Is this a bug

[Ash]

Hello All,

Please see the code below. Is this a bug in simpy?

from sympy import *

a = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])

b = a

a.col_del(0)

print(a, b)

Expected answer: a = [ [2, 3]

                                   [5, 6]

                                   [8, 9]]

b = [ [1, 2, 3]

        [4, 5, 6]

        [7, 8, 9]]

Actual answer: a = [ [2, 3]

                              [5, 6]

                              [8, 9]]

b = [ [2, 3]

        [5, 6]

        [8, 9]]

Thanks

Ash

[Aaron Meurer]

The default Matrix class is mutable, which means that col_del modifies
a in-place. Since b points to the same matrix as a, it is also
modified in-place. See https://nedbatchelder.com/text/names.html.

It may be simpler to reason about an immutable matrix. Use
ImmutableMatrix instead of Matrix. In that case, a.col_del(0) will
return a new matrix and not modify a in-place.

Aaron Meurer

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[Ashith Shyam]

Thank you very much Aaron

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R.B. Ashith Shyam

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