From 39584d20d79a0063664b3adbe386cfc2658cd22b Mon Sep 17 00:00:00 2001
From: YaoGalteland <yaojgalteland@yao.home>
Date: Mon, 11 Mar 2024 10:02:49 +0100
Subject: [PATCH] remove mux.md

---
 book/src/design/gadgets/multiplexer.md | 132 -------------------------
 1 file changed, 132 deletions(-)
 delete mode 100644 book/src/design/gadgets/multiplexer.md

diff --git a/book/src/design/gadgets/multiplexer.md b/book/src/design/gadgets/multiplexer.md
deleted file mode 100644
index 6b531d2ace..0000000000
--- a/book/src/design/gadgets/multiplexer.md
+++ /dev/null
@@ -1,132 +0,0 @@
-# Multiplexer
-
-Given a boolean flag $\textsf{choice}$, this gadget is used for selecting one of two values ($\textsf{left}$ and $\textsf{right}$) based on the boolean flag.
-If $\textsf{choice}$ is true, it returns $\textsf{right}$; otherwise, it returns $\textsf{left}$. This functionality is crucial for circuits that require conditional logic.
-We use a multiplexer to compute differently for ZEC or for non-ZEC assets in Orchard protocol.
-
-
-## Chip instructions
-
-mux is an instruction of the conditional swap gadget.
-
-```rust,ignore,no_run
-pub trait CondSwapInstructions<F: Field>: UtilitiesInstructions<F> {
-    /// Given an input `(choice, left, right)` where `choice` is a boolean flag,
-    /// returns `left` if `choice` is not set and `right` if `choice` is set.
-    fn mux(
-        &self,
-        layouter: &mut impl Layouter<F>,
-        choice: Self::Var,
-        left: Self::Var,
-        right: Self::Var,
-    ) -> Result<Self::Var, Error>;
-}
-```
-
-## Implement chip traits
-
-```rust,ignore,no_run
-impl<F: PrimeField> CondSwapInstructions<F> for CondSwapChip<F> {
-    fn mux(
-        &self,
-        layouter: &mut impl Layouter<F>,
-        choice: Self::Var,
-        left: Self::Var,
-        right: Self::Var,
-    ) -> Result<Self::Var, Error> {
-        let config = self.config();
-
-        layouter.assign_region(
-            || "mux",
-            |mut region| {
-                // Enable `q_swap` selector
-                config.q_swap.enable(&mut region, 0)?;
-
-                // Copy in `a` value
-                let left = left.copy_advice(|| "copy left", &mut region, config.a, 0)?;
-
-                // Copy in `b` value
-                let right = right.copy_advice(|| "copy right", &mut region, config.b, 0)?;
-
-                // Copy `choice` value
-                let choice = choice.copy_advice(|| "copy choice", &mut region, config.swap, 0)?;
-
-                let a_swapped = left
-                    .value()
-                    .zip(right.value())
-                    .zip(choice.value())
-                    .map(|((left, right), choice)| {
-                        if *choice == F::from(0_u64) {
-                            left
-                        } else {
-                            right
-                        }
-                    })
-                    .cloned();
-                let b_swapped = left
-                    .value()
-                    .zip(right.value())
-                    .zip(choice.value())
-                    .map(|((left, right), choice)| {
-                        if *choice == F::from(0_u64) {
-                            right
-                        } else {
-                            left
-                        }
-                    })
-                    .cloned();
-
-                region.assign_advice(|| "out b_swap", self.config.b_swapped, 0, || b_swapped)?;
-                region.assign_advice(|| "out a_swap", self.config.a_swapped, 0, || a_swapped)
-            },
-        )
-    }
-}
-```
-
-## Multiplexer (mux) logic on ECC Points
-
-The mux chip also extends its functionality to work with elliptic curve points, facilitating operations like conditional selections between points. 
-Based on a boolean flag $\textsf{choice}$, it selects between two given points $\textsf{left}$ and $\textsf{right}$. 
-If $\textsf{choice}$ is true, it returns the point $\textsf{right}$; otherwise, it returns the point $\textsf{left}$. 
-
-```rust,ignore,no_run
-impl CondSwapChip<pallas::Base> {
-    /// Given an input `(choice, left, right)` where `choice` is a boolean flag and `left` and `right` are `EccPoint`,
-    /// returns `left` if `choice` is not set and `right` if `choice` is set.
-    pub fn mux_on_points(
-        &self,
-        mut layouter: impl Layouter<pallas::Base>,
-        choice: &AssignedCell<pallas::Base, pallas::Base>,
-        left: &EccPoint,
-        right: &EccPoint,
-    ) -> Result<EccPoint, plonk::Error> {
-        let x_cell = self.mux(&mut layouter, choice.clone(), left.x(), right.x())?;
-        let y_cell = self.mux(&mut layouter, choice.clone(), left.y(), right.y())?;
-        Ok(EccPoint::from_coordinates_unchecked(
-            x_cell.into(),
-            y_cell.into(),
-        ))
-    }
-
-    /// Given an input `(choice, left, right)` where `choice` is a boolean flag and `left` and `right` are
-    /// `NonIdentityEccPoint`, returns `left` if `choice` is not set and `right` if `choice` is set.
-    pub fn mux_on_non_identity_points(
-        &self,
-        mut layouter: impl Layouter<pallas::Base>,
-        choice: &AssignedCell<pallas::Base, pallas::Base>,
-        left: &NonIdentityEccPoint,
-        right: &NonIdentityEccPoint,
-    ) -> Result<NonIdentityEccPoint, plonk::Error> {
-        let x_cell = self.mux(&mut layouter, choice.clone(), left.x(), right.x())?;
-        let y_cell = self.mux(&mut layouter, choice.clone(), left.y(), right.y())?;
-        Ok(NonIdentityEccPoint::from_coordinates_unchecked(
-            x_cell.into(),
-            y_cell.into(),
-        ))
-    }
-}
-```
-
-
-