S4Utils functions references

Created on Thu Apr 2 12:05:13 2020

@author: mathieu

Basic Utility functions

S4Utils.S4Utils.totuple(a)

Converts lists and array to a tuple form. Usefull since S4 mostly accepts tuples instead of numpy arrays.

Parameters

a (array-like, list or float) – Array-like parameter to cast to a tuple

Returns

ta – elements of a cast into a tuple of same ‘shape’.

Return type

tuple

Raises

TypeError: – If the type of a cannot be cast into a tuple form, returns a

S4Utils.S4Utils.UpdateMaterials(S, Mat_list, Eps_list, fi, f0)

Updates a Simulation to set all refractive indices at given frequency

Parameters

  • S (S4.Simulation) –

  • Mat_list (list) – list of string containing the name of the materials to update. These are typically the ones passes in the ‘Material’ argument for the S4.Simulation.SetMaterial() function

  • Eps_list (list) – list of arrays containing the permittivities. each element is a 1D array or a 3x3xlen(f) array

  • fi (float) – frequency at which the simulation is set (reduced units)

  • f0 (1Darray) – array of reduced frequencies over which the simulation runs

Return type

None.

Simulation Functions

2D Slicing functions

S4Utils.S4Utils.GetField_xy(S, res, zs)

Get E and H fields in an xy slice. Built-in S4 function that requires some care and a tweak, but extra efficient !!

Parameters

  • S (S4.Simulation) –

  • res (tuple) – (resx, resy) tuple of number of points along x and y Note that it corresponds to resy lines and resx columns

  • zs (float) – z-coordinate at which to slice the field

Return type

None.

S4Utils.S4Utils.GetField_xz(S, x, y, z, ys=0.0)

Get E and H fields in an xz slice. Wraps around GetField_xy which is hard-coded in the C code and thus much faster. BUT you should check that it matches with GetSlice at least once because the C function GetFieldsOnGrid tends to be touchy.

Parameters

  • S (S4.Simulation Object) – Simulation to run

  • x (1Darray) – 1Darray of x-coordinates

  • y (1Darray) – 1Darray of y-coordinates

  • z (1Darray) – 1Darray of z-coordinates

  • ys (float, optional) – y-coordinate of the slice. Defaults to 0 (center of the unit cell).

Returns

  • E_slice (len(z) by len(x) by 3 array) – Array of the electric field vector on the slice

  • H_slice (len(z) by len(x) by 3 array) – Array of the magnetic field vector on the slice

S4Utils.S4Utils.GetField_yz(S, x, y, z, xs=0.0)

Get E and H fields in an yz slice. Wraps around GetField_xy which is hard-coded in the C code and thus much faster. BUT you should check that it matches with GetSlice at least once because the C function GetFieldsOnGrid tends to be touchy.

Parameters

  • S (S4.Simulation Object) – Simulation to run

  • x (1Darray) – 1Darray of x-coordinates

  • y (1Darray) – 1Darray of y-coordinates

  • z (1Darray) – 1Darray of z-coordinates

  • xs (float, optional) – x-coordinate of the slice. Defaults to 0 (center of the unit cell).

Returns

  • E_slice (len(z) by len(y) by 3 array) – Array of the electric field vector on the slice

  • H_slice (len(z) by len(y) by 3 array) – Array of the magnetic field vector on the slice

S4Utils.S4Utils.GetSlice(S, ax1, ax2, axs=0, plane='xz', mode='All')

Slice field and/or epsilon in an arbitrary slice along 2 axis at a given position on the third. Point-by-point computation version. There is no built-in function for this, so it is much slower. However it is less ambiguous than the GetField methods and can be used to check/debug.

Parameters

  • S (S4.Simulation) –

  • ax1 (1Darray) – first axis to define the slice plane

  • ax2 (1Darray) – second axis to define the slice plane

  • axs (float) – coordinate along thirs axis on which to slice

  • plane (str) – ‘xz’, ‘yz’ or ‘xz’ to choose which slice it is

  • mode (str) – either ‘Field’, ‘Epsilon’, ‘All’ to choose which quantity to slice

3D Volume functions

S4Utils.S4Utils.GetFieldVolume(S, x, y, z)

Get the electric field vector in the whole simulation volume

Parameters

  • S (S4.Simulation obect) – Simulation object to run

  • x (1Darray) – 1Darray of x-coordinates

  • y (1Darray) – 1Darray of y-coordinates

  • z (1Darray) – 1Darray of z-coordinates

Returns

  • E_vol (len(x) by len(y) by len(z) by 3 array) – Array of electric field in the simulation volume

  • H_vol (len(x) by len(y) by len(z) by 3 array) – Array of magnetic field in the simulation volume

S4Utils.S4Utils.GetEpsilonVolume(S, x, y, z)

Get the reconstructed permittivity in the whole simulation volume

Parameters

  • S (S4.Simulation obect) – Simulation object to run

  • x (1Darray) – 1Darray of x-coordinates

  • y (1Darray) – 1Darray of y-coordinates

  • z (1Darray) – 1Darray of z-coordinates

Returns

Eps_vol – Array of the permittivity in the simulation volume

Return type

len(x) by len(y) by len(z) array

S4Utils Plotting Utilities

The SlicePlot class

class S4Utils.S4Utils.SlicePlot(a1, a2, Field, cmap=matplotlib.pyplot.cm.bwr, hcoord=None, vcoord=None, sym=True)

Helper to plot a slice with linecuts at arbitrary positions

Parameters

  • a1 (1Darray) – 1Darray for the horizontal axis of the 2D plot (typically x)

  • a2 (1Darray) – 1Darray for the vertical axis of the 2D plot (typically y or z)

  • Field (2Darray) – 2Darray to be plotted (len(a2) x len(a1))

  • cmap (matplotib.colors.Colormap object) – The colormap to pass to matplotlib.pcolormesh for plotting. Defaults to matplotlib.cm.bwr.

