diff --git a/python/damask/VERSION b/python/damask/VERSION
index 750043c40..8d2c8c56d 100644
--- a/python/damask/VERSION
+++ b/python/damask/VERSION
@@ -1 +1 @@
-v3.0.0-alpha5-518-g4fa97b9a3
+v3.0.0-alpha5-545-gad74f5dbe
diff --git a/python/damask/_colormap.py b/python/damask/_colormap.py
index 93bd83cdc..005cf80d6 100644
--- a/python/damask/_colormap.py
+++ b/python/damask/_colormap.py
@@ -47,27 +47,32 @@ class Colormap(mpl.colors.ListedColormap):
 
     """
 
-    def __eq__(self, other: object) -> bool:
+    def __eq__(self,
+               other: object) -> bool:
         """Test equality of colormaps."""
         if not isinstance(other, Colormap):
             return NotImplemented
         return         len(self.colors) == len(other.colors) \
            and bool(np.all(self.colors  ==     other.colors))
 
-    def __add__(self, other: 'Colormap') -> 'Colormap':
+    def __add__(self,
+                other: 'Colormap') -> 'Colormap':
         """Concatenate."""
         return Colormap(np.vstack((self.colors,other.colors)),
                         f'{self.name}+{other.name}')
 
-    def __iadd__(self, other: 'Colormap') -> 'Colormap':
+    def __iadd__(self,
+                 other: 'Colormap') -> 'Colormap':
         """Concatenate (in-place)."""
         return self.__add__(other)
 
-    def __mul__(self, factor: int) -> 'Colormap':
+    def __mul__(self,
+                factor: int) -> 'Colormap':
         """Repeat."""
         return Colormap(np.vstack([self.colors]*factor),f'{self.name}*{factor}')
 
-    def __imul__(self, factor: int) -> 'Colormap':
+    def __imul__(self,
+                 factor: int) -> 'Colormap':
         """Repeat (in-place)."""
         return self.__mul__(factor)
 
@@ -161,7 +166,8 @@ class Colormap(mpl.colors.ListedColormap):
 
 
     @staticmethod
-    def from_predefined(name: str, N: int = 256) -> 'Colormap':
+    def from_predefined(name: str,
+                        N: int = 256) -> 'Colormap':
         """
         Select from a set of predefined colormaps.
 
@@ -260,10 +266,8 @@ class Colormap(mpl.colors.ListedColormap):
         l,r = (field[mask].min(),field[mask].max()) if bounds is None else \
               (bounds[0],bounds[1])
 
-        delta,avg = r-l,0.5*abs(r+l)
-
-        if abs(delta) * 1e8 <= avg:                                                                 # delta is similar to numerical noise
-            l,r = l-0.5*avg*np.sign(delta),r+0.5*avg*np.sign(delta),                                # extend range to have actual data centered within
+        if abs(delta := r-l) * 1e8 <= (avg := 0.5*abs(r+l)):                                        # delta is similar to numerical noise
+            l,r = (l-0.5*avg*np.sign(delta),r+0.5*avg*np.sign(delta))                               # extend range to have actual data centered within
 
         return Image.fromarray(
             (np.dstack((
@@ -275,7 +279,8 @@ class Colormap(mpl.colors.ListedColormap):
             mode='RGBA')
 
 
-    def reversed(self, name: str = None) -> 'Colormap':
+    def reversed(self,
+                 name: str = None) -> 'Colormap':
         """
         Reverse.
 
@@ -296,7 +301,7 @@ class Colormap(mpl.colors.ListedColormap):
         >>> damask.Colormap.from_predefined('stress').reversed()
 
         """
-        rev = super(Colormap,self).reversed(name)
+        rev = super().reversed(name)
         return Colormap(np.array(rev.colors),rev.name[:-4] if rev.name.endswith('_r_r') else rev.name)
 
 
@@ -328,7 +333,8 @@ class Colormap(mpl.colors.ListedColormap):
             return fname
 
 
-    def save_paraview(self, fname: FileHandle = None):
+    def save_paraview(self,
+                      fname: FileHandle = None):
         """
         Save as JSON file for use in Paraview.
 
@@ -355,7 +361,8 @@ class Colormap(mpl.colors.ListedColormap):
         fhandle.write('\n')
 
 
-    def save_ASCII(self, fname: FileHandle = None):
+    def save_ASCII(self,
+                   fname: FileHandle = None):
         """
         Save as ASCII file.
 
@@ -390,7 +397,8 @@ class Colormap(mpl.colors.ListedColormap):
         self._get_file_handle(fname,'.legend').write(GOM_str)
 
 
-    def save_gmsh(self, fname: FileHandle = None):
+    def save_gmsh(self,
+                  fname: FileHandle = None):
         """
         Save as ASCII file for use in gmsh.
 
@@ -428,11 +436,11 @@ class Colormap(mpl.colors.ListedColormap):
         def adjust_hue(msh_sat, msh_unsat):
             """If saturation of one of the two colors is much less than the other, hue of the less."""
             if msh_sat[0] >= msh_unsat[0]:
-               return msh_sat[2]
-            else:
-                hSpin = msh_sat[1]/np.sin(msh_sat[1])*np.sqrt(msh_unsat[0]**2.0-msh_sat[0]**2)/msh_sat[0]
-                if msh_sat[2] < - np.pi/3.0: hSpin *= -1.0
-                return msh_sat[2] + hSpin
+                return msh_sat[2]
+
+            hSpin = msh_sat[1]/np.sin(msh_sat[1])*np.sqrt(msh_unsat[0]**2.0-msh_sat[0]**2)/msh_sat[0]
+            if msh_sat[2] < - np.pi/3.0: hSpin *= -1.0
+            return msh_sat[2] + hSpin
 
         lo = np.array(low)
         hi = np.array(high)
@@ -445,9 +453,9 @@ class Colormap(mpl.colors.ListedColormap):
             else:
                 lo = np.array([M_mid,0.0,0.0])
                 frac = 2.0*frac - 1.0
-        if   lo[1] < 0.05 and hi[1] > 0.05:
+        if   lo[1] < 0.05 < hi[1]:
             lo[2] = adjust_hue(hi,lo)
-        elif lo[1] > 0.05 and hi[1] < 0.05:
+        elif hi[1] < 0.05 < lo[1]:
             hi[2] = adjust_hue(lo,hi)
 
         return (1.0 - frac) * lo + frac * hi
@@ -476,7 +484,7 @@ class Colormap(mpl.colors.ListedColormap):
                          'gnuplot', 'gnuplot2', 'CMRmap', 'cubehelix', 'brg',
                          'gist_rainbow', 'rainbow', 'jet', 'nipy_spectral', 'gist_ncar']}
 
-    _predefined_DAMASK = {'orientation':   {'low':  [0.933334,0.878432,0.878431],
+    _predefined_DAMASK = {'orientation':   {'low':  [0.933334,0.878432,0.878431],                   # noqa
                                             'high': [0.250980,0.007843,0.000000]},
                           'strain':        {'low':  [0.941177,0.941177,0.870588],
                                             'high': [0.266667,0.266667,0.000000]},
@@ -621,7 +629,8 @@ class Colormap(mpl.colors.ListedColormap):
 
 
     @staticmethod
-    def _lab2xyz(lab: np.ndarray, ref_white: np.ndarray = _REF_WHITE) -> np.ndarray:
+    def _lab2xyz(lab: np.ndarray,
+                 ref_white: np.ndarray = _REF_WHITE) -> np.ndarray:
         """
         CIE Lab to CIE Xyz.
 
@@ -652,7 +661,8 @@ class Colormap(mpl.colors.ListedColormap):
                         ])*ref_white
 
     @staticmethod
-    def _xyz2lab(xyz: np.ndarray, ref_white: np.ndarray = _REF_WHITE) -> np.ndarray:
+    def _xyz2lab(xyz: np.ndarray,
+                 ref_white: np.ndarray = _REF_WHITE) -> np.ndarray:
         """
         CIE Xyz to CIE Lab.
 
diff --git a/python/damask/_config.py b/python/damask/_config.py
index 2f5904cc6..5f7453b11 100644
--- a/python/damask/_config.py
+++ b/python/damask/_config.py
@@ -2,25 +2,34 @@ import copy
 from io import StringIO
 from collections.abc import Iterable
 import abc
+from pathlib import Path
+from typing import Union, Dict, Any, Type, TypeVar
 
 import numpy as np
 import yaml
 
+from ._typehints import FileHandle
 from . import Rotation
 
+MyType = TypeVar('MyType', bound='Config')
+
 class NiceDumper(yaml.SafeDumper):
     """Make YAML readable for humans."""
 
-    def write_line_break(self, data=None):
+    def write_line_break(self,
+                         data: str = None):
         super().write_line_break(data)
 
         if len(self.indents) == 1:
             super().write_line_break()
 
-    def increase_indent(self, flow=False, indentless=False):
+    def increase_indent(self,
+                        flow: bool = False,
+                        indentless: bool = False):
         return super().increase_indent(flow, False)
 
-    def represent_data(self, data):
+    def represent_data(self,
+                       data: Any):
         """Cast Config objects and its subclasses to dict."""
         if isinstance(data, dict) and type(data) != dict:
             return self.represent_data(dict(data))
@@ -31,14 +40,17 @@ class NiceDumper(yaml.SafeDumper):
         else:
             return super().represent_data(data)
 
-    def ignore_aliases(self, data):
+    def ignore_aliases(self,
+                       data: Any) -> bool:
         """Do not use references to existing objects."""
         return True
 
 class Config(dict):
     """YAML-based configuration."""
 
-    def __init__(self,yml=None,**kwargs):
+    def __init__(self,
+                 yml: Union[str, Dict[str, Any]] = None,
+                 **kwargs):
         """Initialize from YAML, dict, or key=value pairs."""
         if isinstance(yml,str):
             kwargs.update(yaml.safe_load(yml))
@@ -47,7 +59,7 @@ class Config(dict):
 
         super().__init__(**kwargs)
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         """Show as in file."""
         output = StringIO()
         self.save(output)
@@ -55,14 +67,15 @@ class Config(dict):
         return ''.join(output.readlines())
 
 
-    def __copy__(self):
+    def __copy__(self: MyType) -> MyType:
         """Create deep copy."""
         return copy.deepcopy(self)
 
     copy = __copy__
 
 
-    def __or__(self,other):
+    def __or__(self: MyType,
+               other) -> MyType:
         """
         Update configuration with contents of other.
 
