Add float sanitization to xlim and ylim in plot

[sylee957]

References to other Issues or PRs

Fixes #15261

Brief description of what is fixed or changed

I found that the issue had been caused by sympy number types directly passed to matplotlib's backend, and getting checked by numpy's isfinite(), which cannot handle sympy's numbers.

Any sympy's constants, or sympified numbers passed into plot's xlim and ylim would repeat the issue in this context.

>>> from sympy import *
>>>
>>> x    = symbols('x')
>>> eqn  = sin(x)
>>> p    = plot(eqn,(x,-10,10), xlim=(-5, sympify('5')), ylim=(-1, 1))
TypeError: ufunc 'isfinite' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''

I think every sympy's numbers should be sanitized into python default float type, before passed into matplotlib backend.

And also, I had added is_real check and is_finite check, to make sure that float() can be safely applied to, and to implement numpy's isfinite() check in sympy's own way.

I think range parameter has implicit way of sanitizing sympy's types unlike xlim or ylim,
so that the method could possibly be a workaround for original poster.

Other comments

Release Notes

• plotting
  • Fixed xlim and ylim from plot() not properly handling sympy's number classes.

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• plotting
  • Fixed xlim and ylim from plot() not properly handling sympy's number classes. (#15265 by @sylee957)

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#### References to other Issues or PRs
<!-- If this pull request fixes an issue, write "Fixes #NNNN" in that exact
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Fixes #15261

#### Brief description of what is fixed or changed

I found that the issue had been caused by sympy number types directly passed to matplotlib's backend, and getting checked by numpy's `isfinite()`, which cannot handle sympy's numbers.

Any sympy's constants, or sympified numbers passed into plot's `xlim` and `ylim` would repeat the issue in this context.

```
>>> from sympy import *
>>>
>>> x    = symbols('x')
>>> eqn  = sin(x)
>>> p    = plot(eqn,(x,-10,10), xlim=(-5, sympify('5')), ylim=(-1, 1))
TypeError: ufunc 'isfinite' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''
```

I think every sympy's numbers should be sanitized into python default `float` type, before passed into matplotlib backend.

And also, I had added `is_real` check and `is_finite` check, to make sure that `float()` can be safely applied to, and to implement numpy's `isfinite()` check in sympy's own way.

I think `range` parameter has implicit way of sanitizing sympy's types unlike `xlim` or `ylim`,
so that the method could possibly be a workaround for original poster.

#### Other comments


#### Release Notes

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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
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<!-- BEGIN RELEASE NOTES -->
- plotting
  - Fixed `xlim` and `ylim` from `plot()` not properly handling sympy's number classes.
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

[smichr]

+1