Abstracts elections-phragmen pallet to use NposSolver (#12588)

* Abstracts elections-phragmen pallet to use NposSolver

* Update frame/elections-phragmen/src/lib.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Update frame/elections-phragmen/src/lib.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* changes the name of the pallet; adds changelog

* update changelog

* Adds weight testing

* Adds log macro_rules

* renames elections-phragment dir to elections

* weights rename

* fixes typo in cargo toml

* pre/post solve weight scafolding

* refactor do_post_election

* refactors into pre and post election solve for independent benchmarking

* deconstructs PreElectionResults struct

* updates benchmarking pre and post election solve; mock weights

* Update frame/elections/src/lib.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Update frame/elections/src/lib.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* addresses PR comments

* adds pre_solve and post_sove weights

* Adds comments on election pallet id param name change

* ".git/.scripts/bench-bot.sh" pallet dev pallet_elections

* Finishes pre-post solve weights

* Update frame/elections/src/lib.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Update frame/elections/src/lib.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Addresses PR comments: no panic in on_init path; nits

* Fixes node build

* Implements approval voting to use as a `NposSolver` (#13367)

* Implements the approval voting methods in sp_npos_elections

* fmt

* remove unecessary file

* comment clarification

* re-run weights

* fix typo

* updates MaxVoters in tests for integrity_tests to pass

* Refactors election provider support benchmarks outside its own crate (#13431)

* Refactors election provider support benchmarks outside its own crate
---------

Co-authored-by: command-bot <>

---------

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>
Co-authored-by: parity-processbot <>
Co-authored-by: Ross Bulat <ross@parity.io>

substrate/primitives/npos-elections/src/lib.rs

@@ -25,6 +25,8 @@
 //! - [`balance`](balancing::balance): Implements the star balancing algorithm. This iterative
 //!   process can push a solution toward being more "balanced", which in turn can increase its
 //!   score.
+//! - [`approval_voting`](approval_voting::approval_voting): Implements an approval voting electoral
+//!   system where voters can back multiple candidates with the same stake.
 //!
 //! ### Terminology
 //!
@@ -90,6 +92,7 @@ mod mock;
 #[cfg(test)]
 mod tests;
 
+pub mod approval_voting;
 mod assignments;
 pub mod balancing;
 pub mod helpers;
@@ -100,6 +103,7 @@ pub mod pjr;
 pub mod reduce;
 pub mod traits;
 
+pub use approval_voting::*;
 pub use assignments::{Assignment, StakedAssignment};
 pub use balancing::*;
 pub use helpers::*;