@@ -76,18 +89,24 @@ class Config(dict):
         updated : damask.Config
             Updated configuration.
 
+        Note
+        ----
+        This functionality is a backport for Python 3.8
+
         """
         duplicate = self.copy()
         duplicate.update(other)
         return duplicate
 
 
-    def __ior__(self,other):
+    def __ior__(self: MyType,
+                other) -> MyType:
         """Update configuration with contents of other."""
         return self.__or__(other)
 
 
-    def delete(self,keys):
+    def delete(self: MyType,
+               keys: Union[Iterable, str]) -> MyType:
         """
         Remove configuration keys.
 
@@ -109,7 +128,8 @@ class Config(dict):
 
 
     @classmethod
-    def load(cls,fname):
+    def load(cls: Type[MyType],
+             fname: FileHandle) -> MyType:
         """
         Load from yaml file.
 
@@ -124,14 +144,15 @@ class Config(dict):
             Configuration from file.
 
         """
-        try:
+        if isinstance(fname, (str, Path)):
             fhandle = open(fname)
-        except TypeError:
+        else:
             fhandle = fname
         return cls(yaml.safe_load(fhandle))
 
-
-    def save(self,fname,**kwargs):
+    def save(self,
+             fname: FileHandle,
+             **kwargs):
         """
         Save to yaml file.
 
@@ -143,9 +164,9 @@ class Config(dict):
             Keyword arguments parsed to yaml.dump.
 
         """
-        try:
+        if isinstance(fname, (str, Path)):
             fhandle = open(fname,'w',newline='\n')
-        except TypeError:
+        else:
             fhandle = fname
 
         if 'width' not in kwargs:
diff --git a/python/damask/_configmaterial.py b/python/damask/_configmaterial.py
index 1b4d4439c..01d85f6a4 100644
--- a/python/damask/_configmaterial.py
+++ b/python/damask/_configmaterial.py
@@ -1,10 +1,14 @@
 import numpy as np
 import h5py
+from typing import Sequence, Dict, Any, Collection
 
+from ._typehints import FileHandle
 from . import Config
 from . import Rotation
 from . import Orientation
 from . import util
+from . import Table
+
 
 class ConfigMaterial(Config):
     """
@@ -17,7 +21,9 @@ class ConfigMaterial(Config):
 
     """
 
-    def __init__(self,d=None,**kwargs):
+    def __init__(self,
+                 d: Dict[str, Any] = None,
+                 **kwargs):
         """
         New material configuration.
 
@@ -30,14 +36,17 @@ class ConfigMaterial(Config):
             Initial content specified as pairs of key=value.
 
         """
+        default: Collection
         if d is None:
-            for section,default in {'material':[],'homogenization':{},'phase':{}}.items():
+            for section, default in {'material':[],'homogenization':{},'phase':{}}.items():
                 if section not in kwargs: kwargs.update({section:default})
 
         super().__init__(d,**kwargs)
 
 
-    def save(self,fname='material.yaml',**kwargs):
+    def save(self,
+             fname: FileHandle = 'material.yaml',
+             **kwargs):
         """
         Save to yaml file.
 
@@ -53,7 +62,8 @@ class ConfigMaterial(Config):
 
 
     @classmethod
-    def load(cls,fname='material.yaml'):
+    def load(cls,
+             fname: FileHandle = 'material.yaml') -> 'ConfigMaterial':
         """
         Load from yaml file.
 
@@ -72,10 +82,14 @@ class ConfigMaterial(Config):
 
 
     @staticmethod
-    def load_DREAM3D(fname,
-                     grain_data=None,cell_data=None,cell_ensemble_data='CellEnsembleData',
-                     phases='Phases',Euler_angles='EulerAngles',phase_names='PhaseName',
-                     base_group=None):
+    def load_DREAM3D(fname: str,
+                     grain_data: str = None,
+                     cell_data: str = None,
+                     cell_ensemble_data: str = 'CellEnsembleData',
+                     phases: str = 'Phases',
+                     Euler_angles: str = 'EulerAngles',
+                     phase_names: str = 'PhaseName',
+                     base_group: str = None) -> 'ConfigMaterial':
         """
         Load DREAM.3D (HDF5) file.
 
@@ -154,7 +168,8 @@ class ConfigMaterial(Config):
 
 
     @staticmethod
-    def from_table(table,**kwargs):
+    def from_table(table: Table,
+                   **kwargs) -> 'ConfigMaterial':
         """
         Generate from an ASCII table.
 
@@ -207,7 +222,7 @@ class ConfigMaterial(Config):
 
 
     @property
-    def is_complete(self):
+    def is_complete(self) -> bool:
         """
         Check for completeness.
 
@@ -267,12 +282,11 @@ class ConfigMaterial(Config):
             if homogenization - set(self['homogenization']):
                 print(f'Homogenization(s) {homogenization-set(self["homogenization"])} missing')
                 ok = False
-
         return ok
 
 
     @property
-    def is_valid(self):
+    def is_valid(self) -> bool:
         """
         Check for valid content.
 
@@ -316,7 +330,10 @@ class ConfigMaterial(Config):
         return ok
 
 
-    def material_rename_phase(self,mapping,ID=None,constituent=None):
+    def material_rename_phase(self,
+                              mapping: Dict[str, str],
+                              ID: Sequence[int] = None,
+                              constituent: Sequence[int] = None) -> 'ConfigMaterial':
         """
         Change phase name in material.
 
@@ -347,7 +364,9 @@ class ConfigMaterial(Config):
         return dup
 
 
-    def material_rename_homogenization(self,mapping,ID=None):
+    def material_rename_homogenization(self,
+                                       mapping: Dict[str, str],
+                                       ID: Sequence[int] = None) -> 'ConfigMaterial':
         """
         Change homogenization name in material.
 
@@ -374,7 +393,8 @@ class ConfigMaterial(Config):
         return dup
 
 
-    def material_add(self,**kwargs):
+    def material_add(self,
+                     **kwargs: Any) -> 'ConfigMaterial':
         """
         Add material entries.
 
@@ -453,7 +473,7 @@ class ConfigMaterial(Config):
             N = max(N,s[0]) if len(s)>0 else N
             n = max(n,s[1]) if len(s)>1 else n
 
-        mat = [{'constituents':[{} for _ in range(n)]} for _ in range(N)]
+        mat: Sequence[dict] = [{'constituents':[{} for _ in range(n)]} for _ in range(N)]
 
         if 'v' not in kwargs:
             shaped['v'] = np.broadcast_to(1/n,(N,n))
@@ -461,7 +481,7 @@ class ConfigMaterial(Config):
         map_shape = {'O':(N,n,4),'F_i':(N,n,3,3)}
         for k,v in shaped.items():
             target = map_shape.get(k,(N,n))
-            obj = np.broadcast_to(v.reshape(util.shapeshifter(v.shape,target,mode='right')),target)
+            obj = np.broadcast_to(v.reshape(util.shapeshifter(v.shape, target, mode = 'right')), target)
             for i in range(N):
                 if k in ['phase','O','v','F_i']:
                     for j in range(n):
diff --git a/python/damask/_crystal.py b/python/damask/_crystal.py
index 7a21f9245..0b1c00458 100644
--- a/python/damask/_crystal.py
+++ b/python/damask/_crystal.py
@@ -33,9 +33,9 @@ class Crystal():
     def __init__(self,*,
                  family = None,
                  lattice = None,
-                 a = None,b = None,c = None,
-                 alpha = None,beta = None,gamma = None,
-                 degrees = False):
+                 a: float = None, b: float = None, c: float = None,
+                 alpha: float = None, beta: float = None, gamma: float = None,
+                 degrees: bool = False):
         """
         Representation of crystal in terms of crystal family or Bravais lattice.
 
@@ -62,7 +62,7 @@ class Crystal():
             Angles are given in degrees. Defaults to False.
 
         """
-        if family not in [None] + list(lattice_symmetries.values()):
+        if family is not None and family not in list(lattice_symmetries.values()):
             raise KeyError(f'invalid crystal family "{family}"')
         if lattice is not None and family is not None and family != lattice_symmetries[lattice]:
             raise KeyError(f'incompatible family "{family}" for lattice "{lattice}"')
@@ -107,9 +107,6 @@ class Crystal():
             if np.any([np.roll([self.alpha,self.beta,self.gamma],r)[0]
               >= np.sum(np.roll([self.alpha,self.beta,self.gamma],r)[1:]) for r in range(3)]):
                 raise ValueError ('each lattice angle must be less than sum of others')
-        else:
-            self.a = self.b = self.c = None
-            self.alpha = self.beta = self.gamma = None
 
 
     def __repr__(self):
@@ -122,7 +119,8 @@ class Crystal():
                           'α={:.5g}°, β={:.5g}°, γ={:.5g}°'.format(*np.degrees(self.parameters[3:]))])
 
 
-    def __eq__(self,other):
+    def __eq__(self,
+               other: object) -> bool:
         """
         Equal to other.
 
@@ -132,6 +130,8 @@ class Crystal():
             Crystal to check for equality.
 
         """
+        if not isinstance(other, Crystal):
+            return NotImplemented
         return self.lattice == other.lattice and \
                self.parameters == other.parameters and \
                self.family == other.family
@@ -139,8 +139,7 @@ class Crystal():
     @property
     def parameters(self):
         """Return lattice parameters a, b, c, alpha, beta, gamma."""
-        return (self.a,self.b,self.c,self.alpha,self.beta,self.gamma)
-
+        if hasattr(self,'a'): return (self.a,self.b,self.c,self.alpha,self.beta,self.gamma)
 
     @property
     def immutable(self):
@@ -269,7 +268,7 @@ class Crystal():
         https://doi.org/10.1063/1.1661333
 
         """
-        if None in self.parameters:
+        if self.parameters is None:
             raise KeyError('missing crystal lattice parameters')
         return np.array([
                           [1,0,0],
@@ -315,7 +314,9 @@ class Crystal():
                         + _lattice_points.get(self.lattice if self.lattice == 'hP' else \
                                               self.lattice[-1],None),dtype=float)
 
-    def to_lattice(self, *, direction: np.ndarray = None, plane: np.ndarray = None) -> np.ndarray:
+    def to_lattice(self, *,
+                   direction: np.ndarray = None,
+                   plane: np.ndarray = None) -> np.ndarray:
         """
         Calculate lattice vector corresponding to crystal frame direction or plane normal.
 
