Fix latex printing of undefined functions raised to a power

[mohamedrezk122]

The used notation to print functions raised to a power is standardized across all types of functions, the recognized and not recognized ones. The undefined functions raised to power should be wrapped between parenthesis. Also, corresponding tests have been modified.

References to other Issues or PRs

Fixes #24596

Brief description of what is fixed or changed

The used notation to print functions raised to a power is standardized across
all types of functions, the recognized and not recognized ones. The undefined
functions raised to power should be wrapped between parenthesis.

So instead of func**2(x) it should be (func(x))**2
but for regular functions like trigonometric functions, they stay the same sin**2(x)

Before the patch

After the patch

Also, corresponding tests have been modified.

Other comments

Release Notes

• printing
  • Fixed a bug in latex printing for undefined functions raised to a power.

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• printing
  • Fixed a bug in latex printing for undefined functions raised to a power. (#26331 by @mohamedrezk122)

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The used notation to print functions raised to a power is standardized across all types of functions, the recognized and not recognized ones. The undefined functions raised to power should be wrapped between parenthesis. Also, corresponding tests have been modified.

<!-- 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
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Fixes  #24596

#### Brief description of what is fixed or changed
The used notation to print functions raised to a power is standardized across
all types of functions, the recognized and not recognized ones. The undefined
functions raised to power should be wrapped between parenthesis.

So instead of ``func**2(x)`` it should be  ``(func(x))**2``
but for regular functions like trigonometric functions, they stay the same ``sin**2(x)``

**Before the patch**
![image](https://github.com/sympy/sympy/assets/59314933/6475e571-2896-419b-b345-c00bc243fc13)

**After the patch**
![image](https://github.com/sympy/sympy/assets/59314933/863b8467-e180-48dd-b84c-7ec9a91b3689)

Also, corresponding tests have been modified.


#### Other comments
<!-- @asmeurer  The tests are modified,  the bot will raise errors.-->

#### Release Notes

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* solvers
  * Added a new solver for logarithmic equations.

* functions
  * Fixed a bug with log of integers. Formerly, `log(-x)` incorrectly gave `-log(x)`.

* physics.units
  * Corrected a semantical error in the conversion between volt and statvolt which
    reported the volt as being larger than the statvolt.

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<!-- BEGIN RELEASE NOTES -->
* printing
  * Fixed a bug in latex printing for undefined functions raised to a power.  

<!-- END RELEASE NOTES -->

[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)

