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
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167

// Copyright (C) 2019-2023 Aleo Systems Inc.
// This file is part of the snarkVM library.

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at:
// http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use crate::snark::marlin::{
    ahp::{indexer::Circuit, AHPError, AHPForR1CS},
    prover,
    MarlinMode,
};
use snarkvm_fields::PrimeField;
use snarkvm_r1cs::ConstraintSynthesizer;
use std::collections::BTreeMap;

use snarkvm_utilities::cfg_iter;
#[cfg(not(feature = "std"))]
use snarkvm_utilities::println;

#[cfg(not(feature = "serial"))]
use rayon::prelude::*;

mod first;
mod fourth;
mod second;
mod third;

impl<F: PrimeField, MM: MarlinMode> AHPForR1CS<F, MM> {
    /// Initialize the AHP prover.
    pub fn init_prover<'a, C: ConstraintSynthesizer<F>>(
        circuits_to_constraints: &BTreeMap<&'a Circuit<F, MM>, &[C]>,
    ) -> Result<prover::State<'a, F, MM>, AHPError> {
        let init_time = start_timer!(|| "AHP::Prover::Init");

        let indices_and_assignments = cfg_iter!(circuits_to_constraints)
            .map(|(circuit, constraints)| {
                let num_non_zero_a = circuit.index_info.num_non_zero_a;
                let num_non_zero_b = circuit.index_info.num_non_zero_b;
                let num_non_zero_c = circuit.index_info.num_non_zero_c;

                let assignments = cfg_iter!(constraints)
                    .enumerate()
                    .map(|(_i, instance)| {
                        let constraint_time = start_timer!(|| format!(
                            "Generating constraints and witnesses for {:?} and index {_i}",
                            circuit.id
                        ));
                        let mut pcs = prover::ConstraintSystem::new();
                        instance.generate_constraints(&mut pcs)?;
                        end_timer!(constraint_time);

                        let padding_time = start_timer!(|| format!(
                            "Padding matrices to make them square for {:?} and index {_i}",
                            circuit.id
                        ));
                        crate::snark::marlin::ahp::matrices::pad_input_for_indexer_and_prover(&mut pcs);
                        pcs.make_matrices_square();
                        end_timer!(padding_time);

                        let prover::ConstraintSystem {
                            public_variables: padded_public_variables,
                            private_variables,
                            num_constraints,
                            num_public_variables,
                            num_private_variables,
                            ..
                        } = pcs;

                        assert_eq!(padded_public_variables.len(), num_public_variables);
                        assert!(padded_public_variables[0].is_one());
                        assert_eq!(private_variables.len(), num_private_variables);

                        if cfg!(debug_assertions) {
                            println!("Number of padded public variables in Prover::Init: {num_public_variables}");
                            println!("Number of private variables: {num_private_variables}");
                            println!("Number of constraints: {num_constraints}");
                            println!("Number of non-zero entries in A: {num_non_zero_a}");
                            println!("Number of non-zero entries in B: {num_non_zero_b}");
                            println!("Number of non-zero entries in C: {num_non_zero_c}");
                        }

                        if circuit.index_info.num_constraints != num_constraints
                            || circuit.index_info.num_variables != (num_public_variables + num_private_variables)
                        {
                            return Err(AHPError::InstanceDoesNotMatchIndex);
                        }

                        Self::formatted_public_input_is_admissible(&padded_public_variables)?;

                        let eval_z_a_time = start_timer!(|| format!("For {:?}, evaluating z_A_{_i}", circuit.id));
                        let z_a = cfg_iter!(circuit.a)
                            .map(|row| {
                                inner_product(&padded_public_variables, &private_variables, row, num_public_variables)
                            })
                            .collect();
                        end_timer!(eval_z_a_time);

                        let eval_z_b_time = start_timer!(|| format!("For {:?}, evaluating z_B_{_i}", circuit.id));
                        let z_b = cfg_iter!(circuit.b)
                            .map(|row| {
                                inner_product(&padded_public_variables, &private_variables, row, num_public_variables)
                            })
                            .collect();
                        end_timer!(eval_z_b_time);
                        end_timer!(init_time);
                        Ok(prover::Assignments::<F>(padded_public_variables, private_variables, z_a, z_b))
                    })
                    .collect::<Result<Vec<prover::Assignments<F>>, AHPError>>()?;
                Ok((*circuit, assignments))
            })
            .collect::<Result<BTreeMap<&'a Circuit<F, MM>, Vec<prover::Assignments<F>>>, AHPError>>()?;

        let state = prover::State::initialize(indices_and_assignments)?;

        Ok(state)
    }
}

fn inner_product<F: PrimeField>(
    public_variables: &[F],
    private_variables: &[F],
    row: &[(F, usize)],
    num_public_variables: usize,
) -> F {
    let mut result = F::zero();

    for &(ref coefficient, i) in row {
        // Fetch the variable.
        let variable = match i < num_public_variables {
            true => public_variables[i],
            false => private_variables[i - num_public_variables],
        };

        result += if coefficient.is_one() { variable } else { variable * coefficient };
    }

    result
}

#[test]
fn check_division_by_vanishing_poly_preserve_sparseness() {
    use crate::fft::{EvaluationDomain, Evaluations as EvaluationsOnDomain};
    use snarkvm_curves::bls12_377::Fr;
    use snarkvm_fields::{Field, One, Zero};

    let domain = EvaluationDomain::new(16).unwrap();
    let small_domain = EvaluationDomain::new(4).unwrap();
    let val = Fr::one().double().double().double() - Fr::one();
    let mut evals = (0..16).map(|pow| val.pow([pow])).collect::<Vec<_>>();
    for i in 0..4 {
        evals[4 * i] = Fr::zero();
    }
    let p = EvaluationsOnDomain::from_vec_and_domain(evals, domain).interpolate();
    assert_eq!(p.degree(), 15);
    let (p_div_v, p_mod_v) = p.divide_by_vanishing_poly(small_domain).unwrap();
    assert!(p_mod_v.is_zero());
    dbg!(p_div_v.degree());
    dbg!(p_div_v.evaluate_over_domain(domain));
}