swiftsimio.visualisation.slice_backends.nearest_neighbours module

Backend tools for image slices with nearest neighbour interpolation.

swiftsimio.visualisation.slice_backends.nearest_neighbours.build_tree(x: float64, y: float64, z: float64, box_x: float, box_y: float, box_z: float) → None[source]

Build the tree used for the nearest-neighbour calculations.

In the periodic case, we must make sure that all particle coordinates fall inside the box.

Parameters:

x (array of float64) – The x-positions of the particles. Must be bounded by [0, 1].
y (array of float64) – The y-positions of the particles. Must be bounded by [0, 1].
z (array of float64) – The z-positions of the particles. Must be bounded by [0, 1].
box_x (float) – Box size in x, in the same rescaled length units as x, y and z. Used for periodic wrapping (if not 0).
box_y (float) – Box size in y, in the same rescaled length units as x, y and z. Used for periodic wrapping (if not 0).
box_z (float) – Box size in z, in the same rescaled length units as x, y and z. Used for periodic wrapping (if not 0).

Returns:

A KD-tree built from the particle positions.

Return type:

KDTree

swiftsimio.visualisation.slice_backends.nearest_neighbours.slice_scatter(x: float64, y: float64, z: float64, m: float32, h: float32, z_slice: float, xres: int, yres: int, box_x: float = 0.0, box_y: float = 0.0, box_z: float = 0.0, workers: int = 1) → ndarray[source]

Create a 2D image slice through a volume.

Creates a 2D numpy array (image) of the given quantities of all particles in a data slice including periodic boundary effects.

Parameters:

x (array of float64) – The x-positions of the particles. Must be bounded by [0, 1].
y (array of float64) – The y-positions of the particles. Must be bounded by [0, 1].
z (array of float64) – The z-positions of the particles. Must be bounded by [0, 1].
m (array of float32) – Masses (or otherwise weights) of the particles.
h (array of float32) – Smoothing lengths of the particles.
z_slice (float64) – The position at which we wish to create the slice.
xres (int) – The number of pixels in x direction.
yres (int) – The number of pixels in the y direction.
box_x (float) – Box size in x, in the same rescaled length units as x, y and z. Used for periodic wrapping (if not 0).
box_y (float) – Box size in y, in the same rescaled length units as x, y and z. Used for periodic wrapping (if not 0).
box_z (float) – Box size in z, in the same rescaled length units as x, y and z. Used for periodic wrapping (if not 0).
workers (int) – The number of workers to use for the nearest-neighbour calculations. Set to -1 to use all available cpus.

Returns:

Output array for the slice image.

Return type:

ndarray of float32