(self.microstructure))))
+        
+        return util.return_message(message)
+
+    def set_comments(self,comments):
+        """
+        Replaces all existing comments.
+
+        Parameters
+        ----------
+        comments : list of str
+            new comments.
+
+        """
+        self.comments = []
+        self.add_comments(comments)
       
-      microstructure[i:i+len(items)] = items
-      i += len(items)
+    def add_comments(self,comments):
+        """
+        Appends comments to existing comments.
+
+        Parameters
+        ----------
+        comments : list of str
+            new comments.
+
+        """
+        self.comments += [str(c) for c in comments] if isinstance(comments,list) else [str(comments)]
+
+    def set_microstructure(self,microstructure):
+        """
+        Replaces the existing microstructure representation.
+
+        Parameters
+        ----------
+        microstructure : numpy.ndarray
+            microstructure array (3D).
+
+        """
+        if microstructure is not None:
+            if len(microstructure.shape) != 3:
+                raise ValueError('Invalid microstructure shape {}'.format(*microstructure.shape))
+            elif microstructure.dtype not in np.sctypes['float'] + np.sctypes['int']:
+                raise TypeError('Invalid data type {} for microstructure'.format(microstructure.dtype))
+            else:
+                self.microstructure = np.copy(microstructure)
+
+    def set_size(self,size):
+        """
+        Replaces the existing size information.
+
+        Parameters
+        ----------
+        size : list or numpy.ndarray
+            physical size of the microstructure in meter.
+
+        """
+        if size is None:
+            grid = np.asarray(self.microstructure.shape)
+            self.size = grid/np.max(grid)
+        else:
+            if len(size) != 3 or any(np.array(size)<=0):
+                raise ValueError('Invalid size {}'.format(*size))
+            else:
+                self.size = np.array(size)
+
+    def set_origin(self,origin):
+        """
+        Replaces the existing origin information.
+
+        Parameters
+        ----------
+        origin : list or numpy.ndarray
+            physical origin of the microstructure in meter
+
+        """
+        if origin is not None:
+            if len(origin) != 3:
+                raise ValueError('Invalid origin {}'.format(*origin))
+            else:
+                self.origin = np.array(origin)
+
+    def set_homogenization(self,homogenization):
+        """
+        Replaces the existing homogenization index.
+
+        Parameters
+        ----------
+        homogenization : integer
+            homogenization index
+
+        """
+        if homogenization is not None:
+            if not isinstance(homogenization,int) or homogenization < 1:
+                raise TypeError('Invalid homogenization {}'.format(homogenization))
+            else:
+                self.homogenization = homogenization
+
+
+    def get_microstructure(self):
+        """Return the microstructure representation."""
+        return np.copy(self.microstructure)
+
+    def get_size(self):
+        """Return the physical size in meter."""
+        return np.copy(self.size)
+
+    def get_origin(self):
+        """Return the origin in meter."""
+        return np.copy(self.origin)
+
+    def get_grid(self):
+        """Return the grid discretization."""
+        return np.array(self.microstructure.shape)
+
+    def get_homogenization(self):
+        """Return the homogenization index."""
+        return self.homogenization
+
+    def get_comments(self):
+        """Return the comments."""
+        return self.comments[:]
+
+    def get_header(self):
+        """Return the full header (grid, size, origin, homogenization, comments)."""
+        header =  ['{} header'.format(len(self.comments)+4)] + self.comments
+        header.append('grid   a {} b {} c {}'.format(*self.get_grid()))
+        header.append('size   x {} y {} z {}'.format(*self.get_size()))
+        header.append('origin x {} y {} z {}'.format(*self.get_origin()))
+        header.append('homogenization {}'.format(self.get_homogenization()))
+        return header
+        
+    @classmethod
+    def from_file(cls,fname):
+        """
+        Reads a geom file.
+
+        Parameters
+        ----------
+        fname : str or file handle
+            geometry file to read.
+
+        """
+        with (open(fname) if isinstance(fname,str) else fname) as f:
+            f.seek(0)
+            header_length,keyword = f.readline().split()[:2]
+            header_length = int(header_length)
+            content = f.readlines()
+
+        if not keyword.startswith('head') or header_length < 3:
+            raise TypeError('Header length information missing or invalid')
+
+        comments = [] 
+        for i,line in enumerate(content[:header_length]):
+            items = line.lower().strip().split()
+            key = items[0] if len(items) > 0 else ''
+            if   key == 'grid':
