REF: Refactor ADAM to use full-adjoint

[carterbox]

Purpose

Save some computation in ADAM algorithm by using full adjoint and simultaneous updates

Approach

Pre-Merge Checklists

Submitter

• [ ] Write a helpfully descriptive pull request title.
• [ ] Organize changes into logically grouped commits with descriptive commit messages.
• [ ] Document all new functions.
• [ ] Write tests for new functions or explain why they are not needed.
• [ ] Build the documentation successfully
• [ ] Use yapf to format python code.

Reviewer

• [ ] Actually read all of the code.
• [ ] Run the new code yourself.
• [ ] Write a summary of the changes as you understand them.
• [ ] Thank the submitter.