Interpolate_1d does not function with Type Error ( tuple indices must be integers or slices, not tuple)

[sunchaoatmo]

Bugs

• Code Sample, from the official website:
  https://unidata.github.io/MetPy/latest/api/generated/metpy.interpolate.log_interpolate_1d.html#metpy.interpolate.log_interpolate_1d

  1 #!/usr/bin/env python
  2 import numpy as np
  3 import metpy.interpolate
  4 x_log = np.array([1e3, 1e4, 1e5, 1e6])
  5 y_log = np.log(x_log) * 2 + 3
  6 x_interp = np.array([5e3, 5e4, 5e5])
  7 print(metpy.interpolate.log_interpolate_1d(x_interp, x_log, y_log))

• Problem description: the code can not run with the error message as follow:
  Traceback (most recent call last):
  File "./test.py", line 7, in
  print(metpy.interpolate.log_interpolate_1d(x_interp, x_log, y_log))
  File "/Users/chaosun/anaconda3/lib/python3.7/site-packages/metpy/xarray.py", line 436, in wrapper
  return func(*args, **kwargs)
  File "/Users/chaosun/anaconda3/lib/python3.7/site-packages/pint/registry_helpers.py", line 194, in wrapper
  result = func(*new_values, **kw)
  File "/Users/chaosun/anaconda3/lib/python3.7/site-packages/metpy/interpolate/one_dimension.py", line 228, in log_interpolate_1d
  return interpolate_1d(log_x, log_xp, *args, axis=axis, fill_value=fill_value)
  File "/Users/chaosun/anaconda3/lib/python3.7/site-packages/metpy/xarray.py", line 436, in wrapper
  return func(*args, **kwargs)
  File "/Users/chaosun/anaconda3/lib/python3.7/site-packages/pint/registry_helpers.py", line 194, in wrapper
  result = func(*new_values, **kw)
  File "/Users/chaosun/anaconda3/lib/python3.7/site-packages/metpy/interpolate/one_dimension.py", line 119, in interpolate_1d
  variables = [arr[sorter] for arr in args]
  File "/Users/chaosun/anaconda3/lib/python3.7/site-packages/metpy/interpolate/one_dimension.py", line 119, in
  variables = [arr[sorter] for arr in args]
  TypeError: tuple indices must be integers or slices, not tuple

• Versions:

  • We tested 3.7.1, 3.6.8, 2.7.15
  • Platform Mac and Linux (Cheyenne CISL supercomputer )
  • metpy version: 0.10.0 0.9.0 0.8.0

[dopplershift]

So the problem is caused by pint 0.9. As a work-around for now, I'd suggest installing pint 0.8.1.

[MethaneRain]

I'm experiencing the same problem with mpcalc.isentropic_interpolation as of recently as well. Would downgrading the pint work, or should I open a new issue for my specific issue?

[jrleeman]

Pint 0.9 fundamentally breaks a lot of things, so I'd roll to 0.8.1

[MethaneRain]

What would be the best way to do that, through conda or pip?

[jrleeman]

I lean to conda, so conda install pint=0.8.1

[MethaneRain]

I downgraded pint but unfortunately I'm now running into a different issue when trying to pull data from the GFS via thredds and ncss...

Curious if anyone else has succeeded in downgrading with no errors

Edit

Looks like something with netcdf4 library changed from downgrade?

[dopplershift]

That’s weird. Could try conda update netcdf4

[MethaneRain]

I remembered I messed around with NCL and pygrib around the time of pint upgrade to 0.9. So went back in time and got back to originally having 0.8.1 before NCL/pygrib, then upgraded to 0.9, got the error again. This time going back to 0.8.1 w/o NCL or pygrib I was able to successfully run off 0.8.1 without any troubles from netcdf4.

So I'm good, and have my isentropes again.

Thanks as always for the pointers!

[jbellier]

I have started yesterday to use Metpy, and the current default installation (as of May 29 2019) installs pint=0.9. I was trying to use the function storm_relative_helicity() but got the same Type Error ( tuple indices must be integers or slices, not tuple). It took me a while to figure out that it came from the pint version.

I don't know if solving this issue is planned, but in the meantime I would suggest to update the descriptions of the impacted functions so that we know we have to use pint=0.8.1.

By the way, conda install pint=0.8.1 does not work anymore, I had to download manually the version from the release history of pint.

[dopplershift]

We’ll have a fix in the next release, sorry that that’s been lagging so long. Does this work to install pint: conda install -c conda-forge pint?

[jbellier]

Well, conda install -c conda-forge pint does run on my console, but it has actually not installed pint (which I had previously uninstalled), I don't really understand why...

As I said my solution was pip install Pint-0.8.1.tar.gz with Pint-0.8.1.tar.gz downloaded here.

[zbruick]

Pint functionality was fixed by #1087. Closing, but if there are still issues this can be reopened.