+                grid   = np.array([  int(dict(zip(items[1::2],items[2::2]))[i]) for i in ['a','b','c']])
+            elif key == 'size':
+                size   = np.array([float(dict(zip(items[1::2],items[2::2]))[i]) for i in ['x','y','z']])
+            elif key == 'origin':
+                origin = np.array([float(dict(zip(items[1::2],items[2::2]))[i]) for i in ['x','y','z']])
+            elif key == 'homogenization':
+                homogenization = int(items[1])
+            else:
+                comments.append(line.strip())
+
+        microstructure = np.empty(grid.prod())                                                      # initialize as flat array
+        i = 0
+        for line in content[header_length:]:
+            items = line.split()
+            if len(items) == 3:
+                if   items[1].lower() == 'of':
+                    items = np.ones(int(items[0]))*float(items[2])
+                elif items[1].lower() == 'to':
+                    items = np.linspace(int(items[0]),int(items[2]),
+                                        abs(int(items[2])-int(items[0]))+1,dtype=float)
+                else:                        items = list(map(float,items))
+            else:                            items = list(map(float,items))
+            microstructure[i:i+len(items)] = items
+            i += len(items)
+        
+        if i != grid.prod():
+            raise TypeError('Invalid file: expected {} entries,found {}'.format(grid.prod(),i))
+        
+        microstructure = microstructure.reshape(grid,order='F')
+        if not np.any(np.mod(microstructure.flatten(),1) != 0.0):                                   # no float present
+            microstructure = microstructure.astype('int')
+        
+        return cls(microstructure.reshape(grid),size,origin,homogenization,comments)
+
+
+    def to_file(self,fname):
+        """
+        Writes a geom file.
+
+        Parameters
+        ----------
+        fname : str or file handle
+            geometry file to write.
+
+        """
+        header = self.get_header()
+        grid   = self.get_grid()
+        format_string = '%g' if self.microstructure in np.sctypes['float'] else \
+                        '%{}i'.format(1+int(np.floor(np.log10(np.nanmax(self.microstructure)))))
+        np.savetxt(fname,
+                   self.microstructure.reshape([grid[0],np.prod(grid[1:])],order='F').T,
+                   header='\n'.join(header), fmt=format_string, comments='')
+                 
+    def to_vtk(self,fname=None):
+        """
+        Generates vtk file.
+
+        Parameters
+        ----------
+        fname : str, optional
+            vtk file to write. If no file is given, a string is returned.
+
+        """
+        grid = self.get_grid() + np.ones(3,dtype=int)
+        size = self.get_size()
+        origin = self.get_origin()
+
+        coords = [
+                  np.linspace(0,size[0],grid[0]) + origin[0],
+                  np.linspace(0,size[1],grid[1]) + origin[1],
+                  np.linspace(0,size[2],grid[2]) + origin[2]
+                 ]
+        
+        rGrid = vtk.vtkRectilinearGrid()
+        coordArray = [vtk.vtkDoubleArray(),vtk.vtkDoubleArray(),vtk.vtkDoubleArray()]
+
+        rGrid.SetDimensions(*grid)
+        for d,coord in enumerate(coords):
+            for c in coord:
+                coordArray[d].InsertNextValue(c)
+
+        rGrid.SetXCoordinates(coordArray[0])
+        rGrid.SetYCoordinates(coordArray[1])
+        rGrid.SetZCoordinates(coordArray[2])
+        
+        ms = numpy_support.numpy_to_vtk(num_array=self.microstructure.flatten(order='F'),
+                                        array_type=vtk.VTK_INT if self.microstructure.dtype == int else vtk.VTK_FLOAT)
+        ms.SetName('microstructure')
+        rGrid.GetCellData().AddArray(ms)
+
+
+        if fname is None:
+            writer = vtk.vtkDataSetWriter()
+            writer.SetHeader('damask.Geom '+version)
+            writer.WriteToOutputStringOn()
+        else:
+            writer = vtk.vtkXMLRectilinearGridWriter()
+            writer.SetCompressorTypeToZLib()
+            writer.SetDataModeToBinary()
+            
+            ext = os.path.splitext(fname)[1]
+            if ext == '':
+                name = fname + '.' + writer.GetDefaultFileExtension()
+            elif ext == writer.GetDefaultFileExtension():
+                name = fname
+            else:
+                raise ValueError("unknown extension {}".format(ext))
+            writer.SetFileName(name)
     
-    if i != grid.prod():
-      raise TypeError('Invalid file: expected {} entries,found {}'.format(grid.prod(),i))
-    
-    microstructure = microstructure.reshape(grid,order='F')
-    if not np.any(np.mod(microstructure.flatten(),1) != 0.0):                                       # no float present
-      microstructure = microstructure.astype('int')
-    
-    return cls(microstructure.reshape(grid),size,origin,homogenization,comments)
+        writer.SetInputData(rGrid)
+        writer.Write()
 