@@ -339,7 +340,9 @@ class Crystal():
         return np.einsum('il,...l',basis,axis)
 
 
-    def to_frame(self, *, uvw: np.ndarray = None, hkl: np.ndarray = None) -> np.ndarray:
+    def to_frame(self, *,
+                 uvw: np.ndarray = None,
+                 hkl: np.ndarray = None) -> np.ndarray:
         """
         Calculate crystal frame vector along lattice direction [uvw] or plane normal (hkl).
 
@@ -362,7 +365,8 @@ class Crystal():
         return np.einsum('il,...l',basis,axis)
 
 
-    def kinematics(self, mode: str) -> Dict[str, List[np.ndarray]]:
+    def kinematics(self,
+                   mode: str) -> Dict[str, List[np.ndarray]]:
         """
         Return crystal kinematics systems.
 
@@ -621,7 +625,8 @@ class Crystal():
                     'plane':    [m[:,3:6] for m in master]}
 
 
-    def relation_operations(self, model: str) -> Tuple[str, Rotation]:
+    def relation_operations(self,
+                            model: str) -> Tuple[str, Rotation]:
         """
         Crystallographic orientation relationships for phase transformations.
 
diff --git a/python/damask/_grid.py b/python/damask/_grid.py
index 94f7eefd0..8a9a4bbd9 100644
--- a/python/damask/_grid.py
+++ b/python/damask/_grid.py
@@ -4,7 +4,7 @@ import warnings
 import multiprocessing as mp
 from functools import partial
 import typing
-from typing import Union, Optional, TextIO, List, Sequence, Literal
+from typing import Union, Optional, TextIO, List, Sequence
 from pathlib import Path
 
 import numpy as np
@@ -33,7 +33,7 @@ class Grid:
                  material: np.ndarray,
                  size: FloatSequence,
                  origin: FloatSequence = np.zeros(3),
-                 comments: Union[str, Sequence[str]] = []):
+                 comments: Union[str, Sequence[str]] = None):
         """
         New geometry definition for grid solvers.
 
@@ -53,7 +53,7 @@ class Grid:
         self.material = material
         self.size = size                                                                            # type: ignore
         self.origin = origin                                                                        # type: ignore
-        self.comments = comments                                                                    # type: ignore
+        self.comments = [] if comments is None else comments                                        # type: ignore
 
 
     def __repr__(self) -> str:
@@ -77,7 +77,8 @@ class Grid:
     copy = __copy__
 
 
-    def __eq__(self, other: object) -> bool:
+    def __eq__(self,
+               other: object) -> bool:
         """
         Test equality of other.
 
@@ -101,17 +102,18 @@ class Grid:
         return self._material
 
     @material.setter
-    def material(self, material: np.ndarray):
+    def material(self,
+                 material: np.ndarray):
         if len(material.shape) != 3:
             raise ValueError(f'invalid material shape {material.shape}')
-        elif material.dtype not in np.sctypes['float'] and material.dtype not in np.sctypes['int']:
+        if material.dtype not in np.sctypes['float'] and material.dtype not in np.sctypes['int']:
             raise TypeError(f'invalid material data type {material.dtype}')
-        else:
-            self._material = np.copy(material)
 
-            if self.material.dtype in np.sctypes['float'] and \
-               np.all(self.material == self.material.astype(int).astype(float)):
-                self._material = self.material.astype(int)
+        self._material = np.copy(material)
+
+        if self.material.dtype in np.sctypes['float'] and \
+           np.all(self.material == self.material.astype(int).astype(float)):
+            self._material = self.material.astype(int)
 
 
     @property
@@ -120,11 +122,12 @@ class Grid:
         return self._size
 
     @size.setter
-    def size(self, size: FloatSequence):
+    def size(self,
+             size: FloatSequence):
         if len(size) != 3 or any(np.array(size) < 0):
             raise ValueError(f'invalid size {size}')
-        else:
-            self._size = np.array(size)
+
+        self._size = np.array(size)
 
     @property
     def origin(self) -> np.ndarray:
@@ -132,11 +135,12 @@ class Grid:
         return self._origin
 
     @origin.setter
-    def origin(self, origin: FloatSequence):
+    def origin(self,
+               origin: FloatSequence):
         if len(origin) != 3:
             raise ValueError(f'invalid origin {origin}')
-        else:
-            self._origin = np.array(origin)
+
+        self._origin = np.array(origin)
 
     @property
     def comments(self) -> List[str]:
@@ -144,7 +148,8 @@ class Grid:
         return self._comments
 
     @comments.setter
-    def comments(self, comments: Union[str, Sequence[str]]):
+    def comments(self,
+                 comments: Union[str, Sequence[str]]):
         self._comments = [str(c) for c in comments] if isinstance(comments,list) else [str(comments)]
 
 
@@ -229,8 +234,7 @@ class Grid:
         content = f.readlines()
         for i,line in enumerate(content[:header_length]):
             items = line.split('#')[0].lower().strip().split()
-            key = items[0] if items else ''
-            if   key == 'grid':
+            if (key := items[0] if items else '') ==  'grid':
                 cells  = 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']])
@@ -242,8 +246,7 @@ class Grid:
         material = np.empty(int(cells.prod()))                                                      # initialize as flat array
         i = 0
         for line in content[header_length:]:
-            items = line.split('#')[0].split()
-            if len(items) == 3:
+            if len(items := line.split('#')[0].split()) == 3:
                 if items[1].lower() == 'of':
                     material_entry = np.ones(int(items[0]))*float(items[2])
                 elif items[1].lower() == 'to':
@@ -387,7 +390,9 @@ class Grid:
 
 
     @staticmethod
-    def _find_closest_seed(seeds: np.ndarray, weights: np.ndarray, point: np.ndarray) -> np.integer:
+    def _find_closest_seed(seeds: np.ndarray,
+                           weights: np.ndarray,
+                           point: np.ndarray) -> np.integer:
         return np.argmin(np.sum((np.broadcast_to(point,(len(seeds),3))-seeds)**2,axis=1) - weights)
 
     @staticmethod
@@ -624,7 +629,9 @@ class Grid:
                    )
 
 
-    def save(self, fname: Union[str, Path], compress: bool = True):
+    def save(self,
+             fname: Union[str, Path],
+             compress: bool = True):
         """
         Save as VTK image data file.
 
@@ -643,7 +650,8 @@ class Grid:
         v.save(fname,parallel=False,compress=compress)
 
 
-    def save_ASCII(self, fname: Union[str, TextIO]):
+    def save_ASCII(self,
+                   fname: Union[str, TextIO]):
         """
         Save as geom file.
 
@@ -770,15 +778,16 @@ class Grid:
                    )
 
 
-    def mirror(self, directions: Sequence[str], reflect: bool = False) -> 'Grid':
+    def mirror(self,
+               directions: Sequence[str],
+               reflect: bool = False) -> 'Grid':
         """
         Mirror grid along given directions.
 
         Parameters
         ----------
-        directions : (sequence of) str
+        directions : (sequence of) {'x', 'y', 'z'}
             Direction(s) along which the grid is mirrored.
-            Valid entries are 'x', 'y', 'z'.
         reflect : bool, optional
             Reflect (include) outermost layers. Defaults to False.
 
@@ -801,8 +810,7 @@ class Grid:
         # materials: 1
 
         """
-        valid = ['x','y','z']
-        if not set(directions).issubset(valid):
+        if not set(directions).issubset(valid := ['x', 'y', 'z']):
             raise ValueError(f'invalid direction {set(directions).difference(valid)} specified')
 
         limits: Sequence[Optional[int]] = [None,None] if reflect else [-2,0]
@@ -822,15 +830,15 @@ class Grid:
                    )
 
 
-    def flip(self, directions: Union[Literal['x', 'y', 'z'], Sequence[Literal['x', 'y', 'z']]]) -> 'Grid':
+    def flip(self,
+             directions: Sequence[str]) -> 'Grid':
         """
         Flip grid along given directions.
 
         Parameters
         ----------
-        directions : (sequence of) str
+        directions : (sequence of) {'x', 'y', 'z'}
             Direction(s) along which the grid is flipped.
-            Valid entries are 'x', 'y', 'z'.
 
         Returns
         -------
@@ -838,8 +846,7 @@ class Grid:
             Updated grid-based geometry.
 
         """
-        valid = ['x','y','z']
-        if not set(directions).issubset(valid):
+        if not set(directions).issubset(valid := ['x', 'y', 'z']):
             raise ValueError(f'invalid direction {set(directions).difference(valid)} specified')
 
 
@@ -852,7 +859,9 @@ class Grid:
                    )
 
 
-    def scale(self, cells: IntSequence, periodic: bool = True) -> 'Grid':
+    def scale(self,
+              cells: IntSequence,
+              periodic: bool = True) -> 'Grid':
         """
         Scale grid to new cells.
 
@@ -958,7 +967,9 @@ class Grid:
                    )
 
 
-    def rotate(self, R: Rotation, fill: int = None) -> 'Grid':
+    def rotate(self,
+               R: Rotation,
+               fill: int = None) -> 'Grid':
         """
         Rotate grid (pad if required).
 
@@ -1049,7 +1060,9 @@ class Grid:
                    )
 
 
-    def substitute(self, from_material: IntSequence, to_material: IntSequence) -> 'Grid':
+    def substitute(self,
+                   from_material: IntSequence,
+                   to_material: IntSequence) -> 'Grid':
         """
         Substitute material indices.
 
@@ -1150,7 +1163,9 @@ class Grid:
                    )
 
 
-    def get_grain_boundaries(self, periodic: bool = True, directions: Sequence[str] = 'xyz'):
+    def get_grain_boundaries(self,
+                             periodic: bool = True,
+                             directions: Sequence[str] = 'xyz') -> VTK:
         """
         Create VTK unstructured grid containing grain boundaries.
 
@@ -1158,9 +1173,9 @@ class Grid:
         ----------
         periodic : bool, optional
             Assume grid to be periodic. Defaults to True.
-        directions : (sequence of) string, optional
+        directions : (sequence of) {'x', 'y', 'z'}, optional
             Direction(s) along which the boundaries are determined.
-            Valid entries are 'x', 'y', 'z'. Defaults to 'xyz'.
+            Defaults to 'xyz'.
 
