New geometry class (#2103)

* Added 1D geometry class

* added r_inner, r_outer, v_inner, v_outer, volume

* Converting radius and velocity to cgs numpy arrays

* Made docstring more specific

* Removed dataframe and restructure properties

* Removed radius and velocity

* Added test for volume

* Updated docstring

* Fixed formatting

tardis/model/base.py

@@ -84,6 +84,29 @@ def r_outer(self):
         return self.geometry.r_outer.values * self.geometry_units["r_outer"]
 
 
+class Radial1DGeometry:
+    """
+    Holds information about model geometry for radial 1D models.
+
+    Parameters
+    ----------
+    r_inner : astropy.units.quantity.Quantity
+    r_outer : astropy.units.quantity.Quantity
+    v_inner : astropy.units.quantity.Quantity
+    v_outer : astropy.units.quantity.Quantity
+    """
+
+    def __init__(self, r_inner, r_outer, v_inner, v_outer):
+        self.r_inner = r_inner
+        self.r_outer = r_outer
+        self.v_inner = v_inner
+        self.v_outer = v_outer
+
+    @property
+    def volume(self):
+        return (4.0 / 3) * np.pi * (self.r_outer**3 - self.r_inner**3)
+
+
 class Composition:
     """
     Holds information about model composition

tardis/model/tests/test_base.py

@@ -5,7 +5,7 @@
 from numpy.testing import assert_almost_equal, assert_array_almost_equal
 
 from tardis.io.config_reader import Configuration
-from tardis.model import Radial1DModel
+from tardis.model import Radial1DModel, Radial1DGeometry
 from tardis.io.decay import IsotopeAbundances
 from tardis.model.base import Composition
 from tardis.simulation.base import Simulation
@@ -381,6 +381,26 @@ def test_density(self):
         )
 
 
+@pytest.mark.parametrize(
+    ("index", "expected"),
+    [
+        (0, 1.00977478e45),
+        (10, 1.98154804e45),
+        (19, 3.13361319e45),
+    ],
+)
+def test_radial_1D_geometry_volume(simulation_verysimple, index, expected):
+    sim = simulation_verysimple
+    model = sim.model
+    geometry = Radial1DGeometry(
+        model.r_inner, model.r_outer, model.v_inner, model.v_outer
+    )
+    volume = geometry.volume
+
+    assert volume.unit == u.Unit("cm3")
+    assert_almost_equal(volume[index].value, expected, decimal=-40)
+
+
 @pytest.mark.parametrize(
     ("index", "expected"),
     [