Using a single Quantity when plotting errorbars

[geolta]

When creating a matplotlib plot with errorbars (ax.errorbar) it is possible to use a single value for all errors:

import numpy as np
from matplotlib import pyplot as plt

x = np.array([1, 2, 3])
y = np.array([3, 1.5, 1])

fig, ax = plt.subplots()
ax.errorbar(x, y, yerr=0.5)
plt.show()

But this seem not to work when using pint:

import numpy as np
import pint
from matplotlib import pyplot as plt

ureg = pint.UnitRegistry()
ureg.setup_matplotlib()

x = np.array([1, 2, 3]) * ureg.meter
y = np.array([3, 1.5, 1]) * ureg.second

fig, ax = plt.subplots()
ax.errorbar(x, y, yerr=ureg.Quantity(0.5, "second"))
plt.show()

This outputs

/home/user/.local/lib/python3.12/site-packages/matplotlib/axes/_axes.py:3638: UnitStrippedWarning: The unit of the quantity is stripped when downcasting to ndarray.
  x = np.asarray(x, dtype=object)
/home/user/.local/lib/python3.12/site-packages/matplotlib/axes/_axes.py:3640: UnitStrippedWarning: The unit of the quantity is stripped when downcasting to ndarray.
  y = np.asarray(y, dtype=object)

Is this a pint issue or a matplotlib issue?

Best regards!

[andrewgsavage]

it's a matplotlib one, np.asarray(x, dtype=object) removes units hence the error message

[geolta]

Ok thank you :)
I will open a matplotlib issue for that.