         Returns
         -------
@@ -1168,8 +1183,7 @@ class Grid:
             VTK-based geometry of grain boundary network.
 
         """
-        valid = ['x','y','z']
-        if not set(directions).issubset(valid):
+        if not set(directions).issubset(valid := ['x', 'y', 'z']):
             raise ValueError(f'invalid direction {set(directions).difference(valid)} specified')
 
         o = [[0, self.cells[0]+1,           np.prod(self.cells[:2]+1)+self.cells[0]+1, np.prod(self.cells[:2]+1)],
diff --git a/python/damask/_table.py b/python/damask/_table.py
index fed309439..1572c4f76 100644
--- a/python/damask/_table.py
+++ b/python/damask/_table.py
@@ -1,7 +1,7 @@
 import re
 import copy
 from pathlib import Path
-from typing import Union, Optional, Tuple, List
+from typing import Union, Tuple, List
 
 import pandas as pd
 import numpy as np
@@ -12,7 +12,10 @@ from . import util
 class Table:
     """Manipulate multi-dimensional spreadsheet-like data."""
 
-    def __init__(self, data: np.ndarray, shapes: dict, comments: Optional[Union[str, list]] = None):
+    def __init__(self,
+                 data: np.ndarray,
+                 shapes: dict,
+                 comments: Union[str, list] = None):
         """
         New spreadsheet.
 
@@ -41,7 +44,8 @@ class Table:
         return '\n'.join(['# '+c for c in self.comments])+'\n'+data_repr
 
 
-    def __getitem__(self, item: Union[slice, Tuple[slice, ...]]) -> 'Table':
+    def __getitem__(self,
+                    item: Union[slice, Tuple[slice, ...]]) -> 'Table':
         """
         Slice the Table according to item.
 
@@ -100,7 +104,9 @@ class Table:
     copy = __copy__
 
 
-    def _label(self, what: Union[str, List[str]], how: str) -> List[str]:
+    def _label(self,
+               what: Union[str, List[str]],
+               how: str) -> List[str]:
         """
         Expand labels according to data shape.
 
@@ -131,7 +137,8 @@ class Table:
         return labels
 
 
-    def _relabel(self, how: str):
+    def _relabel(self,
+                 how: str):
         """
         Modify labeling of data in-place.
 
@@ -147,7 +154,10 @@ class Table:
         self.data.columns = self._label(self.shapes,how) #type: ignore
 
 
-    def _add_comment(self, label: str, shape: Tuple[int, ...], info: Optional[str]):
+    def _add_comment(self,
+                     label: str,
+                     shape: Tuple[int, ...],
+                     info: str = None):
         if info is not None:
             specific = f'{label}{" "+str(shape) if np.prod(shape,dtype=int) > 1 else ""}: {info}'
             general  = util.execution_stamp('Table')
@@ -309,8 +319,7 @@ class Table:
         data = np.loadtxt(content)
 
         shapes = {'eu':3, 'pos':2, 'IQ':1, 'CI':1, 'ID':1, 'intensity':1, 'fit':1}
-        remainder = data.shape[1]-sum(shapes.values())
-        if remainder > 0:                                                       # 3.8 can do: if (remainder := data.shape[1]-sum(shapes.values())) > 0
+        if (remainder := data.shape[1]-sum(shapes.values())) > 0:
             shapes['unknown'] = remainder
 
         return Table(data,shapes,comments)
@@ -321,7 +330,8 @@ class Table:
         return list(self.shapes)
 
 
-    def get(self, label: str) -> np.ndarray:
+    def get(self,
+            label: str) -> np.ndarray:
         """
         Get column data.
 
@@ -341,7 +351,10 @@ class Table:
         return data.astype(type(data.flatten()[0]))
 
 
-    def set(self, label: str, data: np.ndarray, info: str = None) -> 'Table':
+    def set(self,
+            label: str,
+            data: np.ndarray,
+            info: str = None) -> 'Table':
         """
         Set column data.
 
@@ -362,8 +375,7 @@ class Table:
         """
         dup = self.copy()
         dup._add_comment(label, data.shape[1:], info)
-        m = re.match(r'(.*)\[((\d+,)*(\d+))\]',label)
-        if m:
+        if m := re.match(r'(.*)\[((\d+,)*(\d+))\]',label):
             key = m.group(1)
             idx = np.ravel_multi_index(tuple(map(int,m.group(2).split(","))),
                                        self.shapes[key])
@@ -374,7 +386,10 @@ class Table:
         return dup
 
 
-    def add(self, label: str, data: np.ndarray, info: str = None) -> 'Table':
+    def add(self,
+            label: str,
+            data: np.ndarray,
+            info: str = None) -> 'Table':
         """
         Add column data.
 
@@ -406,7 +421,8 @@ class Table:
         return dup
 
 
-    def delete(self, label: str) -> 'Table':
+    def delete(self,
+               label: str) -> 'Table':
         """
         Delete column data.
 
@@ -427,7 +443,10 @@ class Table:
         return dup
 
 
-    def rename(self, old: Union[str, List[str]], new: Union[str, List[str]], info: str = None) -> 'Table':
+    def rename(self,
+               old: Union[str, List[str]],
+               new: Union[str, List[str]],
+               info: str = None) -> 'Table':
         """
         Rename column data.
 
@@ -453,7 +472,9 @@ class Table:
         return dup
 
 
-    def sort_by(self, labels: Union[str, List[str]], ascending: Union[bool, List[bool]] = True) -> 'Table':
+    def sort_by(self,
+                labels: Union[str, List[str]],
+                ascending: Union[bool, List[bool]] = True) -> 'Table':
         """
         Sort table by values of given labels.
 
@@ -472,8 +493,7 @@ class Table:
         """
         labels_ = [labels] if isinstance(labels,str) else labels.copy()
         for i,l in enumerate(labels_):
-            m = re.match(r'(.*)\[((\d+,)*(\d+))\]',l)
-            if m:
+            if m := re.match(r'(.*)\[((\d+,)*(\d+))\]',l):
                 idx = np.ravel_multi_index(tuple(map(int,m.group(2).split(','))),
                                            self.shapes[m.group(1)])
                 labels_[i] = f'{1+idx}_{m.group(1)}'
@@ -486,7 +506,8 @@ class Table:
         return dup
 
 
-    def append(self, other: 'Table') -> 'Table':
+    def append(self,
+               other: 'Table') -> 'Table':
         """
         Append other table vertically (similar to numpy.vstack).
 
@@ -505,13 +526,14 @@ class Table:
         """
         if self.shapes != other.shapes or not self.data.columns.equals(other.data.columns):
             raise KeyError('Labels or shapes or order do not match')
-        else:
-            dup = self.copy()
-            dup.data = dup.data.append(other.data,ignore_index=True)
-            return dup
+
+        dup = self.copy()
+        dup.data = dup.data.append(other.data,ignore_index=True)
+        return dup
 
 
-    def join(self, other: 'Table') -> 'Table':
+    def join(self,
+             other: 'Table') -> 'Table':
         """
         Append other table horizontally (similar to numpy.hstack).
 
@@ -530,15 +552,16 @@ class Table:
         """
         if set(self.shapes) & set(other.shapes) or self.data.shape[0] != other.data.shape[0]:
             raise KeyError('Duplicated keys or row count mismatch')
-        else:
-            dup = self.copy()
-            dup.data = dup.data.join(other.data)
-            for key in other.shapes:
-                dup.shapes[key] = other.shapes[key]
-            return dup
+
+        dup = self.copy()
+        dup.data = dup.data.join(other.data)
+        for key in other.shapes:
+            dup.shapes[key] = other.shapes[key]
+        return dup
 
 
-    def save(self, fname: FileHandle):
+    def save(self,
+             fname: FileHandle):
         """
         Save as plain text file.
 
diff --git a/python/damask/_vtk.py b/python/damask/_vtk.py
index 4e3f27e0e..3d9e5011c 100644
--- a/python/damask/_vtk.py
+++ b/python/damask/_vtk.py
@@ -22,7 +22,8 @@ class VTK:
     High-level interface to VTK.
     """
 
-    def __init__(self, vtk_data: vtk.vtkDataSet):
+    def __init__(self,
+                 vtk_data: vtk.vtkDataSet):
         """
         New spatial visualization.
 
@@ -38,7 +39,9 @@ class VTK:
 
 
     @staticmethod
-    def from_image_data(cells: IntSequence, size: FloatSequence, origin: FloatSequence = np.zeros(3)) -> 'VTK':
+    def from_image_data(cells: IntSequence,
+                        size: FloatSequence,
+                        origin: FloatSequence = np.zeros(3)) -> 'VTK':
         """
         Create VTK of type vtk.vtkImageData.
 
@@ -68,7 +71,9 @@ class VTK:
 
 
     @staticmethod
-    def from_rectilinear_grid(grid: np.ndarray, size: FloatSequence, origin: FloatSequence = np.zeros(3)) -> 'VTK':
+    def from_rectilinear_grid(grid: np.ndarray,
+                              size: FloatSequence,
+                              origin: FloatSequence = np.zeros(3)) -> 'VTK':
         """
         Create VTK of type vtk.vtkRectilinearGrid.
 
@@ -100,7 +105,9 @@ class VTK:
 
 
     @staticmethod
-    def from_unstructured_grid(nodes: np.ndarray, connectivity: np.ndarray, cell_type: str) -> 'VTK':
+    def from_unstructured_grid(nodes: np.ndarray,
+                               connectivity: np.ndarray,
+                               cell_type: str) -> 'VTK':
         """
         Create VTK of type vtk.vtkUnstructuredGrid.
 
@@ -195,8 +202,7 @@ class VTK:
         """
         if not os.path.isfile(fname):                                                               # vtk has a strange error handling
             raise FileNotFoundError(f'No such file: {fname}')
-        ext = Path(fname).suffix
-        if ext == '.vtk' or dataset_type is not None:
+        if (ext := Path(fname).suffix) == '.vtk' or dataset_type is not None:
             reader = vtk.vtkGenericDataObjectReader()
             reader.SetFileName(str(fname))
             if dataset_type is None:
@@ -238,7 +244,11 @@ class VTK:
     def _write(writer):
         """Wrapper for parallel writing."""
         writer.Write()
-    def save(self, fname: Union[str, Path], parallel: bool = True, compress: bool = True):
+
+    def save(self,
+             fname: Union[str, Path],
+             parallel: bool = True,
+             compress: bool = True):
         """
         Save as VTK file.
 
