tensor: fix printing of TensMul with imaginary coefficients

[Kishore96in]

References to other Issues or PRs

Fixes #24473

Brief description of what is fixed or changed

To find the sign of the coefficient, earlier the code would just compare it to zero, leading to an error for an imaginary coefficient. Now, it uses could_extract_minus_sign.

Other comments

After this PR:

>>> print(-I*K(p))
-I*K(p)
>>> print(I*K(p))
I*K(p)
>>> print(K(p))
K(p)
>>> print(-K(p))
-K(p)

Release Notes

• tensor
  • Fixed bug in printing TensMul.

[sympy-bot]

✅

Hi, I am the SymPy bot (v169). I'm here to help you write a release notes entry. Please read the guide on how to write release notes.

Your release notes are in good order.

Here is what the release notes will look like:

• tensor
  • Fixed bug in printing TensMul. (#24474 by @Kishore96in)

This will be added to https://github.com/sympy/sympy/wiki/Release-Notes-for-1.12.

Click here to see the pull request description that was parsed.

<!-- Your title above should be a short description of what
was changed. Do not include the issue number in the title. -->

#### References to other Issues or PRs
<!-- If this pull request fixes an issue, write "Fixes #NNNN" in that exact
format, e.g. "Fixes #1234" (see
https://tinyurl.com/auto-closing for more information). Also, please
write a comment on that issue linking back to this pull request once it is
open. -->

Fixes #24473


#### Brief description of what is fixed or changed
To find the sign of the coefficient, earlier the code would just compare it to zero, leading to an error for an imaginary coefficient. Now, it uses `could_extract_minus_sign`.

#### Other comments

After this PR:
```
>>> print(-I*K(p))
-I*K(p)
>>> print(I*K(p))
I*K(p)
>>> print(K(p))
K(p)
>>> print(-K(p))
-K(p)
```

#### Release Notes

<!-- Write the release notes for this release below between the BEGIN and END
statements. The basic format is a bulleted list with the name of the subpackage
and the release note for this PR. For example:

* solvers
  * Added a new solver for logarithmic equations.

* functions
  * Fixed a bug with log of integers.

or if no release note(s) should be included use:

NO ENTRY

See https://github.com/sympy/sympy/wiki/Writing-Release-Notes for more
information on how to write release notes. The bot will check your release
notes automatically to see if they are formatted correctly. -->

<!-- BEGIN RELEASE NOTES -->

* tensor
    * Fixed bug in printing TensMul.

<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

[github-actions]

Benchmark results from GitHub Actions

Lower numbers are good, higher numbers are bad. A ratio less than 1
means a speed up and greater than 1 means a slowdown. Green lines
beginning with + are slowdowns (the PR is slower then master or
master is slower than the previous release). Red lines beginning
with - are speedups.

Significantly changed benchmark results (PR vs master)

Significantly changed benchmark results (master vs previous release)

       before           after         ratio
     [41d90958]       [6f0fd470]
     <sympy-1.11.1^0>                 
-      1.30±0.1ms         844±10μs     0.65  solve.TimeSparseSystem.time_linear_eq_to_matrix(10)
-      3.62±0.1ms      1.51±0.03ms     0.42  solve.TimeSparseSystem.time_linear_eq_to_matrix(20)
-      6.89±0.4ms      2.25±0.03ms     0.33  solve.TimeSparseSystem.time_linear_eq_to_matrix(30)

Full benchmark results can be found as artifacts in GitHub Actions
(click on checks at the top of the PR).

[ThePauliPrinciple]

Could you add a test?

[sympy-bot]

🟠

Hi, I am the SymPy bot (v169). I've noticed that some of your commits add or delete files. Since this is sometimes done unintentionally, I wanted to alert you about it.

This is an experimental feature of SymPy Bot. If you have any feedback on it, please comment at sympy/sympy-bot#75.

The following commits add new files:

• b161676:
  • sympy/tensor/tests/test_printing.py

If these files were added/deleted on purpose, you can ignore this message.

[Kishore96in]

@ThePauliPrinciple I've added a test in sympy/tensor/tests/test_printing.py (new file).