Quantity (RealwithUnit) unit converter using pint module

setup.py

@@ -30,6 +30,7 @@
     "appdirs>=1.4.0",
     "pandas>=1.1.5",
     "h5py>=3.7.0",
+    "pint>=0.18",
 ]
 
 

src/ansys/fluent/core/quantity.py

@@ -0,0 +1,137 @@
+import pint
+from pint import Unit
+
+ureg = pint.UnitRegistry(autoconvert_offset_to_baseunit=True)
+ureg.default_system = "SI"
+
+quantity = ureg.Quantity
+
+
+class Quantity(float):
+    """This class instantiates physical quantities using their real values and
+    units. Attributes of every instance of this class are used to construct a
+    new quantity instance supported by unit registry of pint module.
+
+    Attributes
+    ----------
+    value: Real value
+        Value of quantity is stored as float.
+
+    unit: Unit string
+        Unit of quantity is stored as string.
+
+    Methods
+    -------
+    to(to_unit)
+        Converts to given unit string.
+
+    Returns
+    -------
+    Quantity instance.
+
+    The pint module supports methods for unit conversions, unit compatibility and
+    dimensionality check.
+
+    All the instances of this class are converted to base SI units system to have
+    consistency in all arithmetic operations.
+    """
+
+    def __new__(self, real_value, units_string):
+        return float.__new__(self, real_value)
+
+    def __init__(self, real_value, units_string):
+        float.__init__(real_value)
+        self.value = self.__float__()
+        self.unit = units_string
+        self._quantity = quantity(self.value, self.unit)
+        self._base_si_quantity = self._quantity.to_base_units()
+
+    def __str__(self):
+        return f'({self.value}, "{self.unit}")'
+
+    def __repr__(self):
+        return f'(Quantity ({self.value}, "{self.unit}"))'
+
+    def to(self, to_unit):
+
+        """This method checks the compatibility between current instance unit
+        and user provided unit, if both of them are compatible, then only it
+        performs required conversion otherwise raises a Value Error."""
+
+        user_unit = Unit(to_unit)
+
+        if not self._quantity.is_compatible_with(user_unit):
+            raise ValueError("Units are not compatible.")
+
+        converted = self._quantity.to(to_unit)
+
+        return Quantity(converted.magnitude, to_unit)
+
+    def __mul__(self, other):
+
+        if isinstance(other, Quantity):
+            temp = self._base_si_quantity * other._quantity
+        elif isinstance(other, int) or isinstance(other, float):
+            temp = quantity(self._base_si_quantity * other, self.unit)
+        return Quantity(temp.magnitude, temp.units)
+
+    def __rmul__(self, other):
+        return self.__mul__(other)
+
+    def __truediv__(self, other):
+
+        if isinstance(other, Quantity):
+            temp = self._base_si_quantity / other._quantity
+        elif isinstance(other, int) or isinstance(other, float):
+            temp = quantity(self._base_si_quantity / other, self.unit)
+        return Quantity(temp.magnitude, temp.units)
+
+    def __add__(self, other):
+
+        if isinstance(other, Quantity):
+            temp = self._base_si_quantity + other._quantity
+        elif self._base_si_quantity.dimensionless and (
+            isinstance(other, int) or isinstance(other, float)
+        ):
+            temp = quantity(
+                self._base_si_quantity.magnitude + other, self._base_si_quantity.units
+            )
+        else:
+            raise ValueError(f"Quantity{(self.value, self.unit)} is not dimensionless.")
+        return Quantity(temp.magnitude, temp.units)
+
+    def __radd__(self, other):
+        return self.__add__(other)
+
+    def __sub__(self, other):
+
+        if isinstance(other, Quantity):
+            temp = self._base_si_quantity - other._quantity
+        elif self._base_si_quantity.dimensionless and (
+            isinstance(other, int) or isinstance(other, float)
+        ):
+            temp = quantity(
+                self._base_si_quantity.magnitude - other, self._base_si_quantity.units
+            )
+        else:
+            raise ValueError(f"Quantity{(self.value, self.unit)} is not dimensionless.")
+        return Quantity(temp.magnitude, temp.units)
+
+    def __rsub__(self, other):
+
+        if isinstance(other, Quantity):
+            temp = other._quantity - self._base_si_quantity
+        elif self._base_si_quantity.dimensionless and (
+            isinstance(other, int) or isinstance(other, float)
+        ):
+            temp = quantity(
+                other - self._base_si_quantity.magnitude, self._base_si_quantity.units
+            )
+        else:
+            raise ValueError(f"Quantity{(self.value, self.unit)} is not dimensionless.")
+        return Quantity(temp.magnitude, temp.units)
+
+    def __eq__(self, other):
+        return (
+            other._quantity == self._quantity if isinstance(other, Quantity) else False
+        )