@@ -284,7 +294,9 @@ class VTK:
 
     # Check https://blog.kitware.com/ghost-and-blanking-visibility-changes/ for missing data
     # Needs support for damask.Table
-    def add(self, data: Union[np.ndarray, np.ma.MaskedArray], label: str = None):
+    def add(self,
+            data: Union[np.ndarray, np.ma.MaskedArray],
+            label: str = None):
         """
         Add data to either cells or points.
 
@@ -331,7 +343,8 @@ class VTK:
             raise TypeError
 
 
-    def get(self, label: str) -> np.ndarray:
+    def get(self,
+            label: str) -> np.ndarray:
         """
         Get either cell or point data.
 
@@ -383,7 +396,8 @@ class VTK:
         return []
 
 
-    def set_comments(self, comments: Union[str, List[str]]):
+    def set_comments(self,
+                     comments: Union[str, List[str]]):
         """
         Set comments.
 
@@ -400,7 +414,8 @@ class VTK:
         self.vtk_data.GetFieldData().AddArray(s)
 
 
-    def add_comments(self, comments: Union[str, List[str]]):
+    def add_comments(self,
+                     comments: Union[str, List[str]]):
         """
         Add comments.
 
@@ -440,7 +455,7 @@ class VTK:
                 width  = tk.winfo_screenwidth()
                 height = tk.winfo_screenheight()
                 tk.destroy()
-            except Exception as e:
+            except Exception:
                 width  = 1024
                 height =  768
 
diff --git a/python/damask/grid_filters.py b/python/damask/grid_filters.py
index d9d658d0b..e2178a4b6 100644
--- a/python/damask/grid_filters.py
+++ b/python/damask/grid_filters.py
@@ -20,7 +20,9 @@ import numpy as _np
 from ._typehints import FloatSequence as _FloatSequence, IntSequence as _IntSequence
 
 
-def _ks(size: _FloatSequence, cells: _IntSequence, first_order: bool = False) -> _np.ndarray:
+def _ks(size: _FloatSequence,
+        cells: _IntSequence,
+        first_order: bool = False) -> _np.ndarray:
     """
     Get wave numbers operator.
 
@@ -47,7 +49,8 @@ def _ks(size: _FloatSequence, cells: _IntSequence, first_order: bool = False) ->
     return _np.stack(_np.meshgrid(k_sk,k_sj,k_si,indexing = 'ij'), axis=-1)
 
 
-def curl(size: _FloatSequence, f: _np.ndarray) -> _np.ndarray:
+def curl(size: _FloatSequence,
+         f: _np.ndarray) -> _np.ndarray:
     u"""
     Calculate curl of a vector or tensor field in Fourier space.
 
@@ -78,7 +81,8 @@ def curl(size: _FloatSequence, f: _np.ndarray) -> _np.ndarray:
     return _np.fft.irfftn(curl_,axes=(0,1,2),s=f.shape[:3])
 
 
-def divergence(size: _FloatSequence, f: _np.ndarray) -> _np.ndarray:
+def divergence(size: _FloatSequence,
+               f: _np.ndarray) -> _np.ndarray:
     u"""
     Calculate divergence of a vector or tensor field in Fourier space.
 
@@ -105,7 +109,8 @@ def divergence(size: _FloatSequence, f: _np.ndarray) -> _np.ndarray:
     return _np.fft.irfftn(div_,axes=(0,1,2),s=f.shape[:3])
 
 
-def gradient(size: _FloatSequence, f: _np.ndarray) -> _np.ndarray:
+def gradient(size: _FloatSequence,
+             f: _np.ndarray) -> _np.ndarray:
     u"""
     Calculate gradient of a scalar or vector field in Fourier space.
 
@@ -163,7 +168,8 @@ def coordinates0_point(cells: _IntSequence,
                      axis = -1)
 
 
-def displacement_fluct_point(size: _FloatSequence, F: _np.ndarray) -> _np.ndarray:
+def displacement_fluct_point(size: _FloatSequence,
+                             F: _np.ndarray) -> _np.ndarray:
     """
     Cell center displacement field from fluctuation part of the deformation gradient field.
 
@@ -195,7 +201,8 @@ def displacement_fluct_point(size: _FloatSequence, F: _np.ndarray) -> _np.ndarra
     return _np.fft.irfftn(displacement,axes=(0,1,2),s=F.shape[:3])
 
 
-def displacement_avg_point(size: _FloatSequence, F: _np.ndarray) -> _np.ndarray:
+def displacement_avg_point(size: _FloatSequence,
+                           F: _np.ndarray) -> _np.ndarray:
     """
     Cell center displacement field from average part of the deformation gradient field.
 
@@ -216,7 +223,8 @@ def displacement_avg_point(size: _FloatSequence, F: _np.ndarray) -> _np.ndarray:
     return _np.einsum('ml,ijkl->ijkm',F_avg - _np.eye(3),coordinates0_point(F.shape[:3],size))
 
 
-def displacement_point(size: _FloatSequence, F: _np.ndarray) -> _np.ndarray:
+def displacement_point(size: _FloatSequence,
+                       F: _np.ndarray) -> _np.ndarray:
     """
     Cell center displacement field from deformation gradient field.
 
@@ -236,7 +244,9 @@ def displacement_point(size: _FloatSequence, F: _np.ndarray) -> _np.ndarray:
     return displacement_avg_point(size,F) + displacement_fluct_point(size,F)
 
 
-def coordinates_point(size: _FloatSequence, F: _np.ndarray, origin: _FloatSequence = _np.zeros(3)) -> _np.ndarray:
+def coordinates_point(size: _FloatSequence,
+                      F: _np.ndarray,
+                      origin: _FloatSequence = _np.zeros(3)) -> _np.ndarray:
     """
     Cell center positions.
 
@@ -335,7 +345,8 @@ def coordinates0_node(cells: _IntSequence,
                      axis = -1)
 
 
-def displacement_fluct_node(size: _FloatSequence, F: _np.ndarray) -> _np.ndarray:
+def displacement_fluct_node(size: _FloatSequence,
+                            F: _np.ndarray) -> _np.ndarray:
     """
     Nodal displacement field from fluctuation part of the deformation gradient field.
 
@@ -355,7 +366,8 @@ def displacement_fluct_node(size: _FloatSequence, F: _np.ndarray) -> _np.ndarray
     return point_to_node(displacement_fluct_point(size,F))
 
 
-def displacement_avg_node(size: _FloatSequence, F: _np.ndarray) -> _np.ndarray:
+def displacement_avg_node(size: _FloatSequence,
+                          F: _np.ndarray) -> _np.ndarray:
     """
     Nodal displacement field from average part of the deformation gradient field.
 
@@ -376,7 +388,8 @@ def displacement_avg_node(size: _FloatSequence, F: _np.ndarray) -> _np.ndarray:
     return _np.einsum('ml,ijkl->ijkm',F_avg - _np.eye(3),coordinates0_node(F.shape[:3],size))
 
 
-def displacement_node(size: _FloatSequence, F: _np.ndarray) -> _np.ndarray:
+def displacement_node(size: _FloatSequence,
+                      F: _np.ndarray) -> _np.ndarray:
     """
     Nodal displacement field from deformation gradient field.
 
@@ -396,7 +409,9 @@ def displacement_node(size: _FloatSequence, F: _np.ndarray) -> _np.ndarray:
     return displacement_avg_node(size,F) + displacement_fluct_node(size,F)
 
 
-def coordinates_node(size: _FloatSequence, F: _np.ndarray, origin: _FloatSequence = _np.zeros(3)) -> _np.ndarray:
+def coordinates_node(size: _FloatSequence,
+                     F: _np.ndarray,
+                     origin: _FloatSequence = _np.zeros(3)) -> _np.ndarray:
     """
     Nodal positions.
 
@@ -526,7 +541,9 @@ def coordinates0_valid(coordinates0: _np.ndarray) -> bool:
         return False
 
 
-def regrid(size: _FloatSequence, F: _np.ndarray, cells: _IntSequence) -> _np.ndarray:
+def regrid(size: _FloatSequence,
+           F: _np.ndarray,
+           cells: _IntSequence) -> _np.ndarray:
     """
     Return mapping from coordinates in deformed configuration to a regular grid.
 
diff --git a/python/damask/mechanics.py b/python/damask/mechanics.py
index 7c1af6c5f..65ec1ef3b 100644
--- a/python/damask/mechanics.py
+++ b/python/damask/mechanics.py
@@ -122,7 +122,9 @@ def rotation(T: _np.ndarray) -> _rotation.Rotation:
     return _rotation.Rotation.from_matrix(_polar_decomposition(T,'R')[0])
 
 
-def strain(F: _np.ndarray, t: str, m: float) -> _np.ndarray:
+def strain(F: _np.ndarray,
+           t: str,
+           m: float) -> _np.ndarray:
     """
     Calculate strain tensor (Seth–Hill family).
 
@@ -162,7 +164,8 @@ def strain(F: _np.ndarray, t: str, m: float) -> _np.ndarray:
     return eps
 
 
-def stress_Cauchy(P: _np.ndarray, F: _np.ndarray) -> _np.ndarray:
+def stress_Cauchy(P: _np.ndarray,
+                  F: _np.ndarray) -> _np.ndarray:
     """
     Calculate the Cauchy stress (true stress).
 
@@ -184,7 +187,8 @@ def stress_Cauchy(P: _np.ndarray, F: _np.ndarray) -> _np.ndarray:
     return _tensor.symmetric(_np.einsum('...,...ij,...kj',1.0/_np.linalg.det(F),P,F))
 
 
-def stress_second_Piola_Kirchhoff(P: _np.ndarray, F: _np.ndarray) -> _np.ndarray:
+def stress_second_Piola_Kirchhoff(P: _np.ndarray,
+                                  F: _np.ndarray) -> _np.ndarray:
     """
     Calculate the second Piola-Kirchhoff stress.
 
@@ -243,7 +247,8 @@ def stretch_right(T: _np.ndarray) -> _np.ndarray:
     return _polar_decomposition(T,'U')[0]
 
 
-def _polar_decomposition(T: _np.ndarray, requested: _Sequence[str]) -> tuple:
+def _polar_decomposition(T: _np.ndarray,
+                         requested: _Sequence[str]) -> tuple:
     """
     Perform singular value decomposition.
 
