Refac/arya todos

constraint/gkr.go

@@ -17,7 +17,7 @@ type InputDependency struct {
 }
 
 type GkrWire struct {
-	Gate            string // TODO: Change to description
+	GateName        string
 	Inputs          []int
 	Dependencies    []InputDependency // nil for input wires
 	NbUniqueOutputs int
@@ -49,7 +49,9 @@ func (w GkrWire) IsOutput() bool {
 	return w.NbUniqueOutputs == 0
 }
 
-// AssignmentOffsets returns the index of the first value assigned to a wire TODO: Explain clearly
+// AssignmentOffsets returns the index of the first value assigned to a wire in the Solve/Prove GKR hint.
+// For any GKR circuit wire, the explicitly assigned values (if any) across all instances are contiguous as hint inputs.
+// Thus, the indexes of all the assignments to the i'th wire are [d.AssignmentOffsets()[i], d.AssignmentOffsets()[i+1])
 func (d *GkrInfo) AssignmentOffsets() []int {
 	c := d.Circuit
 	res := make([]int, len(c)+1)
@@ -96,7 +98,7 @@ func (d *GkrInfo) Compile(nbInstances int) (GkrPermutations, error) {
 	p.SortedWires, uniqueOuts = algo_utils.TopologicalSort(inputs)
 	p.WiresPermutation = algo_utils.InvertPermutation(p.SortedWires)
 	wirePermutationAt := algo_utils.SliceAt(p.WiresPermutation)
-	sorted := make([]GkrWire, len(d.Circuit)) // TODO: Directly manipulate d.Circuit instead
+	sorted := make([]GkrWire, len(d.Circuit)) // perf-TODO: Directly manipulate d.Circuit instead
 	for newI, oldI := range p.SortedWires {
 		oldW := d.Circuit[oldI]
 
@@ -117,10 +119,10 @@ func (d *GkrInfo) Compile(nbInstances int) (GkrPermutations, error) {
 			if oldW.Dependencies[i].InputInstance == oldW.Dependencies[i-1].InputInstance {
 				return p, fmt.Errorf("an input wire can only have one dependency per instance")
 			}
-		} // TODO: Check that dependencies and explicit assignments cover all instances
+		}
 
 		sorted[newI] = GkrWire{
-			Gate:            oldW.Gate,
+			GateName:        oldW.GateName,
 			Inputs:          algo_utils.Map(oldW.Inputs, wirePermutationAt),
 			Dependencies:    oldW.Dependencies,
 			NbUniqueOutputs: len(uniqueOuts[oldI]),

internal/generator/backend/template/representations/gkr.go.tmpl

@@ -24,8 +24,8 @@ func convertCircuit(noPtr constraint.GkrCircuit) (gkr.Circuit, error) {
 	resCircuit := make(gkr.Circuit, len(noPtr))
 	var found bool
 	for i := range noPtr {
-		if resCircuit[i].Gate, found = gkr.Gates[noPtr[i].Gate]; !found && noPtr[i].Gate != "" {
-			return nil, fmt.Errorf("gate \"%s\" not found", noPtr[i].Gate)
+		if resCircuit[i].Gate, found = gkr.Gates[noPtr[i].GateName]; !found && noPtr[i].GateName != "" {
+			return nil, fmt.Errorf("gate \"%s\" not found", noPtr[i].GateName)
 		}
 		resCircuit[i].Inputs = algo_utils.Map(noPtr[i].Inputs, algo_utils.SlicePtrAt(resCircuit))
 	}

std/compress/io.go

@@ -1,7 +1,6 @@
 package compress
 
 import (
-	"errors"
 	"github.com/consensys/gnark/frontend"
 	"github.com/consensys/gnark/std/compress/internal/plonk"
 	"github.com/consensys/gnark/std/hash/mimc"
@@ -71,48 +70,6 @@ func ChecksumPaddedBytes(b []byte, validLength int, hsh hash.Hash, fieldNbBits i
 	return hsh.Sum(nil)
 }
 
