sonobe-fs 0.1.0-alpha.1

Traits and implementations of folding schemes for the Sonobe library
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109

//! In-circuit variables for Nova witnesses.

use ark_r1cs_std::{
    GR1CSVar,
    alloc::{AllocVar, AllocationMode},
};
use ark_relations::gr1cs::{ConstraintSystemRef, Namespace, SynthesisError};
use ark_std::borrow::Borrow;
use sonobe_primitives::commitments::CommitmentDefGadget;

use super::{IncomingWitness, RunningWitness};

/// [`RunningWitnessVar`] defines Nova's running witness variable.
#[derive(Debug, PartialEq)]
pub struct RunningWitnessVar<CM: CommitmentDefGadget> {
    /// [`RunningWitnessVar::e`] is the error term.
    pub e: Vec<CM::ScalarVar>,
    /// [`RunningWitnessVar::r_e`] is the randomness for the error term
    /// commitment.
    pub r_e: CM::RandomnessVar,
    /// [`RunningWitnessVar::w`] is the vector of witnesses (to the circuit).
    pub w: Vec<CM::ScalarVar>,
    /// [`RunningWitnessVar::r_w`] is the randomness for the witness commitment.
    pub r_w: CM::RandomnessVar,
}

impl<CM: CommitmentDefGadget> AllocVar<RunningWitness<CM::Widget>, CM::ConstraintField>
    for RunningWitnessVar<CM>
{
    fn new_variable<T: Borrow<RunningWitness<CM::Widget>>>(
        cs: impl Into<Namespace<CM::ConstraintField>>,
        f: impl FnOnce() -> Result<T, SynthesisError>,
        mode: AllocationMode,
    ) -> Result<Self, SynthesisError> {
        let cs = cs.into().cs();
        let v = f()?;
        let RunningWitness { e, r_e, w, r_w } = v.borrow();
        Ok(Self {
            e: AllocVar::new_variable(cs.clone(), || Ok(&e[..]), mode)?,
            r_e: AllocVar::new_variable(cs.clone(), || Ok(r_e), mode)?,
            w: AllocVar::new_variable(cs.clone(), || Ok(&w[..]), mode)?,
            r_w: AllocVar::new_variable(cs.clone(), || Ok(r_w), mode)?,
        })
    }
}

impl<CM: CommitmentDefGadget> GR1CSVar<CM::ConstraintField> for RunningWitnessVar<CM> {
    type Value = RunningWitness<CM::Widget>;

    fn cs(&self) -> ConstraintSystemRef<CM::ConstraintField> {
        self.e
            .cs()
            .or(self.r_e.cs())
            .or(self.w.cs())
            .or(self.r_w.cs())
    }

    fn value(&self) -> Result<Self::Value, SynthesisError> {
        Ok(RunningWitness {
            e: self.e.value()?,
            r_e: self.r_e.value()?,
            w: self.w.value()?,
            r_w: self.r_w.value()?,
        })
    }
}

/// [`IncomingWitnessVar`] defines Nova's incoming witness variable.
#[derive(Debug, PartialEq)]
pub struct IncomingWitnessVar<CM: CommitmentDefGadget> {
    /// [`IncomingWitnessVar::w`] is the vector of witnesses (to the circuit).
    pub w: Vec<CM::ScalarVar>,
    /// [`IncomingWitnessVar::r_w`] is the randomness for the witness
    /// commitment.
    pub r_w: CM::RandomnessVar,
}

impl<CM: CommitmentDefGadget> AllocVar<IncomingWitness<CM::Widget>, CM::ConstraintField>
    for IncomingWitnessVar<CM>
{
    fn new_variable<T: Borrow<IncomingWitness<CM::Widget>>>(
        cs: impl Into<Namespace<CM::ConstraintField>>,
        f: impl FnOnce() -> Result<T, SynthesisError>,
        mode: AllocationMode,
    ) -> Result<Self, SynthesisError> {
        let cs = cs.into().cs();
        let v = f()?;
        let IncomingWitness { w, r_w } = v.borrow();
        Ok(Self {
            w: AllocVar::new_variable(cs.clone(), || Ok(&w[..]), mode)?,
            r_w: AllocVar::new_variable(cs.clone(), || Ok(r_w), mode)?,
        })
    }
}

impl<CM: CommitmentDefGadget> GR1CSVar<CM::ConstraintField> for IncomingWitnessVar<CM> {
    type Value = IncomingWitness<CM::Widget>;

    fn cs(&self) -> ConstraintSystemRef<CM::ConstraintField> {
        self.w.cs().or(self.r_w.cs())
    }

    fn value(&self) -> Result<Self::Value, SynthesisError> {
        Ok(IncomingWitness {
            w: self.w.value()?,
            r_w: self.r_w.value()?,
        })
    }
}