  • hcoord (float, optional) – Horizontal coordinate for the vertical slice. Defaults to the center of the axe coordinate array given (a1).

  • vcoord (float, optional) – Vertical coordinate for the horizontal slice. Defaults to the center of the axe coordinate array given (a2).

  • sym (bool, optional) – Flag to force symmetry in the colormap or leave it automated

a1

1Darray for the horizontal axis of the 2D plot (typically x)

Type

1Darray

a2

1Darray for the vertical axis of the 2D plot (typically y or z)

Type

1Darray

Field

2Darray to be plotted (len(a2) x len(a1))

Type

2Darray

hcoord

Horizontal coordinate for the vertical slice. Defaults to the center of the axe coordinate array given (a1).

Type

float, optional

vcoord

Vertical coordinate for the horizontal slice. Defaults to the center of the axe coordinate array given (a2).

Type

float, optional

sym

Flag to force symmetry in the colormap or leave it automated

Type

bool, optional

figslice

The matplotlib figure in which the plot is drawn

Type

matplotlib.figure

fignum

The number of the figure as retrieved by matplotlib.figure.number

Type

int

ax_2D

The axes in which the 2D slice is drawn

Type

matplotlib.axes

cax

The axes in which the colorbar for ax_2D drawn

Type

matplotlib.axes

ax_cbar

The matplotlib.colorbar instance

Type

matplotlib.colorbar

ax_a1slice

The axes in which the slice along a2 at a fixed a1 position is drawn

Type

matplotlib.axes

lv

The line of the vertical cut, e.g. along a2

Type

matplotlib.line

ax_a2slice

The axes in which the slice along a1 at a fixed a2 position is drawn

Type

matplotlib.axes

lh

The line of the horizontal cut, e.g. along a1

Type

matplotlib.line

lslice_h

The line showing the position of the horizontal slice in ax_2D

Type

matplotlib.line

lslice_v

The line showing the position of the vertical slice in ax_2D

Type

matplotlib.line

GUIButton

The button to hide/show the GUI

Type

matplotlib.widgets.CheckButtons

Notes

For a 3D stack of slices one should move to Plotly instead of matplotlib https://nbviewer.jupyter.org/github/empet/Plotly-plots/blob/master/Plotly-Slice-in-volumetric-data.ipynb

The GUISlicePlot class

class S4Utils.S4Utils.GUISlicePlot(parentfig)

Generates an auxiliary figure to interact with a SlicePlot. The GUI side plot allows to move the vertical and horizontal sliders to show slices at different locations.

Parameters

parentfig (S4Utils.S4Utils.SlicePlot instance) – The SlicePlot figure to which the GUI applies.

parentfig

The SlicePlot figure to which the GUI applies.

Type

S4Utils.S4Utils.SlicePlot instance

figGUI

The matplotlib.figure in which the GUI is drawn

Type

matplotlib.figure instance

ax1

The axes for the first slider linked to parentfig.a1

Type

matplotlib.axes

ax2

The axes for the first slider linked to parentfig.a2

Type

matplotlib.axes

Sl_ax1

The slider linked to the parentfig.a1 axis

Type

matplotlib.widgets.Slider

Sl_ax2

The slider linked to the parentfig.a2 axis

Type

matplotlib.widgets.Slider

Return type

None.

Todo

Add a frequency input textbox to change the frequency and update plot

3D Plotting Function

S4Utils.S4Utils.Plot3DSlices(axes, DataVol, points, InteractiveSlices=False)

3D rendering of 3 slices in orthogonal planes.

Parameters

  • axes – x, y and z 1Darray vectors of coordinates on which the data is calculated. Usually passed as (x,y,z) or np.array((x,y,z))

  • DataVol (len(x) by len(y) by len(z) numpy array) – Volumetric data in numpy array to be plotted Usually obtained using S4Utils.S4Utils.GetFieldVolume() or S4Utils.S4Utils.GetEpsilonVolume() functions.

  • points (tuple, list or array) – point at which to slice the volume data. Usually (xs, ys, zs), in real space coordinates

  • InteractiveSlices (bool (opt)) – Boolean flag to activate PyVista’s defaults 3D slicing. Defaults to False.

Return type

None.

Notes

Follows https://docs.pyvista.org/examples/00-load/create-uniform-grid.html and https://docs.pyvista.org/plotting/widgets.html#pyvista.WidgetHelper.add_mesh_slice_orthogonal