diff --git a/src/materials/assignment_converter.py b/src/materials/assignment_converter.py
index e397304cad5ad714bbc7799fbae475013e7223fb..690cd4f83b3d2569455fdd0a9afce02b1802ff2e 100644
--- a/src/materials/assignment_converter.py
+++ b/src/materials/assignment_converter.py
@@ -3,6 +3,7 @@ import sympy as sp
 import pystencils as ps
 from typing import List, Dict, Tuple, Union
 from pystencils.types.quick import Arr, Fp
+from pystencils.types import create_type
 from pystencils.sympyextensions.typed_sympy import CastFunc
 from src.materials.typedefs import Assignment, ArrayTypes
 
@@ -27,9 +28,9 @@ def type_mapping(type_str: str, length: int) -> Union[np.dtype, Arr]:
         dtype('float64')
     """
     if type_str == "double[]":
-        return Arr(Fp(64, const=True), length=length)  # 64-bit floating point array
+        return Arr(Fp(64, const=True), length)  # 64-bit floating point array
     elif type_str == "float[]":
-        return Arr(Fp(32, const=True), length=length)  # 32-bit floating point array
+        return Arr(Fp(32, const=True), length)  # 32-bit floating point array
     elif type_str == "double":
         return np.dtype('float64')
     elif type_str == "float":