fix readme

Author: agrouaze

README.md

@@ -6,27 +6,30 @@ momentum spectrum decomposition
 ## open a .nc file containing spectral data
 ```python
 import datatree
-file_L1b = '/home1/scratch/agrouaze/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'
+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
-one_spec_re = dt['intraburst_xspectra'].ds['xspectra_2tau_Re'].isel(burst=0,
-                                                tile_sample=0,tile_line=0).mean(dim='2tau')
-one_spec_im = dt['intraburst_xspectra'].ds['xspectra_2tau_Im'].isel(burst=0,
-                                                tile_sample=0,tile_line=0).mean(dim='2tau')
+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)
-one_spec_re = one_spec_re.swap_dims({'freq_sample':'k_rg','freq_line':'k_az'})
-one_spec_re = spectrum_momentum.symmetrize_xspectrum(one_spec_re, dim_range='k_rg', dim_azimuth='k_az')
-one_spec_im = one_spec_im.swap_dims({'freq_sample':'k_rg','freq_line':'k_az'})
-one_spec_im = spectrum_momentum.symmetrize_xspectrum(one_spec_im, dim_range='k_rg', dim_azimuth='k_az')
-one_spec_re
+
 ```
 
-## compute 20 orthogonal momentum
+## 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,