radis.los.slabs module¶

Summary¶

Classes to deal with multi-slabs configurations:

MergeSlabs() for several species at the same spatial position
SerialSlabs() to add several spectra along the line-of-path

One Slab is just a Spectrum object .. rubric:: Examples

See more examples in the RADIS line-of-sight module ——————————————————————————-

MergeSlabs(*slabs, **kwargs) → Spectrum[source]¶

Combines several slabs into one. Useful to calculate multi-gas slabs. Linear absorption coefficient is calculated as the sum of all linear absorption coefficients, and the RTE is recalculated to get the total radiance. You can also simply use:

s1//s2

Merged spectrum 1+2 is calculated with Eqn (4.3) of the [RADIS-2018] article, generalized to N slabs :

\[ \begin{align}\begin{aligned}j_{\lambda, 1+2} = j_{\lambda, 1} + j_{\lambda, 2}\\k_{\lambda, 1+2} = k_{\lambda, 1} + k_{\lambda, 2}\end{aligned}\end{align} \]

where

\[j_{\lambda}, k_{\lambda}\]

are the emission coefficient and absorption coefficient of the two slabs 1 and 2. Emission and absorption coefficients are calculated if not given in the initial slabs (if possible).

Parameters:

slabs (list of Spectra, each representing a slab) – path_length must be given in Spectrum conditions, and equal for all spectra.

line-of-sight:

slabs
            [0]        \====
light       [1]  ->     )===  observer
            [n]        /====

Other Parameters:

kwargs input
resample ('never', 'intersect', 'full') – what to do when spectra have different wavespaces:
- If 'never', raises an error
- If 'intersect', uses the intersection of all ranges, and resample spectra on the most resolved wavespace.
- If 'full', uses the overlap of all ranges, resample spectra on the most resolved wavespace, and fill missing data with 0 emission and 0 absorption
Default 'never'
out ('transparent', 'nan', 'error') – what to do if resampling is out of bounds:
- 'transparent': fills with transparent medium.
- 'nan': fills with nan.
- 'error': raises an error.
Default 'nan'
optically_thin (boolean) – if True, merge slabs in optically thin mode. Default False
verbose (boolean) – if True, print messages and warnings. Default False
modify_inputs (False) – if True, slabs are modified directly when they are resampled. This avoids making a copy so is slightly faster. Default False.

Returns:

Spectrum – observed at the output. Conditions and units are transported too, unless there is a mismatch then conditions are dropped (and units mismatch raises an error because it doesnt make sense)

Return type:

object representing total emission and total transmittance as

Examples

Merge two spectra calculated with different species (physically correct only if broadening coefficients dont change much):

from radis import calc_spectrum, MergeSlabs
s1 = calc_spectrum(...)
s2 = calc_spectrum(...)
s3 = MergeSlabs(s1, s2)

The last line is equivalent to:

s3 = s1//s2

Load a spectrum precalculated on several partial spectral ranges, for a same molecule (i.e, partial spectra are optically thin on the rest of the spectral range):

from radis import load_spec, MergeSlabs
spectra = []
for f in ['spec1.spec', 'spec2.spec', ...]:
    spectra.append(load_spec(f))
s = MergeSlabs(*spectra, resample='full', out='transparent')
s.update()   # Generate missing spectral quantities
s.plot()

Calculate a large spectrum by part

SerialSlabs(*slabs: Spectrum, **kwargs: dict) → Spectrum[source]¶

Adds several slabs along the line-of-sight. If adding two slabs only, you can also use:

s1>s2

Serial spectrum 1>2 is calculated with Eqn (4.2) of the [RADIS-2018] article, generalized to N slabs :

\[ \begin{align}\begin{aligned}I_{\lambda, 1>2} = I_{\lambda, 1} \tau_{\lambda, 2} + I_{\lambda, 2}\\\tau_{\lambda, 1+2} = \tau_{\lambda, 1} \cdot \tau_{\lambda, 2}\end{aligned}\end{align} \]

where

\[I_{\lambda}, \tau_{\lambda}\]

are the radiance and transmittance of the two slabs 1 and 2. Radiance and transmittance are calculated if not given in the initial slabs (if possible).

Parameters:

slabs (list of Spectra, each representing a slab) –

line-of-sight:

slabs       [0]     [1]  ............... [n]
             :       :                    :         \====
light        *   ->  *        ->          *    ->    )===  observer
                                                    /====

resample_wavespace ('never', 'intersect', 'full') – what to do when spectra have different wavespaces:
- If 'never', raises an error
- If 'intersect', uses the intersection of all ranges, and resample spectra on the most resolved wavespace.
- If 'full’, uses the overlap of all ranges, resample spectra on the most resolved wavespace, and fill missing data with 0 emission and 0 absorption
Default 'never'
out ('transparent', 'nan', 'error') – what to do if resampling is out of bounds:
- 'transparent': fills with transparent medium.
- 'nan': fills with nan.
- 'error': raises an error.
Default 'nan'

Other Parameters:

verbose (bool) – if True, more blabla. Default False
modify_inputs (False) – if True, slabs wavelengths/wavenumbers are modified directly when they are resampled. This avoids making a copy so it is slightly faster. Default False.

Note

for large number of slabs (in radiative transfer calculations) you surely want to use this option !

Returns:

Spectrum – observed at the output (slab[n+1]). Conditions and units are transported too, unless there is a mismatch then conditions are dropped (and units mismatch raises an error because it doesnt make sense)

Return type:

object representing total emission and total transmittance as

Examples

Add s1 and s2 along the line of sight: s1 –> s2:

s1 = calc_spectrum(...)
s2 = calc_spectrum(...)
s3 = SerialSlabs(s1, s2)

The last line is equivalent to:

s3 = s1>s2

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radis.los.slabs module¶

Summary¶