Operating elementwise with numpy masked arrays about pint HOT 5 CLOSED

The new test case shows that the bug is because MaskedArray (and not Quantity) is handling the multiplication. When the order of the operation is reversed, everything works as expected.

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It looses the masked behaviour.

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Multiplying meter by a masked array works as expected:

>>> from pint import UnitRegistry
>>> ureg = UnitRegistry()
>>> import numpy as np
>>> x = np.ma.masked_array([1, 2, 3], mask=[True, True, False])
>>> q = ureg.meter * x
>>> q
<Quantity([-- -- 3], 'meter')>
>>> q.magnitude
masked_array(data = [-- -- 3],
             mask = [ True  True False],
       fill_value = 999999)

Is the converse that is not working properly:

>>> q = x * ureg.meter
>>> q
masked_array(data = [-- -- <Quantity(3, 'meter')>],
             mask = [ True  True False],
       fill_value = 999999)

Can you confirm this in your system?

The problem is that the multiplication is always handled by the left operand. I think that the bug is that the ufunc is not honoring of the array_priority value. I am trying to confirm this with the numpy people.

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Yes, I can confirm that it works with multiplication by left. thanks.

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Review once that #905 is implemented

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