-  def to_file(self,fname):
-    """
-    Writes a geom file.
+        if fname is None: return writer.GetOutputString()
 
-    Parameters
-    ----------
-    fname : str or file handle
-        geometry file to write.
-
-    """
-    header = self.get_header()
-    grid   = self.get_grid()
-    format_string = '%{}i'.format(1+int(np.floor(np.log10(np.nanmax(self.microstructure))))) if self.microstructure.dtype == int \
-               else '%g'
-    np.savetxt(fname,
-               self.microstructure.reshape([grid[0],np.prod(grid[1:])],order='F').T,
-               header='\n'.join(header), fmt=format_string, comments='')
+                 
+    def show(self):
+        """Show raw content (as in file)."""
+        f=StringIO()
+        self.to_file(f)
+        f.seek(0)
+        return ''.join(f.readlines())
 
 
-               
-  def to_vtk(self,fname=None):
-    """
-    Generates vtk file.
+    def mirror(self,directions,reflect=False):
+        """
+        Mirror microstructure along given directions.
 
-    Parameters
-    ----------
-    fname : str, optional
-        vtk file to write. If no file is given, a string is returned.
+        Parameters
+        ----------
+        directions : iterable containing str
+            direction(s) along which the microstructure is mirrored. Valid entries are 'x', 'y', 'z'.
+        reflect : bool, optional
+            reflect (include) outermost layers.
 
-    """
-    grid = self.get_grid() + np.ones(3,dtype=int)
-    size = self.get_size()
-    origin = self.get_origin()
+        """
+        valid = {'x','y','z'}
+        if not all(isinstance(d, str) for d in directions):
+            raise TypeError('Directions are not of type str.')
+        elif not set(directions).issubset(valid):
+            raise ValueError('Invalid direction specified {}'.format(*set(directions).difference(valid)))
 
-    coords = [
-              np.linspace(0,size[0],grid[0]) + origin[0],
-              np.linspace(0,size[1],grid[1]) + origin[1],
-              np.linspace(0,size[2],grid[2]) + origin[2]
-             ]
-    
-    rGrid = vtk.vtkRectilinearGrid()
-    coordArray = [vtk.vtkDoubleArray(),vtk.vtkDoubleArray(),vtk.vtkDoubleArray()]
+        limits = [None,None] if reflect else [-2,0]
+        ms = self.get_microstructure()
 
-    rGrid.SetDimensions(*grid)
-    for d,coord in enumerate(coords):
-      for c in coord:
-        coordArray[d].InsertNextValue(c)
-
-    rGrid.SetXCoordinates(coordArray[0])
-    rGrid.SetYCoordinates(coordArray[1])
-    rGrid.SetZCoordinates(coordArray[2])
-    
-    ms = numpy_support.numpy_to_vtk(num_array=self.microstructure.flatten(order='F'),
-                                    array_type=vtk.VTK_INT if self.microstructure.dtype == int else vtk.VTK_FLOAT)
-    ms.SetName('microstructure')
-    rGrid.GetCellData().AddArray(ms)
+        if 'z' in directions:
+            ms = np.concatenate([ms,ms[:,:,limits[0]:limits[1]:-1]],2)
+        if 'y' in directions:
+            ms = np.concatenate([ms,ms[:,limits[0]:limits[1]:-1,:]],1)
+        if 'x' in directions:
+            ms = np.concatenate([ms,ms[limits[0]:limits[1]:-1,:,:]],0)
+     
+        return self.update(ms,rescale=True)
+        #self.add_comments('tbd')
 
 
-    if fname is None:
-      writer = vtk.vtkDataSetWriter()
-      writer.SetHeader('damask.Geom '+version)
-      writer.WriteToOutputStringOn()
-    else:
-      writer = vtk.vtkXMLRectilinearGridWriter()
-      writer.SetCompressorTypeToZLib()
-      writer.SetDataModeToBinary()
-      
-      ext = os.path.splitext(fname)[1]
-      if ext == '':
-        name = fname + '.' + writer.GetDefaultFileExtension()
-      elif ext == writer.GetDefaultFileExtension():
-        name = fname
-      else:
-        raise ValueError("unknown extension {}".format(ext))
-      writer.SetFileName(name)
-  
-    writer.SetInputData(rGrid)
-    writer.Write()
+    def clean(self,stencil=3):
+        """
+        Smooth microstructure by selecting most frequent index within given stencil at each location.
 