-// UnpackIntoBytes construes every element in packed as consisting of bytesPerElem bytes, returning those bytes
-// it DOES NOT prove that the elements in unpacked are actually bytes
-// nbBytes is the number of "valid" bytes according to the padding scheme in https://github.com/Consensys/zkevm-monorepo/blob/main/prover/lib/compressor/blob/blob_maker.go#L299
-// TODO @tabaie @gbotrel move the padding/packing code to gnark or compress
-// the very last non-zero byte in the unpacked stream is meant to encode the number of unused bytes in the last field element used.
-// though UnpackIntoBytes includes that last byte in unpacked, it is not counted in nbBytes
-func UnpackIntoBytes(api frontend.API, bytesPerElem int, packed []frontend.Variable) (unpacked []frontend.Variable, nbBytes frontend.Variable, err error) {
-	if unpacked, err = api.Compiler().NewHint(UnpackIntoBytesHint, bytesPerElem*len(packed), packed...); err != nil {
-		return
-	}
-	found := frontend.Variable(0)
-	nbBytes = frontend.Variable(0)
-	for i := len(unpacked) - 1; i >= 0; i-- {
-
-		z := api.IsZero(unpacked[i])
-
-		lastNonZero := plonk.EvaluateExpression(api, z, found, -1, -1, 1, 1)   // nz - found
-		nbBytes = api.Add(nbBytes, api.Mul(lastNonZero, frontend.Variable(i))) // the last nonzero byte itself is useless
-
-		//api.AssertIsEqual(api.Mul(api.Sub(bytesPerElem-i%bytesPerElem, unpacked[i]), lastNonZero), 0) // sanity check, technically unnecessary TODO @Tabaie make sure it's one constraint only or better yet, remove
-
-		found = plonk.EvaluateExpression(api, z, found, -1, 0, 1, 1) // found ? 1 : nz = nz + found (1 - nz) = 1 - z + found z
-	}
-	return
-}
-
-func UnpackIntoBytesHint(_ *big.Int, ins, outs []*big.Int) error {
-	bytesPerElem := len(outs) / len(ins)
-	if len(ins)*bytesPerElem != len(outs) {
-		return errors.New("in length must divide out length")
-	}
-	_256 := big.NewInt(256)
-	var v big.Int
-	for i := range ins {
-		v.Set(ins[i])
-		for j := bytesPerElem - 1; j >= 0; j-- {
-			v.DivMod(&v, _256, outs[i*bytesPerElem+j])
-		}
-	}
-	return nil
-}
-
 // ReadNum reads the slice c as a big endian number in base radix
 func ReadNum(api frontend.API, c []frontend.Variable, radix *big.Int) frontend.Variable {
 	if len(c) == 0 {
@@ -177,7 +134,7 @@ func NewNumReader(api frontend.API, toRead []frontend.Variable, numNbBits, wordN
 }
 
 func (nr *NumReader) SetNumNbBits(numNbBits int) {
-	wordNbBits := nr.radix.BitLen() - 1 // TODO check
+	wordNbBits := nr.radix.BitLen() - 1
 	wordsPerNum := numNbBits / wordNbBits
 	if wordsPerNum*wordNbBits != numNbBits {
 		panic("numNbBits must be divisible by wordNbBits")

std/compress/lzss/snark.go

@@ -182,7 +182,6 @@ func RegisterHints() {
 	hint.RegisterHint(internal.BreakUpBytesIntoBitsHint)
 	hint.RegisterHint(internal.BreakUpBytesIntoCrumbsHint)
 	hint.RegisterHint(internal.BreakUpBytesIntoHalfHint)
-	hint.RegisterHint(compress.UnpackIntoBytesHint)
 }
 
 // options and other auxiliary input

std/gkr/api.go

@@ -11,8 +11,8 @@ func frontendVarToInt(a constraint.GkrVariable) int {
 
 func (api *API) NamedGate(gate string, in ...constraint.GkrVariable) constraint.GkrVariable {
 	api.toStore.Circuit = append(api.toStore.Circuit, constraint.GkrWire{
-		Gate:   gate,
-		Inputs: algo_utils.Map(in, frontendVarToInt),
+		GateName: gate,
+		Inputs:   algo_utils.Map(in, frontendVarToInt),
 	})
 	api.assignments = append(api.assignments, nil)
 	return constraint.GkrVariable(len(api.toStore.Circuit) - 1)

std/gkr/api_test.go

@@ -349,8 +349,8 @@ func (c *benchMiMCMerkleTreeCircuit) Define(api frontend.API) error {
 
 	// cheat{
 	gkr.toStore.Circuit = append(gkr.toStore.Circuit, constraint.GkrWire{
-		Gate:   "mimc",
-		Inputs: []int{int(x), int(y)},
+		GateName: "mimc",
+		Inputs:   []int{int(x), int(y)},
 	})
 	gkr.assignments = append(gkr.assignments, nil)
 	z := constraint.GkrVariable(2)
@@ -583,8 +583,8 @@ func (c *mimcNoDepCircuit) Define(api frontend.API) error {
 	z = y
 	for i := 0; i < c.mimcDepth; i++ {
 		_gkr.toStore.Circuit = append(_gkr.toStore.Circuit, constraint.GkrWire{
-			Gate:   "mimc",
-			Inputs: []int{int(x), int(z)},
+			GateName: "mimc",
+			Inputs:   []int{int(x), int(z)},
 		})
 		_gkr.assignments = append(_gkr.assignments, nil)
 		z = constraint.GkrVariable(len(_gkr.toStore.Circuit) - 1)

std/gkr/compile.go

@@ -230,7 +230,7 @@ func newCircuitDataForSnark(info constraint.GkrInfo, assignment assignment) circ
 	for i := range circuit {
 		w := info.Circuit[i]
 		circuit[i] = Wire{
-			Gate:            ite(w.IsInput(), Gates[w.Gate], Gate(IdentityGate{})),
+			Gate:            ite(w.IsInput(), Gates[w.GateName], Gate(IdentityGate{})),
 			Inputs:          algo_utils.Map(w.Inputs, circuitAt),
 			nbUniqueOutputs: w.NbUniqueOutputs,
 		}