GPU Accelerated Spectra (recalc_gpu() demo)

Example using GPU calculation with recalc_gpu()

After producing a spectrum object with sf.eq_spectrum_gpu(), new spectra can be produced quickly with spectrum.recalc_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.

--------------------------------------------------------------------------------
CO - HITRAN - Downloading database
--------------------------------------------------------------------------------

Download:
- All files already downloaded.

Caching to HDF5/H5 format:
- All files already cached.
0.03s - Loaded database
/home/docs/checkouts/readthedocs.org/user_builds/radis/checkouts/latest/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!
0.67s - Spectrum calculated
Slice 1/1
Plot0 finished in  667.7 ms
Plot1 finished in  190.1 ms
Slice 1/1
Plot2 finished in  188.6 ms
Slice 1/1
Plot3 finished in  193.8 ms
Slice 1/1
Plot4 finished in  191.5 ms
Slice 1/1

from radis import SpectrumFactory

sf = SpectrumFactory(
    2150,
    2450,  # cm-1
    # molecule="CO2",
    molecule="CO",
    isotope="1,2,3",
    wstep=0.002,
)


sf.fetch_databank("hitran")
##sf.fetch_databank("exomol")

T_list = [1000.0, 1250.0, 1500.0, 1750.0, 2000.0]

s = sf.eq_spectrum_gpu(
    Tgas=T_list[0],  # K
    pressure=1,  # bar
    mole_fraction=0.8,
    path_length=0.2,  # cm
    # device_id='intel',
    # device_id='nvidia',
)
s.apply_slit(0.5, unit="cm-1")  # cm-1
print(f"Plot0 finished in {s.conditions['calculation_time'] * 1e3:6.1f} ms")
s.plot("radiance", wunit="nm", show=False)

for i, T in enumerate(T_list[1:]):
    s.recalc_gpu(Tgas=T)
    print(f"Plot{i + 1:d} finished in {s.conditions['calculation_time'] * 1e3:6.1f} ms")
    show = True if T == T_list[-1] else False
    s.plot("radiance", wunit="nm", show=show, nfig="same")

s.exit_gpu()