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 arithmeticGateRegex = regexp.MustCompile("ArithmeticGate { num_ops: (?P<numOps>[0-9]+) }")
13
14func deserializeArithmeticGate(parameters map[string]string) Gate {
15	// Has the format "ArithmeticGate { num_ops: 10 }"
16
17	numOps, hasNumOps := parameters["numOps"]
18	if !hasNumOps {
19		panic("no num_ops field in ArithmeticGate")
20	}
21
22	numOpsInt, err := strconv.Atoi(numOps)
23	if err != nil {
24		panic("Invalid num_ops field in ArithmeticGate")
25	}
26
27	return NewArithmeticGate(uint64(numOpsInt))
28}
29
30type ArithmeticGate struct {
31	numOps uint64
32}
33
34func NewArithmeticGate(numOps uint64) *ArithmeticGate {
35	return &ArithmeticGate{
36		numOps: numOps,
37	}
38}
39
40func (g *ArithmeticGate) Id() string {
41	return fmt.Sprintf("ArithmeticGate { num_ops: %d }", g.numOps)
42}
43
44func (g *ArithmeticGate) WireIthMultiplicand0(i uint64) uint64 {
45	return 4 * i
46}
47
48func (g *ArithmeticGate) WireIthMultiplicand1(i uint64) uint64 {
49	return 4*i + 1
50}
51
52func (g *ArithmeticGate) WireIthAddend(i uint64) uint64 {
53	return 4*i + 2
54}
55
56func (g *ArithmeticGate) WireIthOutput(i uint64) uint64 {
57	return 4*i + 3
58}
59
60func (g *ArithmeticGate) EvalUnfiltered(
61	api frontend.API,
62	glApi gl.Chip,
63	vars EvaluationVars,
64) []gl.QuadraticExtensionVariable {
65	const0 := vars.localConstants[0]
66	const1 := vars.localConstants[1]
67
68	constraints := []gl.QuadraticExtensionVariable{}
69	for i := uint64(0); i < g.numOps; i++ {
70		multiplicand0 := vars.localWires[g.WireIthMultiplicand0(i)]
71		multiplicand1 := vars.localWires[g.WireIthMultiplicand1(i)]
72		addend := vars.localWires[g.WireIthAddend(i)]
73		output := vars.localWires[g.WireIthOutput(i)]
74
75		computedOutput := glApi.AddExtension(
76			glApi.MulExtension(glApi.MulExtension(multiplicand0, multiplicand1), const0),
77			glApi.MulExtension(addend, const1),
78		)
79
80		constraints = append(constraints, glApi.SubExtension(output, computedOutput))
81	}
82
83	return constraints
84}