1package gates
  2
  3import (
  4	"fmt"
  5	"regexp"
  6	"strconv"
  7
  8	"github.com/consensys/gnark/frontend"
  9	gl "github.com/succinctlabs/gnark-plonky2-verifier/goldilocks"
 10)
 11
 12var reducingGateRegex = regexp.MustCompile("ReducingGate { num_coeffs: (?P<numCoeffs>[0-9]+) }")
 13
 14func deserializeReducingGate(parameters map[string]string) Gate {
 15	// Has the format "ReducingGate { num_coeffs: 33 }"
 16	numCoeffs, hasNumCoeffs := parameters["numCoeffs"]
 17	if !hasNumCoeffs {
 18		panic("Missing field num_coeffs in ReducingGate")
 19	}
 20
 21	numCoeffsInt, err := strconv.Atoi(numCoeffs)
 22	if err != nil {
 23		panic("Invalid num_coeffs field in ReducingGate")
 24	}
 25
 26	return NewReducingGate(uint64(numCoeffsInt))
 27}
 28
 29type ReducingGate struct {
 30	numCoeffs uint64
 31}
 32
 33const START_COEFFS_REDUCING_GATE = 3 * gl.D
 34
 35func NewReducingGate(numCoeffs uint64) *ReducingGate {
 36	return &ReducingGate{
 37		numCoeffs: numCoeffs,
 38	}
 39}
 40
 41func (g *ReducingGate) Id() string {
 42	return fmt.Sprintf("ReducingExtensionGate { num_ops: %d }", g.numCoeffs)
 43}
 44
 45func (g *ReducingGate) wiresOutput() Range {
 46	return Range{0, gl.D}
 47}
 48
 49func (g *ReducingGate) wiresAlpha() Range {
 50	return Range{gl.D, 2 * gl.D}
 51}
 52
 53func (g *ReducingGate) wiresOldAcc() Range {
 54	return Range{2 * gl.D, 3 * gl.D}
 55}
 56
 57func (g *ReducingGate) wiresCoeff() Range {
 58	return Range{START_COEFFS_REDUCING_GATE, START_COEFFS_REDUCING_GATE + g.numCoeffs}
 59}
 60
 61func (g *ReducingGate) startAccs() uint64 {
 62	return START_COEFFS_REDUCING_GATE + g.numCoeffs
 63}
 64
 65func (g *ReducingGate) wiresAccs(i uint64) Range {
 66	if i >= g.numCoeffs {
 67		panic("Accumulator index out of bounds")
 68	}
 69
 70	if i == g.numCoeffs-1 {
 71		return g.wiresOutput()
 72	}
 73
 74	return Range{g.startAccs() + gl.D*i, g.startAccs() + gl.D*(i+1)}
 75}
 76
 77func (g *ReducingGate) EvalUnfiltered(
 78	api frontend.API,
 79	glApi gl.Chip,
 80	vars EvaluationVars,
 81) []gl.QuadraticExtensionVariable {
 82	alpha := vars.GetLocalExtAlgebra(g.wiresAlpha())
 83	oldAcc := vars.GetLocalExtAlgebra(g.wiresOldAcc())
 84
 85	coeffs := []gl.QuadraticExtensionVariable{}
 86	coeffsRange := g.wiresCoeff()
 87	for i := coeffsRange.start; i < coeffsRange.end; i++ {
 88		coeffs = append(coeffs, vars.localWires[i])
 89	}
 90
 91	accs := []gl.QuadraticExtensionAlgebraVariable{}
 92	for i := uint64(0); i < g.numCoeffs; i++ {
 93		accs = append(accs, vars.GetLocalExtAlgebra(g.wiresAccs(i)))
 94	}
 95
 96	constraints := []gl.QuadraticExtensionVariable{}
 97	acc := oldAcc
 98	for i := uint64(0); i < g.numCoeffs; i++ {
 99		var coeff gl.QuadraticExtensionAlgebraVariable
100		for j := 0; j < gl.D; j++ {
101			coeff[j] = gl.ZeroExtension()
102		}
103		coeff[0] = coeffs[i]
104		tmp := glApi.MulExtensionAlgebra(acc, alpha)
105		tmp = glApi.AddExtensionAlgebra(tmp, coeff)
106		tmp = glApi.SubExtensionAlgebra(tmp, accs[i])
107		for j := 0; j < gl.D; j++ {
108			constraints = append(constraints, tmp[j])
109		}
110		acc = accs[i]
111	}
112
113	return constraints
114}