-    if fname is None: return writer.GetOutputString()
+        Parameters
+        ----------
+        stencil : int, optional
+            size of smoothing stencil.
 
-               
-  def show(self):
-    """Show raw content (as in file)."""
-    f=StringIO()
-    self.to_file(f)
-    f.seek(0)
-    return ''.join(f.readlines())
+        """
+        def mostFrequent(arr):
+            unique, inverse = np.unique(arr, return_inverse=True)
+            return unique[np.argmax(np.bincount(inverse))]
+
+        return self.update(ndimage.filters.generic_filter(self.microstructure,
+                                                          mostFrequent,
+                                                          size=(stencil,)*3).astype(self.microstructure.dtype))
+        #self.add_comments('tbd')
diff --git a/python/damask/mechanics.py b/python/damask/mechanics.py
index 436fbe091..476682380 100644
--- a/python/damask/mechanics.py
+++ b/python/damask/mechanics.py
@@ -48,10 +48,10 @@ def strain_tensor(F,t,m):
     
     if   m > 0.0:
         eps = 1.0/(2.0*abs(m)) * (+ np.matmul(n,np.einsum('ij,ikj->ijk',w**m,n)) 
-                                  - np.broadcast_to(np.ones(3),[F_.shape[0],3]))
+                                  - np.broadcast_to(np.eye(3),[F_.shape[0],3,3]))
     elif m < 0.0:
         eps = 1.0/(2.0*abs(m)) * (- np.matmul(n,np.einsum('ij,ikj->ijk',w**m,n))
-                                  + np.broadcast_to(np.ones(3),[F_.shape[0],3]))
+                                  + np.broadcast_to(np.eye(3),[F_.shape[0],3,3]))
     else:
         eps = np.matmul(n,np.einsum('ij,ikj->ijk',0.5*np.log(w),n))
       
@@ -190,7 +190,7 @@ def rotational_part(x):
       Tensor of which the rotational part is computed.
 
     """
-    return __polar_decomposition(x,'R')
+    return __polar_decomposition(x,'R')[0]
 
 
 def left_stretch(x):
@@ -203,7 +203,7 @@ def left_stretch(x):
       Tensor of which the left stretch is computed.
 
     """
-    return __polar_decomposition(x,'V')
+    return __polar_decomposition(x,'V')[0]
   
   
 def right_stretch(x):
@@ -216,7 +216,7 @@ def right_stretch(x):
       Tensor of which the right stretch is computed.
 
     """
-    return __polar_decomposition(x,'U')
+    return __polar_decomposition(x,'U')[0]
 
 
 def __polar_decomposition(x,requested):
@@ -227,7 +227,7 @@ def __polar_decomposition(x,requested):
     ----------
     x : numpy.array of shape (:,3,3) or (3,3)
       Tensor of which the singular values are computed.
-    requested : list of str
+    requested : iterable of str
       Requested outputs: ‘R’ for the rotation tensor, 
       ‘V’ for left stretch tensor and ‘U’ for right stretch tensor.
 
diff --git a/python/damask/solver/marc.py b/python/damask/solver/marc.py
index 5e728545d..971b2226b 100644
--- a/python/damask/solver/marc.py
+++ b/python/damask/solver/marc.py
@@ -79,9 +79,9 @@ class Marc(Solver):
     exitnumber = -1
     fid_out = open(outFile,'r')
     for line in fid_out:
-      if (string.find(line,'tress iteration') is not -1):
+      if (string.find(line,'tress iteration') != -1):
         print(line)
-      elif (string.find(line,'Exit number') is not -1):
+      elif (string.find(line,'Exit number')   != -1):
         substr = line[string.find(line,'Exit number'):len(line)]
         exitnumber = int(substr[12:16])
 
diff --git a/python/damask/test/test.py b/python/damask/test.py
similarity index 97%
rename from python/damask/test/test.py
rename to python/damask/test.py
index e7f2da14a..b1729548d 100644
--- a/python/damask/test/test.py
+++ b/python/damask/test.py
@@ -1,10 +1,8 @@
-# -*- coding: UTF-8 no BOM -*-
-
 import os,sys,shutil
 import logging,logging.config
 import damask
 import numpy as np
-from collections import Iterable
+from collections.abc import Iterable
 from optparse import OptionParser
 
 class Test():
@@ -17,7 +15,7 @@ class Test():
   variants = []
   
