StratifiedGeometry

This class defines a stratified geometry, such as geological layers, represented by a collection of GeometrySector. The layers are separated by TopographySurface objects. Within each layer, a uniform atomic composition is assumed, specified by a MaterialDefinition. The density might vary as a DensityGradient.

Constructor

class StratifiedGeometry(*args: GeometrySector | TopographySurface)

Creates a stratified Monte Carlo geometry from a sequence of alternating GeometrySector and TopographySurface objects. The geometry is specified in reading order, with the first element of the sequence located on top of the geometry. For instance, the following

>>> geometry = goupil.StratifiedGeometry(
...     goupil.GeometrySector("N2", 1.205E-03, "Atmosphere"),
...     water_surface,
...     goupil.GeometrySector("H2O", 1.0, "Water"),
...     soil_surface,
...     goupil.GeometrySector("SiO2", 2.0, "Soil")
... )

defines a vertical section of water covered by a nitrogen atmosphere and bounded below by a sandy soil.

Note

In the previous example, the soil_surface may extend above the water_surface. This means that lower layers take precedence over higher ones in case of overlaps.

Attributes

Note

The attributes of a StratifiedGeometry are read-only. Any modifications require rebuilding the geometry object.

StratifiedGeometry.materials: tuple[MaterialDefinition]

This attribute lists all geometry materials as a tuple.

StratifiedGeometry.sectors: tuple[GeometrySector]

This attribute lists all geometry sectors as a tuple.

Warning

Geometry sectors are stored in indexing order. That is, sectors[0] corresponds to the bottom layer.

Methods

StratifiedGeometry.locate(states) → numpy.ndarray

Locates the specified states within the geometry. The input states must be a structured numpy.ndarray containing the "position" field, e.g. as returned by the states function. Upon completion, the function returns a numpy.ndarray of sector indices.

StratifiedGeometry.material_index(name) → int

Returns the index of a material in the list of geometry materials based on its name. For instance

>>> geometry.material_index("SiO2")
0

StratifiedGeometry.sector_index(description) → int

Returns the index of a sector in the list of geometry sectors based on its description. For instance

>>> geometry.sector_index("Atmosphere")
2

StratifiedGeometry.trace(states, lengths=None, density=None) → numpy.ndarray

Casts rays through the geometry, starting from the specified states. The states must be a structured numpy.ndarray containing the "position" and "direction" fields, e.g. as returned by the states function. Upon completion, this function returns a numpy.ndarray containing the path length of rays in each geometry sector. Optionally, you can provide a lengths numpy.ndarray of floats, or a single float, indicating the lengths of rays. If no lengths are specified, rays are traced until the geometry outer boundary.

If the density parameter is set to True, this function will return the column depth (grammage) along rays, in each sector, rather than the path length.

Note

The Turtle algorithm is used to perform ray tracing. For more information, refer to [NBCM20].

StratifiedGeometry.z(x, y, grid=None) → numpy.ndarray

Returns the elevation values of each TopographySurface at coordinates \((x, y)\). The x and y arguments can be float or numpy.ndarray with consistent sizes. If grid is set to True, elevation values are computed over a grid that corresponds to the outer product of x and y, similar to the TopographyMap.__call__() method.