| Change   | Before [a00718ba]    | After [14a6e27d]    |   Ratio | Benchmark (Parameter)                                                |
|----------|----------------------|---------------------|---------|----------------------------------------------------------------------|
| -        | 67.8±0.8ms           | 44.5±0.6ms          |    0.66 | integrate.TimeIntegrationRisch02.time_doit(10)                       |
| -        | 68.6±0.6ms           | 43.6±0.2ms          |    0.63 | integrate.TimeIntegrationRisch02.time_doit_risch(10)                 |
| +        | 18.3±0.2μs           | 30.4±0.2μs          |    1.67 | integrate.TimeIntegrationRisch03.time_doit(1)                        |
| -        | 5.35±0.03ms          | 2.86±0.01ms         |    0.53 | logic.LogicSuite.time_load_file                                      |
| -        | 74.6±0.2ms           | 29.3±0.07ms         |    0.39 | polys.TimeGCD_GaussInt.time_op(1, 'dense')                           |
| -        | 73.6±0.2ms           | 29.3±0.1ms          |    0.4  | polys.TimeGCD_GaussInt.time_op(1, 'sparse')                          |
| -        | 254±0.8ms            | 128±1ms             |    0.5  | polys.TimeGCD_GaussInt.time_op(2, 'dense')                           |
| -        | 257±2ms              | 128±0.6ms           |    0.5  | polys.TimeGCD_GaussInt.time_op(2, 'sparse')                          |
| -        | 657±7ms              | 374±1ms             |    0.57 | polys.TimeGCD_GaussInt.time_op(3, 'dense')                           |
| -        | 657±5ms              | 378±2ms             |    0.57 | polys.TimeGCD_GaussInt.time_op(3, 'sparse')                          |
| -        | 494±7μs              | 287±0.7μs           |    0.58 | polys.TimeGCD_LinearDenseQuadraticGCD.time_op(1, 'dense')            |
| -        | 1.80±0.02ms          | 1.07±0ms            |    0.59 | polys.TimeGCD_LinearDenseQuadraticGCD.time_op(2, 'dense')            |
| -        | 5.88±0.08ms          | 3.16±0.02ms         |    0.54 | polys.TimeGCD_LinearDenseQuadraticGCD.time_op(3, 'dense')            |
| -        | 453±2μs              | 229±2μs             |    0.51 | polys.TimeGCD_QuadraticNonMonicGCD.time_op(1, 'dense')               |
| -        | 1.48±0.01ms          | 673±2μs             |    0.45 | polys.TimeGCD_QuadraticNonMonicGCD.time_op(2, 'dense')               |
| -        | 4.98±0.02ms          | 1.64±0.01ms         |    0.33 | polys.TimeGCD_QuadraticNonMonicGCD.time_op(3, 'dense')               |
| -        | 387±2μs              | 205±1μs             |    0.53 | polys.TimeGCD_SparseGCDHighDegree.time_op(1, 'dense')                |
| -        | 2.44±0.01ms          | 1.25±0.01ms         |    0.51 | polys.TimeGCD_SparseGCDHighDegree.time_op(3, 'dense')                |
| -        | 9.99±0.04ms          | 4.49±0.03ms         |    0.45 | polys.TimeGCD_SparseGCDHighDegree.time_op(5, 'dense')                |
| -        | 358±1μs              | 168±0.7μs           |    0.47 | polys.TimeGCD_SparseNonMonicQuadratic.time_op(1, 'dense')            |
| -        | 2.47±0.01ms          | 919±20μs            |    0.37 | polys.TimeGCD_SparseNonMonicQuadratic.time_op(3, 'dense')            |
| -        | 9.60±0.07ms          | 2.69±0.01ms         |    0.28 | polys.TimeGCD_SparseNonMonicQuadratic.time_op(5, 'dense')            |
| -        | 1.05±0ms             | 430±3μs             |    0.41 | polys.TimePREM_LinearDenseQuadraticGCD.time_op(3, 'dense')           |
| -        | 1.72±0.01ms          | 505±3μs             |    0.29 | polys.TimePREM_LinearDenseQuadraticGCD.time_op(3, 'sparse')          |
| -        | 5.92±0.06ms          | 1.81±0.02ms         |    0.31 | polys.TimePREM_LinearDenseQuadraticGCD.time_op(5, 'dense')           |
| -        | 8.54±0.02ms          | 1.49±0.01ms         |    0.17 | polys.TimePREM_LinearDenseQuadraticGCD.time_op(5, 'sparse')          |
| -        | 287±1μs              | 64.8±0.5μs          |    0.23 | polys.TimePREM_QuadraticNonMonicGCD.time_op(1, 'sparse')             |
| -        | 3.47±0.04ms          | 406±9μs             |    0.12 | polys.TimePREM_QuadraticNonMonicGCD.time_op(3, 'dense')              |
| -        | 4.01±0.03ms          | 279±0.7μs           |    0.07 | polys.TimePREM_QuadraticNonMonicGCD.time_op(3, 'sparse')             |
| -        | 7.05±0.7ms           | 1.27±0.01ms         |    0.18 | polys.TimePREM_QuadraticNonMonicGCD.time_op(5, 'dense')              |
| -        | 8.73±0.07ms          | 838±5μs             |    0.1  | polys.TimePREM_QuadraticNonMonicGCD.time_op(5, 'sparse')             |
| -        | 5.05±0ms             | 2.99±0.01ms         |    0.59 | polys.TimeSUBRESULTANTS_LinearDenseQuadraticGCD.time_op(2, 'sparse') |
| -        | 12.2±0.1ms           | 6.65±0.04ms         |    0.54 | polys.TimeSUBRESULTANTS_LinearDenseQuadraticGCD.time_op(3, 'dense')  |
| -        | 22.5±0.1ms           | 9.06±0.05ms         |    0.4  | polys.TimeSUBRESULTANTS_LinearDenseQuadraticGCD.time_op(3, 'sparse') |
| -        | 5.27±0.01ms          | 875±4μs             |    0.17 | polys.TimeSUBRESULTANTS_QuadraticNonMonicGCD.time_op(1, 'sparse')    |
| -        | 12.6±0.05ms          | 7.04±0.02ms         |    0.56 | polys.TimeSUBRESULTANTS_QuadraticNonMonicGCD.time_op(2, 'sparse')    |
| -        | 103±0.4ms            | 26.3±0.1ms          |    0.26 | polys.TimeSUBRESULTANTS_QuadraticNonMonicGCD.time_op(3, 'dense')     |
| -        | 167±0.6ms            | 53.9±0.09ms         |    0.32 | polys.TimeSUBRESULTANTS_QuadraticNonMonicGCD.time_op(3, 'sparse')    |
| -        | 173±1μs              | 111±0.7μs           |    0.64 | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(1, 'dense')      |
| -        | 362±1μs              | 216±0.5μs           |    0.6  | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(1, 'sparse')     |
| -        | 4.24±0.04ms          | 849±10μs            |    0.2  | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(3, 'dense')      |
| -        | 5.37±0.03ms          | 385±5μs             |    0.07 | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(3, 'sparse')     |
| -        | 19.6±0.1ms           | 2.83±0.01ms         |    0.14 | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(5, 'dense')      |
| -        | 22.9±0.1ms           | 627±2μs             |    0.03 | polys.TimeSUBRESULTANTS_SparseGCDHighDegree.time_op(5, 'sparse')     |
| -        | 587±100μs            | 136±2μs             |    0.23 | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(1, 'sparse') |
| -        | 4.71±0.04ms          | 628±10μs            |    0.13 | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(3, 'dense')  |
| -        | 5.40±0.03ms          | 138±0.8μs           |    0.03 | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(3, 'sparse') |
| -        | 13.1±0.06ms          | 1.29±0.01ms         |    0.1  | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(5, 'dense')  |
| -        | 14.0±0.1ms           | 141±0.7μs           |    0.01 | polys.TimeSUBRESULTANTS_SparseNonMonicQuadratic.time_op(5, 'sparse') |
| -        | 134±1μs              | 74.8±0.5μs          |    0.56 | solve.TimeMatrixOperations.time_rref(3, 0)                           |
| -        | 254±2μs              | 87.6±0.4μs          |    0.35 | solve.TimeMatrixOperations.time_rref(4, 0)                           |
| -        | 24.2±0.1ms           | 10.0±0.03ms         |    0.41 | solve.TimeSolveLinSys189x49.time_solve_lin_sys                       |
| -        | 28.2±0.09ms          | 15.4±0.05ms         |    0.55 | solve.TimeSparseSystem.time_linsolve_Aaug(20)                        |
| -        | 54.8±0.2ms           | 24.9±0.08ms         |    0.45 | solve.TimeSparseSystem.time_linsolve_Aaug(30)                        |
| -        | 28.1±0.2ms           | 15.2±0.08ms         |    0.54 | solve.TimeSparseSystem.time_linsolve_Ab(20)                          |
| -        | 54.6±0.2ms           | 24.6±0.1ms          |    0.45 | solve.TimeSparseSystem.time_linsolve_Ab(30)                          |

