eradiate.scenes.spectra.Spectrum

class eradiate.scenes.spectra.Spectrum(id=None, quantity=None)

Bases: NodeSceneElement, ABC

Spectrum interface.

Parameters:

• id (str, optional) – Identifier of the current scene element.

• quantity (PhysicalQuantity or str, optional, default: None) – Physical quantity which the spectrum represents. The specified quantity must be one which varies with wavelength. See PhysicalQuantity.spectrum() for allowed values.

  Child classes should implement value units validation and conversion based on quantity.

Fields:

• id (str or None) – Identifier of the current scene element.

• quantity (PhysicalQuantity or None) – Physical quantity which the spectrum represents.

Warning

• This class is to be used as a mixin.

• Subclasses must implement eval_mono(), eval_ckd() and integral().

Notes

Leaving the quantity field unset is discouraged and permitted only to allow for more convenience in some parts of the code (e.g. to increase the flexibility of spectrum conversion protocols).

eval(si)

eval(si)

eval(si)

Evaluate spectrum at a given spectral index.

Parameters:

si (SpectralIndex) – Spectral index.

Returns:

value (quantity) – Evaluated spectrum.

Notes

This method dispatches evaluation to specialized methods depending on the spectral index type.

abstract eval_ckd(w, g)

Evaluate spectrum in CKD modes.

Parameters:

• w (quantity) – Spectral bin center wavelength.

• g (float) – Absorption coefficient cumulative probability.

Returns:

value (quantity) – Evaluated spectrum as an array with shape w.

Notes

It is assumed that w and g have the same shape. In CKD mode, it is assumed that all spectra—except that of the absorption coefficient—are uniform over the spectral bin. These spectra are evaluated at the spectral bin center wavelength.

abstract eval_mono(w)

Evaluate spectrum in monochromatic modes.

Parameters:

w (quantity) – Wavelength.

Returns:

value (quantity) – Evaluated spectrum as an array with the same shape as w.

integral(wmin, wmax)

Compute the integral of the spectrum on a given interval.

Parameters:

• wmin (quantity) – Integration interval’s lower bound.

• wmax (quantity) – Integration interval’s upper bound.

Returns:

value (quantity or ndarray) – Computed integral value, in units consistent with the specified quantity.

Warning

If the quantity field is unset (i.e. left to its default value None), the output of this method will inherit the units of value fields (the actual policy depends on the implementation, and unitless values are intepreted as dimnesionless). Note that leaving the quantity field unset is discouraged.

traverse(callback)

Traverse this scene element and collect kernel dictionary template and parameter update map contributions.

Parameters:

callback (SceneTraversal) – Callback data structure storing the collected data.

update()

Enforce internal state consistency. This method should be called when fields are modified. It is automatically called as a post-init step.

property objects

Map of child objects associated with this scene element.

Returns:

dict – A dictionary mapping object names to a corresponding object to be inserted in the Eradiate scene graph.

property params

Returns:

dict[str, UpdateParameter] or None – A dictionary mapping parameter paths, consisting of dot-separated strings, to a corresponding update protocol.

See also

UpdateParameter, UpdateMapTemplate

abstract property template

Kernel dictionary template contents associated with this scene element.

Returns:

dict – A flat dictionary mapping dot-separated strings describing the path of an item in the nested scene dictionary to values. Values may be objects which can be directly used by the mitsuba.load_dict() function, or InitParameter instances which must be rendered.

See also

InitParameter, KernelDictTemplate