Move Constants to Module Buffer & Tests Update

[denproc]

Closes #362 Closes #363

Proposed Changes

• Change storage of scale_weights for MS-SSIM and MS-GMSD;
• Update tests accordigly
• Fix gradient propagation issues when CUDA used.

[codecov[bot]]

Codecov Report

Merging #364 (af6b45f) into master (01e16b7) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #364   +/-   ##
=======================================
  Coverage   90.62%   90.63%           
=======================================
  Files          36       36           
  Lines        2869     2871    +2     
=======================================
+ Hits         2600     2602    +2     
  Misses        269      269           

Flag	Coverage Δ
unittests	90.63% <100.00%> (+<0.01%)	:arrow_up:

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

Impacted Files	Coverage Δ
piq/gmsd.py	100.00% <100.00%> (ø)
piq/ms_ssim.py	100.00% <100.00%> (ø)

[sonarcloud[bot]]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication