Neuralsde

[JuanKo96]

Opening the first PR for NeuralSDE for integrating sdeint into torchdyn. Also, as I formatted code files I have made changes using black, we can use this format for future uses if everyone likes it.

The goal is to substitute sdeint module from torchsde into torchdyn native version. Will open different PRs for Brownian Interval and adjoint methods(+ other methods if possible).

• sdeint with fixed step size
• NeuralSDE module able to run training
• SDEFunc module for NeuralSDE
• jupyter notebook for NeuralSDE cookbook

[Zymrael]

LGTM overall.

Let's get some basic correctness tests in for sdeint before moving on to adaptive integration.

[codecov-commenter]

Codecov Report

Attention: 74 lines in your changes are missing coverage. Please review.

Comparison is base (c708c4c) 64.59% compared to head (0bbdd3e) 66.15%.

Files	Patch %	Lines
torchdyn/core/neuralde.py	54.90%	23 Missing ⚠️
torchdyn/core/problems.py	61.22%	19 Missing ⚠️
torchdyn/numerics/sdeint.py	78.12%	14 Missing ⚠️
torchdyn/core/defunc.py	70.45%	13 Missing ⚠️
torchdyn/numerics/solvers/sde.py	93.97%	5 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##           master     #166      +/-   ##
==========================================
+ Coverage   64.59%   66.15%   +1.55%     
==========================================
  Files          27       29       +2     
  Lines        1881     2074     +193     
==========================================
+ Hits         1215     1372     +157     
- Misses        666      702      +36     

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[JuanKo96]

This PR is ready to be merged.