@@ -251,7 +256,7 @@ def _polar_decomposition(T: _np.ndarray, requested: _Sequence[str]) -> tuple:
     ----------
     T : numpy.ndarray, shape (...,3,3)
         Tensor of which the singular values are computed.
-    requested : iterable of str
+    requested : sequence of {'R', 'U', 'V'}
         Requested outputs: ‘R’ for the rotation tensor,
         ‘V’ for left stretch tensor and ‘U’ for right stretch tensor.
 
@@ -273,7 +278,8 @@ def _polar_decomposition(T: _np.ndarray, requested: _Sequence[str]) -> tuple:
     return tuple(output)
 
 
-def _equivalent_Mises(T_sym: _np.ndarray, s: float) -> _np.ndarray:
+def _equivalent_Mises(T_sym: _np.ndarray,
+                      s: float) -> _np.ndarray:
     """
     Base equation for Mises equivalent of a stress or strain tensor.
 
diff --git a/python/damask/seeds.py b/python/damask/seeds.py
index e6d1f9613..47e34d871 100644
--- a/python/damask/seeds.py
+++ b/python/damask/seeds.py
@@ -10,7 +10,9 @@ from . import util as _util
 from . import grid_filters as _grid_filters
 
 
-def from_random(size: _FloatSequence, N_seeds: int, cells: _IntSequence = None,
+def from_random(size: _FloatSequence,
+                N_seeds: int,
+                cells: _IntSequence = None,
                 rng_seed=None) -> _np.ndarray:
     """
     Place seeds randomly in space.
@@ -46,8 +48,12 @@ def from_random(size: _FloatSequence, N_seeds: int, cells: _IntSequence = None,
     return coords
 
 
-def from_Poisson_disc(size: _FloatSequence, N_seeds: int, N_candidates: int, distance: float,
-                      periodic: bool = True, rng_seed=None) -> _np.ndarray:
+def from_Poisson_disc(size: _FloatSequence,
+                      N_seeds: int,
+                      N_candidates: int,
+                      distance: float,
+                      periodic: bool = True,
+                      rng_seed=None) -> _np.ndarray:
     """
     Place seeds according to a Poisson disc distribution.
 
@@ -86,10 +92,9 @@ def from_Poisson_disc(size: _FloatSequence, N_seeds: int, N_candidates: int, dis
         tree = _spatial.cKDTree(coords[:s],boxsize=size) if periodic else \
                _spatial.cKDTree(coords[:s])
         distances = tree.query(candidates)[0]
-        best = distances.argmax()
-        if distances[best] > distance:                                                              # require minimum separation
+        if distances.max() > distance:                                                              # require minimum separation
             i = 0
-            coords[s] = candidates[best]                                                            # maximum separation to existing point cloud
+            coords[s] = candidates[distances.argmax()]                                              # maximum separation to existing point cloud
             s += 1
             progress.update(s)
 
@@ -99,8 +104,11 @@ def from_Poisson_disc(size: _FloatSequence, N_seeds: int, N_candidates: int, dis
     return coords
 
 
-def from_grid(grid, selection: _IntSequence = None, invert_selection: bool = False,
-              average: bool = False, periodic: bool = True) -> _Tuple[_np.ndarray, _np.ndarray]:
+def from_grid(grid,
+              selection: _IntSequence = None,
+              invert_selection: bool = False,
+              average: bool = False,
+              periodic: bool = True) -> _Tuple[_np.ndarray, _np.ndarray]:
     """
     Create seeds from grid description.
 
diff --git a/python/damask/tensor.py b/python/damask/tensor.py
index 4f6cb36ea..63eb15b99 100644
--- a/python/damask/tensor.py
+++ b/python/damask/tensor.py
@@ -45,7 +45,8 @@ def eigenvalues(T_sym: _np.ndarray) -> _np.ndarray:
     return _np.linalg.eigvalsh(symmetric(T_sym))
 
 
-def eigenvectors(T_sym: _np.ndarray, RHS: bool = False) -> _np.ndarray:
+def eigenvectors(T_sym: _np.ndarray,
+                 RHS: bool = False) -> _np.ndarray:
     """
     Eigenvectors of a symmetric tensor.
 
@@ -63,14 +64,14 @@ def eigenvectors(T_sym: _np.ndarray, RHS: bool = False) -> _np.ndarray:
         associated eigenvalues.
 
     """
-    (u,v) = _np.linalg.eigh(symmetric(T_sym))
+    _,v = _np.linalg.eigh(symmetric(T_sym))
 
-    if RHS:
-        v[_np.linalg.det(v) < 0.0,:,2] *= -1.0
+    if RHS: v[_np.linalg.det(v) < 0.0,:,2] *= -1.0
     return v
 
 
-def spherical(T: _np.ndarray, tensor: bool = True) -> _np.ndarray:
+def spherical(T: _np.ndarray,
+              tensor: bool = True) -> _np.ndarray:
     """
     Calculate spherical part of a tensor.
 
diff --git a/python/damask/util.py b/python/damask/util.py
index 2872762b9..b4c287884 100644
--- a/python/damask/util.py
+++ b/python/damask/util.py
@@ -7,16 +7,16 @@ import subprocess
 import shlex
 import re
 import fractions
-import collections.abc as abc
+from collections import abc
 from functools import reduce
-from typing import Union, Tuple, Iterable, Callable, Dict, List, Any, Literal, Optional
+from typing import Union, Tuple, Iterable, Callable, Dict, List, Any, Literal, SupportsIndex, Sequence
 from pathlib import Path
 
 import numpy as np
 import h5py
 
 from . import version
-from ._typehints import FloatSequence
+from ._typehints import IntSequence, FloatSequence
 
 # limit visibility
 __all__=[
@@ -54,7 +54,8 @@ _colors = {
 ####################################################################################################
 # Functions
 ####################################################################################################
-def srepr(msg, glue: str = '\n') -> str:
+def srepr(msg,
+          glue: str = '\n') -> str:
     r"""
     Join items with glue string.
 
@@ -76,7 +77,7 @@ def srepr(msg, glue: str = '\n') -> str:
             hasattr(msg, '__iter__'))):
         return glue.join(str(x) for x in msg)
     else:
-       return msg if isinstance(msg,str) else repr(msg)
+        return msg if isinstance(msg,str) else repr(msg)
 
 
 def emph(msg) -> str:
@@ -148,7 +149,10 @@ def strikeout(msg) -> str:
     return _colors['crossout']+srepr(msg)+_colors['end_color']
 
 
-def run(cmd: str, wd: str = './', env: Dict[str, str] = None, timeout: int = None) -> Tuple[str, str]:
+def run(cmd: str,
+        wd: str = './',
+        env: Dict[str, str] = None,
+        timeout: int = None) -> Tuple[str, str]:
     """
     Run a command.
 
@@ -226,15 +230,15 @@ def show_progress(iterable: Iterable,
 
     """
     if isinstance(iterable,abc.Sequence):
-       if N_iter is None:
-          N = len(iterable)
-       else:
-          raise ValueError('N_iter given for sequence')
+        if N_iter is None:
+            N = len(iterable)
+        else:
+            raise ValueError('N_iter given for sequence')
     else:
-       if N_iter is None:
-          raise ValueError('N_iter not given')
-       else:
-          N = N_iter
+        if N_iter is None:
+            raise ValueError('N_iter not given')
+
+        N = N_iter
 
     if N <= 1:
         for item in iterable:
@@ -301,16 +305,20 @@ def project_equal_angle(vector: np.ndarray,
     normalize : bool
         Ensure unit length of input vector. Defaults to True.
     keepdims : bool
-        Maintain three-dimensional output coordinates. Defaults to False.
-        Two-dimensional output uses right-handed frame spanned by
-        the next and next-next axis relative to the projection direction,
-        e.g. x-y when projecting along z and z-x when projecting along y.
+        Maintain three-dimensional output coordinates.
+        Defaults to False.
 
     Returns
     -------
     coordinates : numpy.ndarray, shape (...,2 | 3)
         Projected coordinates.
 
+    Notes
+    -----
+    Two-dimensional output uses right-handed frame spanned by
+    the next and next-next axis relative to the projection direction,
+    e.g. x-y when projecting along z and z-x when projecting along y.
+
     Examples
     --------
     >>> import damask
@@ -345,16 +353,21 @@ def project_equal_area(vector: np.ndarray,
     normalize : bool
         Ensure unit length of input vector. Defaults to True.
     keepdims : bool
-        Maintain three-dimensional output coordinates. Defaults to False.
-        Two-dimensional output uses right-handed frame spanned by
-        the next and next-next axis relative to the projection direction,
-        e.g. x-y when projecting along z and z-x when projecting along y.
+        Maintain three-dimensional output coordinates.
+        Defaults to False.
 
     Returns
     -------
     coordinates : numpy.ndarray, shape (...,2 | 3)
         Projected coordinates.
 
+    Notes
+    -----
+    Two-dimensional output uses right-handed frame spanned by
+    the next and next-next axis relative to the projection direction,
+    e.g. x-y when projecting along z and z-x when projecting along y.
+
+
     Examples
     --------
     >>> import damask
@@ -373,14 +386,17 @@ def project_equal_area(vector: np.ndarray,
     return np.roll(np.block([v[...,:2]/np.sqrt(1.0+np.abs(v[...,2:3])),np.zeros_like(v[...,2:3])]),
                    -shift if keepdims else 0,axis=-1)[...,:3 if keepdims else 2]
 
-def execution_stamp(class_name: str, function_name: str = None) -> str:
+def execution_stamp(class_name: str,
+                    function_name: str = None) -> str:
     """Timestamp the execution of a (function within a) class."""
     now = datetime.datetime.now().astimezone().strftime('%Y-%m-%d %H:%M:%S%z')
     _function_name = '' if function_name is None else f'.{function_name}'
     return f'damask.{class_name}{_function_name} v{version} ({now})'
 
 
-def hybrid_IA(dist: np.ndarray, N: int, rng_seed = None) -> np.ndarray:
+def hybrid_IA(dist: np.ndarray,
+              N: int,
+              rng_seed: Union[int, IntSequence] = None) -> np.ndarray:
     """
     Hybrid integer approximation.
 