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

[haru-44]

Is accepted_latex_functions an appropriate condition for this?

sympy/sympy/printing/latex.py

Lines 36 to 44 in 07da3ce

	# Hand-picked functions which can be used directly in both LaTeX and MathJax
	# Complete list at
	# https://docs.mathjax.org/en/latest/tex.html#supported-latex-commands
	# This variable only contains those functions which SymPy uses.
	accepted_latex_functions = ['arcsin', 'arccos', 'arctan', 'sin', 'cos', 'tan',
	'sinh', 'cosh', 'tanh', 'sqrt', 'ln', 'log', 'sec',
	'csc', 'cot', 'coth', 're', 'im', 'frac', 'root',
	'arg',
	]

[mohamedrezk122]

@haru-44 I don't understand what do you mean with this, can you elaborate more ?

[haru-44]

I understand that the functions in accepted_latex_functions are printed as $\sin^2(x)$, not $\sin(x)^2$. I have two points to make.

• Is it common to write not only sin and cos but also log and re this way? (This I simply don't know.)
• From reading the comments in accepted_latex_functions, this list should not be used to determine whether to print $\sin(x)^2$ or $\sin^2(x)$. I think we should have our own list of target functions.

[mohamedrezk122]

I guess that makes sense, I will try to fix it.

[sylee957]

Why does these changes while Chi does not? I just notice the problem of asymmetry here. I think that maybe only Function should be parenthesized as per design, not other pre defined SymPy functions

[mohamedrezk122]

@haru-44 pointed out that we should define a dictionary with some defined functions, not just the ones defined in accepted_latex_functions, to solve such issue.