GPU Accelerated Spectra

Example using GPU calculation with eq_spectrum_gpu()

Note

Systems with a dedicated GPU often have multiple devices available, because they also have an integrated GPU in the main processor. This can be selected by chosing a different device_id (e.g. ‘nvidia’ or ‘intel’). The device id could be a string or an integer. The integer is the device number, starting from 0. Look at the device overview printed when running the GPU spectrum to see what options are available.

Make sure to call gpu_exit() at the end to release all GPU resources. This can’t be done automatically because Radis doesn’t know how long you want to keep using the GPU. If you want to immediately exit the GPU calculations, the keyword exit_gpu=True can be passed to sf.eq_spectrum_gpu(), but this is uncommon because it doesn’t leverage the full power of GPU calculations.

--------------------------------------------------------------------------------
CO2 - HITRAN - Downloading database
--------------------------------------------------------------------------------

Download:
- All files already downloaded.

Caching to HDF5/H5 format:
- All files already cached.
0.04s - Loaded database
/home/docs/checkouts/readthedocs.org/user_builds/radis/checkouts/develop/radis/misc/warning.py:434: HighTemperatureWarning: HITRAN is valid for low temperatures (typically < 700 K). For higher temperatures you may need HITEMP or CDSD. See the 'databank=' parameter
  warnings.warn(WarningType(message))
Calculating Equilibrium Spectrum
Physical Conditions
----------------------------------------
   Tgas                 1500.0 K
   isotope              1
   medium               air
   mole_fraction        0.8
   path_length          0.2 cm
   pressure             1.0 bar
   self_absorption      True
   species              CO2
   state                X
   wavenum_max          2450.0000 cm-1
   wavenum_min          2150.0000 cm-1
Computation Parameters
----------------------------------------
   Tref                 296 K
   add_at_used          numpy
   broadening_method    voigt_poly
   cutoff               0 cm-1/(#.cm-2)
   dbformat             hitran
   dbpath               /home/docs/.radisdb/hitran/CO2.h5
   diluent              air
   folding_thresh       1e-06
   include_neighbouring_lines  True
   isatom               False
   isneutral            None
   lbfunc               None
   memory_mapping_engine  auto
   neighbour_lines      0 cm-1
   optimization         simple
   parsum_mode          full summation
   pfsource             default
   potential_lowering   None
   pseudo_continuum_threshold  0
   sparse_ldm           True
   truncation           50 cm-1
   waveunit             cm-1
   wstep                0.002 cm-1
   zero_padding         150001
----------------------------------------
0.10s - Spectrum calculated
Slice 1/1
/home/docs/checkouts/readthedocs.org/user_builds/radis/checkouts/develop/radis/misc/warning.py:434: HighTemperatureWarning: HITRAN is valid for low temperatures (typically < 700 K). For higher temperatures you may need HITEMP or CDSD. See the 'databank=' parameter
  warnings.warn(WarningType(message))
Vulkan version:  1.3.275.1
Selected device (device_id = 0):
[X] 0: llvmpipe (LLVM 15.0.7, 256 bits)

Finished calculating spectrum!
6.85s - Spectrum calculated
Slice 1/1

(<Figure size 640x480 with 2 Axes>, [<Axes: >, <Axes: xlabel='Wavelength (nm)'>])

from radis import SpectrumFactory, plot_diff

sf = SpectrumFactory(
    2150,
    2450,  # cm-1
    molecule="CO2",
    isotope="1",
    wstep=0.002,
)

sf.fetch_databank(
    source="hitran"
)  # use hitemp or exomol for accuracy at high tempertatures

T = 1500.0  # K
p = 1.0  # bar
x = 0.8
l = 0.2  # cm
w_slit = 0.5  # cm-1

s_cpu = sf.eq_spectrum(
    name="CPU",
    Tgas=T,
    pressure=p,
    mole_fraction=x,
    path_length=l,
)
s_cpu.apply_slit(w_slit, unit="cm-1")

s_gpu = sf.eq_spectrum_gpu(
    name="GPU",
    Tgas=T,
    pressure=p,
    mole_fraction=x,
    path_length=l,
    # device_id='nvidia',
    exit_gpu=True,
)
s_gpu.apply_slit(w_slit, unit="cm-1")

plot_diff(s_cpu, s_gpu, var="emissivity", wunit="nm", method="diff")

# s_gpu.exit_gpu()