FID/IS metrics for GANs, EMA handler and bug fixes

PyTorch-Ignite 0.4.6 - Release Notes

New Features

• Added start_lr option to FastaiLRFinder (#2111)
• Added Model's EMA handler (#2098, #2102)
• Improved SLURM support: added hostlist expansion without using scontrol (#2092)

Metrics

• Added Inception Score (#2053)
• Added FID metric (#2049, #2061, #2085, #2094, #2103)
  • Blog post "GAN Evaluation : the Frechet Inception Distance and Inception Score metrics" (https://pytorch-ignite.ai/posts/gan-evaluation-with-fid-and-is/)
• Improved DDP support for metrics (#2096, #2083)
• Improved MetricsLambda to work with reset/update/compute API (#2091)

Bug fixes

• Modified auto_dataloader to not wrap user provided DistributedSampler (#2119)
• Raise error in DistributedProxySampler when sampler is already a DistributedSampler (#2120)
• Improved LRFinder error message (#2127)
• Added py.typed for type checkers (#2095)

Housekeeping

• #2123, #2117, #2116, #2110, #2093, #2086

Acknowledgments

🎉 Thanks to our community and all our contributors for the issues, PRs and 🌟 ⭐️ 🌟 !
💯 We really appreciate your implication into the project (in alphabetical order):

@01-vyom, @KickItLikeShika, @gucifer, @sandylaker, @schuhschuh, @sdesrozis, @trsvchn, @vfdev-5, @ydcjeff