fix: fix #1149 by removing unused code (#1164)

* fix: fix #1149 by removing unused code

* fix: update stats without toNAF

internal/stats/snippet.go

@@ -70,12 +70,6 @@ func initSnippets() {
 	registerSnippet("math/bits.ToTernary/unconstrained", func(api frontend.API, newVariable func() frontend.Variable) {
 		_ = bits.ToTernary(api, newVariable(), bits.WithUnconstrainedOutputs())
 	})
-	registerSnippet("math/bits.ToNAF", func(api frontend.API, newVariable func() frontend.Variable) {
-		_ = bits.ToNAF(api, newVariable())
-	})
-	registerSnippet("math/bits.ToNAF/unconstrained", func(api frontend.API, newVariable func() frontend.Variable) {
-		_ = bits.ToNAF(api, newVariable(), bits.WithUnconstrainedOutputs())
-	})
 
 	registerSnippet("hash/mimc", func(api frontend.API, newVariable func() frontend.Variable) {
 		mimc, _ := mimc.NewMiMC(api)

std/math/bits/hints.go

@@ -1,7 +1,6 @@
 package bits
 
 import (
-	"errors"
 	"math/big"
 
 	"github.com/consensys/gnark/constraint/solver"
@@ -12,7 +11,6 @@ func GetHints() []solver.Hint {
 		ithBit,
 		nBits,
 		nTrits,
-		nNaf,
 	}
 }
 
@@ -61,54 +59,3 @@ func nTrits(_ *big.Int, inputs []*big.Int, results []*big.Int) error {
 
 	return nil
 }
-
-// NNAF returns the NAF decomposition of the input. The number of digits is
-// defined by the number of elements in the results slice.
-func nNaf(_ *big.Int, inputs []*big.Int, results []*big.Int) error {
-	n := inputs[0]
-	return nafDecomposition(n, results)
-}
-
-// nafDecomposition gets the naf decomposition of a big number
-func nafDecomposition(a *big.Int, results []*big.Int) error {
-	if a == nil || a.Sign() == -1 {
-		return errors.New("invalid input to naf decomposition; negative (or nil) big.Int not supported")
-	}
-
-	var zero, one, three big.Int
-
-	one.SetUint64(1)
-	three.SetUint64(3)
-
-	n := 0
-
-	// some buffers
-	var buf, aCopy big.Int
-	aCopy.Set(a)
-
-	for aCopy.Cmp(&zero) != 0 && n < len(results) {
-
-		// if aCopy % 2 == 0
-		buf.And(&aCopy, &one)
-
-		// aCopy even
-		if buf.Cmp(&zero) == 0 {
-			results[n].SetUint64(0)
-		} else { // aCopy odd
-			buf.And(&aCopy, &three)
-			if buf.IsUint64() && buf.Uint64() == 3 {
-				results[n].SetInt64(-1)
-				aCopy.Add(&aCopy, &one)
-			} else {
-				results[n].SetUint64(1)
-			}
-		}
-		aCopy.Rsh(&aCopy, 1)
-		n++
-	}
-	for ; n < len(results); n++ {
-		results[n].SetUint64(0)
-	}
-
-	return nil
-}