Added guide for CycleGAN

[mayank2]

<insert pull request description here>

---

Checklist

Please go through each entry in the below checklist and mark an 'X' if that condition has been met. Every entry should be marked with an 'X' to be get the Pull Request approved.

• All imports are in the first cell? First block of imports are standard libraries, second block are 3rd party libraries, third block are all arcgis imports? Note that in some cases, for samples, it is a good idea to keep the imports next to where they are used, particularly for uncommonly used features that we want to highlight.
• All GIS object instantiations are one of the following?
  • gis = GIS()
  • gis = GIS('https://www.arcgis.com', 'arcgis_python', 'P@ssword123')
  • gis = GIS(profile="your_online_profile")
  • gis = GIS('https://pythonapi.playground.esri.com/portal', 'arcgis_python', 'amazing_arcgis_123')
  • gis = GIS(profile="your_enterprise_portal")
• If this notebook requires setup or teardown, did you add the appropriate code to ./misc/setup.py and/or ./misc/teardown.py?
• If this notebook references any portal items that need to be staged on AGOL/Python API playground, did you coordinate with a Python API team member to stage the item the correct way with the api_data_owner user?
• Code refactored & split out across multiple cells, useful comments?
• Consistent voice/tense/narrative style? Thoroughly checked for typos?
• All images used like <img src="base64str_here"> instead of <img src="https://some.url">? All map widgets contain a static image preview? (Call mapview_inst.take_screenshot() to do so)
• All file paths are constructed in an OS-agnostic fashion with os.path.join()? (Instead of r"\foo\bar", os.path.join(os.path.sep, "foo", "bar"), etc.)
• IF YOU WANT THIS SAMPLE TO BE DISPLAYED ON THE DEVELOPERS.ARCGIS.COM WEBSITE, ping @ DavidJVitale so he can add it to the list for the next deploy

[review-notebook-app]

Check out this pull request on 

See visual diffs & provide feedback on Jupyter Notebooks.

---

Powered by ReviewNB

[priyankatuteja]

@sdash77 Please do the first round of reviews.

[sdash77]

"In arcgis.learn, all the discriminators and generators have been grouped into a single model" Please remove this, it is the inherent architecture of cyclegan. Its grouped everywhere.

Describe a little about the objective function or loss that we get combining the three losses discussed above. feels incomplete.

Reply via ReviewNB

[sdash77]

looks fine to me @mayank2 Thanks.

[sdash77]

Seems fine to me.

[AtmaMani]

Change filename to 'how_cyclegan_works.ipynb' (no spaces, all lowercase)

Reply via ReviewNB

[AtmaMani]

"There are some challenges in Pix2Pix is that the images should be paired which are randomly organized or unpaired and we want to convert images from one domain to another just like " -> this sentence seems incomplete. Further, can you elaborate or reword the limitations of Pix2Pix model?

I think we also need to elaborate what you mean by an unpaired dataset

Reply via ReviewNB

[mayank2]

Yes, the sentence is incomplete. Thanks for pointing it out .

[AtmaMani]

Changes requested via reviewnb