Add a warning in remesch_botsch if all vertices are detected as boundary vertices

[EmJay276]

If all vertices of a mesh are detected as boundary vertices, the remesh_botsch will return the input.
I've added a warning to make the user aware in this case (L65 - L67).

Additionally, I applied PEP8 style guide (whitespace) to the code.

[EmJay276]

Due to my last post in #68 (comment) I am not sure if this should be merged.

I need to check first if the following example would also result in the same output as the input was

A ------ B
| \      | 
|   \    | 
|     \  | 
C------- D

[EmJay276]

Minimal example for #69 (comment)

import gpytoolbox as gpy
import numpy as np

v = np.array(((0., 0., 0.),
              (10, 0., 0.),
              (0., 10, 0.),
              (10, 10, 0.)))

f = np.array(((0, 1, 3),
              (0, 2, 3)), dtype=np.int32)

u, g = gpy.remesh_botsch(v, f, h=1.)

print(f"Input: {v.shape = }, {f.shape = }")
print(f"Output: {u.shape = }, {g.shape = }")

Result

Input: v.shape = (4, 3), f.shape = (2, 3)
Output: u.shape = (4, 3), g.shape = (2, 3)

I would at least suggest to warn the user.
As user I would also expect the remesher should add vertices within the plane / at the edges.

[sgsellan]

This makes sense! Still, in L66, shouldn't we compare the length of V to the length of the unique entries of feature? Since feature is concatenating the user input and boundary vertices, its length could actually be larger than the size of V if, for example, I ran u, g = gpy.remesh_botsch(v, f, h=1.,feature=np.array([0],dtype=np.int32)) on your example above, which would not currently trigger the warning. Speaking off the cuff, free to tell me if I'm wrong!

[EmJay276]

Indeed! Fixed with 7bdcd09

[sgsellan]

Awesome! I'll merge after checks.

Also, what is this PEP8 style guide? Should we apply it across the whole library?

[EmJay276]

Also, what is this PEP8 style guide? Should we apply it across the whole library?

It's the Python Enhancement Proposals (PEP) for "Style Guide for Python Code"
https://peps.python.org/pep-0008/

PEP8 is mainly code formatting, which most Python IDEs automatically suggest. Including my IDE (PyCharm).

I'm my opinion it makes the code easier to read.

For example u = (0, 1 * 2) instead of u=(0,1*2)