https://github.com/agrouaze/dspec

momentum spectrum decomposition
https://github.com/agrouaze/dspec

decomposition numpy orthogonal python3 spectral-analysis spectrum xarray

Last synced: about 1 month ago
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momentum spectrum decomposition

• Host: GitHub
• URL: https://github.com/agrouaze/dspec
• Owner: agrouaze
• License: mit
• Created: 2022-12-15T14:13:17.000Z (about 2 years ago)
• Default Branch: main
• Last Pushed: 2023-02-08T10:53:21.000Z (about 2 years ago)
• Last Synced: 2024-11-10T09:27:49.244Z (3 months ago)
• Topics: decomposition, numpy, orthogonal, python3, spectral-analysis, spectrum, xarray
• Language: Python
• Homepage:
• Size: 13.7 KB
• Stars: 2
• Watchers: 1
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# dspec

momentum spectrum decomposition

# Example of usage

## open a .nc file containing spectral data

```python

import datatree

file_L1b = './S1B_IW_SLC__1SDV_20210420T094142_20210420T094208_026549_032B99_7071.SAFE/s1b-iw3-slc-vv-20210420t094142-20210420t094208-026549-032b99-006_L1B_xspec_IFR_0.5.nc'

dt = datatree.open_datatree(file_L1b)

```

## symmetrize both imaginary and real part spectrum 

```python

import spectrum_momentum

cat_xspec = 'intra'

ds = dt[cat_xspec+'burst_xspectra'].to_dataset()

for tautau in range(3):

    ds['xspectra_%stau'%tautau] = ds['xspectra_%stau_Re'%tautau] + 1j*ds['xspectra_%stau_Im'%tautau]

    ds = ds.drop(['xspectra_%stau_Re'%tautau,'xspectra_%stau_Im'%tautau])

xspec2tau  =  ds['xspectra_2tau'].swap_dims({'freq_sample':'k_rg','freq_line':'k_az'})

xspec2tau = spectrum_momentum.symmetrize_xspectrum(xspec2tau, dim_range='k_rg', dim_azimuth='k_az')

one_spec_re = xspec2tau.isel(burst=0,tile_sample=0,tile_line=0).mean(dim='2tau').real

one_spec_im = xspec2tau.isel(burst=0,tile_sample=0,tile_line=0).mean(dim='2tau').imag

print(one_spec_re)

```

## compute 20 orthogonal momentum (floats) associated to convolution of the spectra with weights

```python

import spectrum_momentum

decomp_moments = spectrum_momentum.orthogonalDecompSpec(real_part_spectrum=one_spec_re,

                                                        imaginary_part_spectrum=one_spec_im)

decomp_moments

```