   def __init__(self, **kwargs):
-
+    """New test."""
     defaults = {'description': '',
                 'keep':          False,
                 'accept':        False,
@@ -120,22 +118,22 @@ class Test():
     """Delete directory tree containing current results."""
     try:
       shutil.rmtree(self.dirCurrent())
-    except:
+    except FileNotFoundError:
       logging.warning('removal of directory "{}" not possible...'.format(self.dirCurrent()))
 
     try:
       os.mkdir(self.dirCurrent())
       return True
-    except:
+    except FileExistsError:
       logging.critical('creation of directory "{}" failed.'.format(self.dirCurrent()))
       return False
     
   def prepareAll(self):
-    """Do all necessary preparations for the whole test"""
+    """Do all necessary preparations for the whole test."""
     return True
 
   def prepare(self,variant):
-    """Do all necessary preparations for the run of each test variant"""
+    """Do all necessary preparations for the run of each test variant."""
     return True
 
 
@@ -207,9 +205,9 @@ class Test():
     for source,target in zip(list(map(mapA,A)),list(map(mapB,B))):
       try:
         shutil.copy2(source,target)
-      except:
+      except FileNotFoundError:
         logging.critical('error copying {} to {}'.format(source,target))
-        raise
+        raise FileNotFoundError
 
 
   def copy_Reference2Current(self,sourcefiles=[],targetfiles=[]):
@@ -218,9 +216,9 @@ class Test():
     for i,f in enumerate(sourcefiles):
       try:
         shutil.copy2(self.fileInReference(f),self.fileInCurrent(targetfiles[i]))
-      except:
+      except FileNotFoundError:
         logging.critical('Reference2Current: Unable to copy file "{}"'.format(f))
-        raise
+        raise FileNotFoundError
 
 
   def copy_Base2Current(self,sourceDir,sourcefiles=[],targetfiles=[]):
@@ -230,10 +228,10 @@ class Test():
     for i,f in enumerate(sourcefiles):
       try:
         shutil.copy2(os.path.join(source,f),self.fileInCurrent(targetfiles[i]))
-      except:
+      except FileNotFoundError:
         logging.error(os.path.join(source,f))
         logging.critical('Base2Current: Unable to copy file "{}"'.format(f))
-        raise
+        raise FileNotFoundError
 
 
   def copy_Current2Reference(self,sourcefiles=[],targetfiles=[]):
@@ -242,9 +240,9 @@ class Test():
     for i,f in enumerate(sourcefiles):
       try:
         shutil.copy2(self.fileInCurrent(f),self.fileInReference(targetfiles[i]))
-      except:
+      except FileNotFoundError:
         logging.critical('Current2Reference: Unable to copy file "{}"'.format(f))
-        raise
+        raise FileNotFoundError
 
 
   def copy_Proof2Current(self,sourcefiles=[],targetfiles=[]):
@@ -253,9 +251,9 @@ class Test():
     for i,f in enumerate(sourcefiles):
       try:
         shutil.copy2(self.fileInProof(f),self.fileInCurrent(targetfiles[i]))
-      except:
+      except FileNotFoundError:
         logging.critical('Proof2Current: Unable to copy file "{}"'.format(f))
-        raise
+        raise FileNotFoundError
 
 
   def copy_Current2Current(self,sourcefiles=[],targetfiles=[]):
@@ -263,9 +261,10 @@ class Test():
     for i,f in enumerate(sourcefiles):
       try:
         shutil.copy2(self.fileInReference(f),self.fileInCurrent(targetfiles[i]))
-      except:
+      except FileNotFoundError:
         logging.critical('Current2Current: Unable to copy file "{}"'.format(f))
-        raise
+        raise FileNotFoundError
+
 
   def execute_inCurrentDir(self,cmd,streamIn=None,env=None):
 
@@ -439,7 +438,7 @@ class Test():
                      stdTol = 1.0e-6,
                      preFilter = 1.0e-9):
     """
-    Calculate statistics of tables
+    Calculate statistics of tables.
 
     threshold can be used to ignore small values (a negative number disables this feature)
     """
@@ -492,7 +491,7 @@ class Test():
                      rtol    = 1e-5,
                      atol    = 1e-8,
                      debug   = False):
-    """Compare multiple tables with np.allclose"""
+    """Compare multiple tables with np.allclose."""
     if not (isinstance(files, Iterable) and not isinstance(files, str)):       # check whether list of files is requested
       files = [str(files)]
 
diff --git a/python/damask/test/__init__.py b/python/damask/test/__init__.py
deleted file mode 100644
index a8d5d5034..000000000
--- a/python/damask/test/__init__.py
+++ /dev/null
@@ -1,3 +0,0 @@
-"""Test functionality."""
-
-from .test import Test      # noqa