@@ -411,7 +427,7 @@ def hybrid_IA(dist: np.ndarray, N: int, rng_seed = None) -> np.ndarray:
 def shapeshifter(fro: Tuple[int, ...],
                  to: Tuple[int, ...],
                  mode: Literal['left','right'] = 'left',
-                 keep_ones: bool = False) -> Tuple[Optional[int], ...]:
+                 keep_ones: bool = False) -> Sequence[SupportsIndex]:
     """
     Return dimensions that reshape 'fro' to become broadcastable to 'to'.
 
@@ -447,7 +463,7 @@ def shapeshifter(fro: Tuple[int, ...],
 
 
     """
-    if not len(fro) and not len(to): return ()
+    if len(fro) == 0 and len(to) == 0: return ()
 
     beg = dict(left ='(^.*\\b)',
                right='(^.*?\\b)')
@@ -455,8 +471,8 @@ def shapeshifter(fro: Tuple[int, ...],
                right='(.*?\\b)')
     end = dict(left ='(.*?$)',
                right='(.*$)')
-    fro = (1,) if not len(fro) else fro
-    to  = (1,) if not len(to)  else to
+    fro = (1,) if len(fro) == 0 else fro
+    to  = (1,) if len(to) == 0 else to
     try:
         match = re.match(beg[mode]
                       +f',{sep[mode]}'.join(map(lambda x: f'{x}'
@@ -467,13 +483,14 @@ def shapeshifter(fro: Tuple[int, ...],
         grp = match.groups()
     except AssertionError:
         raise ValueError(f'Shapes can not be shifted {fro} --> {to}')
-    fill: Tuple[Optional[int], ...] = ()
+    fill: Any = ()
     for g,d in zip(grp,fro+(None,)):
         fill += (1,)*g.count(',')+(d,)
     return fill[:-1]
 
 
-def shapeblender(a: Tuple[int, ...], b: Tuple[int, ...]) -> Tuple[int, ...]:
+def shapeblender(a: Tuple[int, ...],
+                 b: Tuple[int, ...]) -> Sequence[SupportsIndex]:
     """
     Return a shape that overlaps the rightmost entries of 'a' with the leftmost of 'b'.
 
@@ -517,7 +534,8 @@ def extend_docstring(extra_docstring: str) -> Callable:
     return _decorator
 
 
-def extended_docstring(f: Callable, extra_docstring: str) -> Callable:
+def extended_docstring(f: Callable,
+                       extra_docstring: str) -> Callable:
     """
     Decorator: Combine another function's docstring with a given docstring.
 
@@ -593,7 +611,9 @@ def DREAM3D_cell_data_group(fname: Union[str, Path]) -> str:
     return cell_data_group
 
 
-def Bravais_to_Miller(*, uvtw: np.ndarray = None, hkil: np.ndarray = None) -> np.ndarray:
+def Bravais_to_Miller(*,
+                      uvtw: np.ndarray = None,
+                      hkil: np.ndarray = None) -> np.ndarray:
     """
     Transform 4 Miller–Bravais indices to 3 Miller indices of crystal direction [uvw] or plane normal (hkl).
 
@@ -620,7 +640,9 @@ def Bravais_to_Miller(*, uvtw: np.ndarray = None, hkil: np.ndarray = None) -> np
     return np.einsum('il,...l',basis,axis)
 
 
-def Miller_to_Bravais(*, uvw: np.ndarray = None, hkl: np.ndarray = None) -> np.ndarray:
+def Miller_to_Bravais(*,
+                      uvw: np.ndarray = None,
+                      hkl: np.ndarray = None) -> np.ndarray:
     """
     Transform 3 Miller indices to 4 Miller–Bravais indices of crystal direction [uvtw] or plane normal (hkil).
 
@@ -710,7 +732,10 @@ class ProgressBar:
     Works for 0-based loops, ETA is estimated by linear extrapolation.
     """
 
-    def __init__(self, total: int, prefix: str, bar_length: int):
+    def __init__(self,
+                 total: int,
+                 prefix: str,
+                 bar_length: int):
         """
         Set current time as basis for ETA estimation.
 
@@ -733,12 +758,12 @@ class ProgressBar:
         sys.stderr.write(f"{self.prefix} {'░'*self.bar_length}   0% ETA n/a")
         sys.stderr.flush()
 
-    def update(self, iteration: int) -> None:
+    def update(self,
+               iteration: int) -> None:
 
         fraction = (iteration+1) / self.total
-        filled_length = int(self.bar_length * fraction)
 
-        if filled_length > int(self.bar_length * self.fraction_last) or \
+        if filled_length := int(self.bar_length * fraction) > int(self.bar_length * self.fraction_last) or \
             datetime.datetime.now() - self.time_last_update > datetime.timedelta(seconds=10):
             self.time_last_update = datetime.datetime.now()
             bar = '█' * filled_length + '░' * (self.bar_length - filled_length)
diff --git a/python/mypy.ini b/python/mypy.ini
index 01001daa6..5ef04daee 100644
--- a/python/mypy.ini
+++ b/python/mypy.ini
@@ -1,3 +1,5 @@
+[mypy]
+warn_redundant_casts = True
 [mypy-scipy.*]
 ignore_missing_imports = True
 [mypy-h5py.*]
diff --git a/src/CPFEM.f90 b/src/CPFEM.f90
index 8ee26ffe7..0f7590782 100644
--- a/src/CPFEM.f90
+++ b/src/CPFEM.f90
@@ -14,6 +14,7 @@ module CPFEM
   use config
   use math
   use rotations
+  use polynomials
   use lattice
   use material
   use phase
@@ -83,6 +84,7 @@ subroutine CPFEM_initAll
   call config_init
   call math_init
   call rotations_init
+  call polynomials_init
   call lattice_init
   call discretization_marc_init
   call material_init(.false.)
diff --git a/src/CPFEM2.f90 b/src/CPFEM2.f90
index 647befd30..ed8fb611b 100644
--- a/src/CPFEM2.f90
+++ b/src/CPFEM2.f90
@@ -16,6 +16,7 @@ module CPFEM2
   use config
   use math
   use rotations
+  use polynomials
   use lattice
   use material
   use phase
@@ -57,6 +58,7 @@ subroutine CPFEM_initAll
   call config_init
   call math_init
   call rotations_init
+  call polynomials_init
   call lattice_init
 #if   defined(MESH)
   call discretization_mesh_init(restart=interface_restartInc>0)
diff --git a/src/YAML_parse.f90 b/src/YAML_parse.f90
index 9ebde963b..8a3264cff 100644
--- a/src/YAML_parse.f90
+++ b/src/YAML_parse.f90
@@ -191,8 +191,10 @@ logical function isScalar(line)
 
   character(len=*), intent(in) :: line
 
-  isScalar = (.not.isKeyValue(line) .and. .not.isKey(line) .and. .not.isListItem(line) &
-                                                            .and. .not.isFlow(line))
+  isScalar = (.not. isKeyValue(line) .and. &
+              .not. isKey(line) .and. &
+              .not. isListItem(line) .and. &
+              .not. isFlow(line))
 
 end function isScalar
 
diff --git a/src/commercialFEM_fileList.f90 b/src/commercialFEM_fileList.f90
index e67149dea..8dbbea706 100644
--- a/src/commercialFEM_fileList.f90
+++ b/src/commercialFEM_fileList.f90
@@ -14,6 +14,7 @@
 #include "LAPACK_interface.f90"
 #include "math.f90"
 #include "rotations.f90"
+#include "polynomials.f90"
 #include "lattice.f90"
 #include "element.f90"
 #include "geometry_plastic_nonlocal.f90"
diff --git a/src/material.f90 b/src/material.f90
index 1e3a4b4ec..31eeef5e1 100644
--- a/src/material.f90
+++ b/src/material.f90
@@ -66,7 +66,7 @@ subroutine material_init(restart)
   print'(/,1x,a)', '<<<+-  material init  -+>>>'; flush(IO_STDOUT)
 
 
-  call parse
+  call parse()
   print'(/,1x,a)', 'parsed material.yaml'
 
 
diff --git a/src/phase.f90 b/src/phase.f90
index 6035b4491..df7557a0b 100644
--- a/src/phase.f90
+++ b/src/phase.f90
@@ -8,6 +8,7 @@ module phase
   use constants
   use math
   use rotations
+  use polynomials
   use IO
   use config
   use material
diff --git a/src/phase_mechanical_elastic.f90 b/src/phase_mechanical_elastic.f90
index 8972367d5..c57849b1f 100644
--- a/src/phase_mechanical_elastic.f90
+++ b/src/phase_mechanical_elastic.f90
@@ -1,15 +1,13 @@
 submodule(phase:mechanical) elastic
 
   type :: tParameters
-    real(pReal),dimension(3) :: &
-      C_11 = 0.0_pReal, &
-      C_12 = 0.0_pReal, &
-      C_13 = 0.0_pReal, &
-      C_33 = 0.0_pReal, &
-      C_44 = 0.0_pReal, &
-      C_66 = 0.0_pReal
-    real(pReal) :: &
-      T_ref
+    type(tPolynomial) :: &
+      C_11, &
+      C_12, &
+      C_13, &
+      C_33, &
+      C_44, &
+      C_66
   end type tParameters
 
   type(tParameters), allocatable, dimension(:) :: param
@@ -47,35 +45,17 @@ module subroutine elastic_init(phases)
 
     associate(prm => param(ph))
 
