[Features] Add smoothness loss function

[MeowZheng]

Motivation

as tittle

Modification

• add mmflow/models/losses/smooth_loss.py

[codecov]

Codecov Report

Merging #97 (09e8fbd) into master (ab06947) will increase coverage by 0.00%.
The diff coverage is 94.73%.

@@           Coverage Diff           @@
##           master      #97   +/-   ##
=======================================
  Coverage   68.03%   68.03%           
=======================================
  Files          86       87    +1     
  Lines        4896     4934   +38     
  Branches      705      709    +4     
=======================================
+ Hits         3331     3357   +26     
- Misses       1457     1467   +10     
- Partials      108      110    +2     

Flag	Coverage Δ
unittests	68.03% <94.73%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mmflow/models/losses/smooth_loss.py	94.59% <94.59%> (ø)
mmflow/models/losses/__init__.py	100.00% <100.00%> (ø)
mmflow/datasets/pipelines/transforms.py	78.16% <0.00%> (-1.67%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ab06947...09e8fbd. Read the comment docs.