dft working with dask but not withouth

The following works:

import numpy as np
import xarray as xr
import xrft

ds = xr.Dataset(coords={'time': ('time', np.arange(3000)*3600.), 'depth': ('depth', np.arange(10))})
ds = ds.assign(u=np.cos(2.*np.pi*2/86400.*ds.time)+0.*ds.depth)

ds = ds.chunk({'depth': 1})
u_fft = xrft.dft(ds.u.fillna(0.), dim=['time'], shift=False, detrend='linear', window=True)
print(u_fft.values)

But turning off chunking does not work:

import numpy as np
import xarray as xr
import xrft

ds = xr.Dataset(coords={'time': ('time', np.arange(3000)*3600.), 'depth': ('depth', np.arange(10))})
ds = ds.assign(u=np.cos(2.*np.pi*2/86400.*ds.time)+0.*ds.depth)

#ds = ds.chunk({'depth': 1})
u_fft = xrft.dft(ds.u.fillna(0.), dim=['time'], shift=False, detrend='linear', window=True)
print(u_fft.values)

And leads to:

(equinox) r2i2n0 datahome/aponte% python test_rft.py
Traceback (most recent call last):
  File "test_rft.py", line 9, in <module>
    u_fft = xrft.dft(ds.u.fillna(0.), dim=['time'], shift=False, detrend='linear', window=True)
  File "/home1/datahome/aponte/xrft/xrft/xrft.py", line 238, in dft
    da = _apply_detrend(da, axis_num)
  File "/home1/datahome/aponte/xrft/xrft/xrft.py", line 156, in _apply_detrend
    da = detrendn(da, axes=axis_num)
  File "/home1/datahome/aponte/xrft/xrft/xrft.py", line 100, in detrendn
    raise NotImplementedError("Detrending over more than 4 axes is "
NotImplementedError: Detrending over more than 4 axes is not implemented.

This looks like a bug but I could not decipher xrft enough in order to fix it.

[rabernat]

It’s great when bugs fix themselves! 😄

[roxyboy]

I’m going to close this issue since the current version of xrft doesn’t seem to produce this error.