-      prm%T_ref = elastic%get_asFloat('T_ref', defaultVal=T_ROOM)
-
-      prm%C_11(1) = elastic%get_asFloat('C_11')
-      prm%C_11(2) = elastic%get_asFloat('C_11,T',  defaultVal=0.0_pReal)
-      prm%C_11(3) = elastic%get_asFloat('C_11,T^2',defaultVal=0.0_pReal)
- 
-      prm%C_12(1) = elastic%get_asFloat('C_12')
-      prm%C_12(2) = elastic%get_asFloat('C_12,T',  defaultVal=0.0_pReal)
-      prm%C_12(3) = elastic%get_asFloat('C_12,T^2',defaultVal=0.0_pReal)
- 
-      prm%C_44(1) = elastic%get_asFloat('C_44')
-      prm%C_44(2) = elastic%get_asFloat('C_44,T',  defaultVal=0.0_pReal)
-      prm%C_44(3) = elastic%get_asFloat('C_44,T^2',defaultVal=0.0_pReal)
+      prm%C_11 = polynomial(elastic%asDict(),'C_11','T')
+      prm%C_12 = polynomial(elastic%asDict(),'C_12','T')
+      prm%C_44 = polynomial(elastic%asDict(),'C_44','T')
  
       if (any(phase_lattice(ph) == ['hP','tI'])) then
-        prm%C_13(1) = elastic%get_asFloat('C_13')
-        prm%C_13(2) = elastic%get_asFloat('C_13,T',  defaultVal=0.0_pReal)
-        prm%C_13(3) = elastic%get_asFloat('C_13,T^2',defaultVal=0.0_pReal)
- 
-        prm%C_33(1) = elastic%get_asFloat('C_33')
-        prm%C_33(2) = elastic%get_asFloat('C_33,T',  defaultVal=0.0_pReal)
-        prm%C_33(3) = elastic%get_asFloat('C_33,T^2',defaultVal=0.0_pReal)
+        prm%C_13 = polynomial(elastic%asDict(),'C_13','T')
+        prm%C_33 = polynomial(elastic%asDict(),'C_33','T')
       end if
 
-      if (phase_lattice(ph) == 'tI') then
-        prm%C_66(1) = elastic%get_asFloat('C_66')
-        prm%C_66(2) = elastic%get_asFloat('C_66,T',  defaultVal=0.0_pReal)
-        prm%C_66(3) = elastic%get_asFloat('C_66,T^2',defaultVal=0.0_pReal)
-      end if
+      if (phase_lattice(ph) == 'tI') &
+        prm%C_66 = polynomial(elastic%asDict(),'C_66','T')
 
     end associate
   end do
@@ -97,38 +77,20 @@ pure module function elastic_C66(ph,en) result(C66)
 
 
   associate(prm => param(ph))
+    
     C66 = 0.0_pReal
     T = thermal_T(ph,en)
 
-    C66(1,1) = prm%C_11(1) &
-             + prm%C_11(2)*(T - prm%T_ref) &
-             + prm%C_11(3)*(T - prm%T_ref)**2
-
-    C66(1,2) = prm%C_12(1) &
-             + prm%C_12(2)*(T - prm%T_ref) &
-             + prm%C_12(3)*(T - prm%T_ref)**2
-
-    C66(4,4) = prm%C_44(1) &
-             + prm%C_44(2)*(T - prm%T_ref) &
-             + prm%C_44(3)*(T - prm%T_ref)**2
-
+    C66(1,1) = prm%C_11%at(T)
+    C66(1,2) = prm%C_12%at(T)
+    C66(4,4) = prm%C_44%at(T)
 
     if (any(phase_lattice(ph) == ['hP','tI'])) then
-      C66(1,3) = prm%C_13(1) &
-               + prm%C_13(2)*(T - prm%T_ref) &
-               + prm%C_13(3)*(T - prm%T_ref)**2
-
-      C66(3,3) = prm%C_33(1) &
-               + prm%C_33(2)*(T - prm%T_ref) &
-               + prm%C_33(3)*(T - prm%T_ref)**2
-
+      C66(1,3) = prm%C_13%at(T)
+      C66(3,3) = prm%C_33%at(T)
     end if
 
-    if (phase_lattice(ph) == 'tI') then
-      C66(6,6) = prm%C_66(1) &
-               + prm%C_66(2)*(T - prm%T_ref) &
-               + prm%C_66(3)*(T - prm%T_ref)**2
-    end if
+    if (phase_lattice(ph) == 'tI') C66(6,6) = prm%C_66%at(T)
 
     C66 = lattice_symmetrize_C66(C66,phase_lattice(ph))
 
diff --git a/src/polynomials.f90 b/src/polynomials.f90
new file mode 100644
index 000000000..49a46e2e4
--- /dev/null
+++ b/src/polynomials.f90
@@ -0,0 +1,179 @@
+!--------------------------------------------------------------------------------------------------
+!> @author Martin Diehl, KU Leuven
+!> @brief Polynomial representation for variable data
+!--------------------------------------------------------------------------------------------------
+module polynomials
+  use prec
+  use IO
+  use YAML_parse
+  use YAML_types
+
+  implicit none
+  private
+
+  type, public :: tPolynomial
+    real(pReal), dimension(:), allocatable :: coef
+    real(pReal) :: x_ref
+    contains
+    procedure, public :: at => eval
+    procedure, public :: der1_at => eval_der1
+  end type tPolynomial
+
+  interface polynomial
+    module procedure polynomial_from_dict
+    module procedure polynomial_from_coef
+  end interface polynomial
+
+  public :: &
+    polynomial, &
+    polynomials_init
+
+contains
+
+
+!--------------------------------------------------------------------------------------------------
+!> @brief Run self-test.
+!--------------------------------------------------------------------------------------------------
+subroutine polynomials_init()
+
+  print'(/,1x,a)', '<<<+-  polynomials init  -+>>>'; flush(IO_STDOUT)
+
+  call selfTest()
+
+end subroutine polynomials_init
+
+
+!--------------------------------------------------------------------------------------------------
+!> @brief Initialize a Polynomial from Coefficients.
+!--------------------------------------------------------------------------------------------------
+function polynomial_from_coef(coef,x_ref) result(p)
+
+  real(pReal), dimension(:), intent(in) :: coef
+  real(pReal), intent(in) :: x_ref
+  type(tPolynomial) :: p
+
+
+  allocate(p%coef(0:size(coef)-1),source=coef)                                                      ! should be zero based
+  p%x_ref = x_ref
+
+end function polynomial_from_coef
+
+
+!--------------------------------------------------------------------------------------------------
+!> @brief Initialize a Polynomial from a Dictionary with Coefficients.
+!--------------------------------------------------------------------------------------------------
+function polynomial_from_dict(dict,y,x) result(p)
+
+  type(tDict), intent(in) :: dict
+  character(len=*), intent(in) :: y, x
+  type(tPolynomial) :: p
+
+  real(pReal), dimension(:), allocatable :: coef
+  real(pReal) :: x_ref
+
+
+  allocate(coef(1),source=dict%get_asFloat(y))
+
+  if (dict%contains(y//','//x)) then
+    x_ref = dict%get_asFloat(x//'_ref')
+    coef = [coef,dict%get_asFloat(y//','//x)]
+    if (dict%contains(y//','//x//'^2')) then
+      coef = [coef,dict%get_asFloat(y//','//x//'^2')]
+    end if
+  else
+    x_ref = huge(0.0_pReal)                                                                         ! Simplify debugging
+  end if
+
+  p = Polynomial(coef,x_ref)
+
+end function polynomial_from_dict
+
+
+!--------------------------------------------------------------------------------------------------
+!> @brief Evaluate a Polynomial.
+!--------------------------------------------------------------------------------------------------
+pure function eval(self,x) result(y)
+
+  class(tPolynomial), intent(in) :: self
+  real(pReal), intent(in) :: x
+  real(pReal) :: y
+
+  integer :: i
+
+
+  y = self%coef(0)
+  do i = 1, ubound(self%coef,1)
+    y = y + self%coef(i) * (x-self%x_ref)**i
+  enddo
+
+end function eval
+
+
+!--------------------------------------------------------------------------------------------------
+!> @brief Evaluate a first derivative of Polynomial.
+!--------------------------------------------------------------------------------------------------
+pure function eval_der1(self,x) result(y)
+
+  class(tPolynomial), intent(in) :: self
+  real(pReal), intent(in) :: x
+  real(pReal) :: y
+
+  integer :: i
+
+
+  y = 0.0_pReal
+  do i = 1, ubound(self%coef,1)
+    y = y + real(i,pReal)*self%coef(i) * (x-self%x_ref)**(i-1)
+  enddo
+
+end function eval_der1
+
+
+!--------------------------------------------------------------------------------------------------
+!> @brief Check correctness of polynomical functionality.
+!--------------------------------------------------------------------------------------------------
+subroutine selfTest
+
+  type(tPolynomial) :: p1, p2
+  real(pReal), dimension(3) :: coef
+  real(pReal) :: x_ref, x
+  class(tNode), pointer :: dict
+  character(len=pStringLen), dimension(3) :: coef_s
+  character(len=pStringLen) :: x_ref_s, x_s, YAML_s
+
+  call random_number(coef)
+  call random_number(x_ref)
+  call random_number(x)
+
+  coef = coef*10_pReal -0.5_pReal
+  x_ref = x_ref*10_pReal -0.5_pReal
+  x = x*10_pReal -0.5_pReal
+
+  p1 = polynomial(coef,x_ref)
+  if (dNeq(p1%at(x_ref),coef(1)))  error stop 'polynomial: @ref'
+
+  write(coef_s(1),*) coef(1)
+  write(coef_s(2),*) coef(2)
+  write(coef_s(3),*) coef(3)
+  write(x_ref_s,*) x_ref
+  write(x_s,*) x
+  YAML_s = 'C: '//trim(adjustl(coef_s(1)))//IO_EOL//&
+           'C,T: '//trim(adjustl(coef_s(2)))//IO_EOL//&
+           'C,T^2: '//trim(adjustl(coef_s(3)))//IO_EOL//&
+           'T_ref: '//trim(adjustl(x_ref_s))//IO_EOL
+  Dict => YAML_parse_str(trim(YAML_s))
+  p2 = polynomial(dict%asDict(),'C','T')
+  if (dNeq(p1%at(x),p2%at(x),1.0e-12_pReal))                      error stop 'polynomials: init'
+
+  p1 = polynomial(coef*[0.0_pReal,1.0_pReal,0.0_pReal],x_ref)
+  if (dNeq(p1%at(x_ref+x),-p1%at(x_ref-x),1.0e-10_pReal))         error stop 'polynomials: eval(odd)'
+  if (dNeq(p1%der1_at(x),p1%der1_at(5.0_pReal*x),1.0e-10_pReal))  error stop 'polynomials: eval_der(odd)'
+
+  p1 = polynomial(coef*[0.0_pReal,0.0_pReal,1.0_pReal],x_ref)
+  if (dNeq(p1%at(x_ref+x),p1%at(x_ref-x),1e-10_pReal))            error stop 'polynomials: eval(even)'
+  if (dNeq(p1%der1_at(x_ref+x),-p1%der1_at(x_ref-x),1e-10_pReal)) error stop 'polynomials: eval_der(even)'
+
+
+end subroutine selfTest
+
+end module polynomials