tasm_lib/hashing/algebraic_hasher/
sample_scalars_static_length_static_pointer.rs

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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
use triton_vm::prelude::*;
use triton_vm::twenty_first::math::tip5::RATE;
use triton_vm::twenty_first::math::x_field_element::EXTENSION_DEGREE;

use crate::data_type::DataType;
use crate::hashing::algebraic_hasher::sample_scalars_static_length_dyn_malloc::SampleScalarsStaticLengthDynMalloc;
use crate::hashing::squeeze_repeatedly_static_number::SqueezeRepeatedlyStaticNumber;
use crate::library::Library;
use crate::traits::basic_snippet::BasicSnippet;

/// Squeeze the sponge to sample a given number of [`XFieldElement`]s. Puts the scalars into
/// statically allocated memory.
///
/// # Panics
///
/// Panics if both fields are 0 because the static allocator will be unhappy. :)
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
pub struct SampleScalarsStaticLengthStaticPointer {
    pub num_elements_to_sample: usize,

    /// Number of additional elements to statically allocate, in number of
    /// [extension field element][xfe]s.
    /// Necessary for [`Challenges`][chall].
    ///
    /// [chall]: crate::verifier::challenges::new_empty_input_and_output::NewEmptyInputAndOutput
    /// [xfe]: XFieldElement
    pub extra_capacity: usize,

    /// Memory address to store the scalars
    pub scalars_pointer: BFieldElement,
}

impl BasicSnippet for SampleScalarsStaticLengthStaticPointer {
    fn inputs(&self) -> Vec<(DataType, String)> {
        vec![]
    }

    fn outputs(&self) -> Vec<(DataType, String)> {
        vec![]
    }

    fn entrypoint(&self) -> String {
        format!(
            "tasmlib_hashing_algebraic_hasher_sample_scalars_static_length_static_pointer_{}_{}",
            self.num_elements_to_sample, self.scalars_pointer
        )
    }

    fn code(&self, library: &mut Library) -> Vec<LabelledInstruction> {
        assert_eq!(10, tip5::RATE, "Code assumes Tip5's RATE is 10");
        assert_eq!(3, EXTENSION_DEGREE, "Code assumes extension degree 3");
        let num_squeezes =
            SampleScalarsStaticLengthDynMalloc::num_squeezes(self.num_elements_to_sample);

        let num_squeezed_words = num_squeezes * RATE;
        debug_assert!(
            self.num_elements_to_sample * EXTENSION_DEGREE <= num_squeezed_words,
            "need {} elements but getting {num_squeezed_words}",
            self.num_elements_to_sample * EXTENSION_DEGREE,
        );

        let entrypoint = self.entrypoint();
        let squeeze_repeatedly_static_number =
            library.import(Box::new(SqueezeRepeatedlyStaticNumber { num_squeezes }));

        triton_asm!(
            {entrypoint}:
                push {self.scalars_pointer}
                call {squeeze_repeatedly_static_number}
                return
        )
    }
}

#[cfg(test)]
pub(crate) mod tests {
    use itertools::Itertools;
    use proptest_arbitrary_interop::arb;
    use rand::prelude::*;
    use test_strategy::proptest;
    use triton_vm::prelude::*;
    use triton_vm::twenty_first::util_types::algebraic_hasher::AlgebraicHasher;
    use triton_vm::twenty_first::util_types::algebraic_hasher::Sponge;

    use super::*;
    use crate::rust_shadowing_helper_functions::array::array_get;
    use crate::rust_shadowing_helper_functions::array::insert_as_array;
    use crate::test_helpers::tasm_final_state;
    use crate::traits::procedure::Procedure;
    use crate::traits::procedure::ProcedureInitialState;
    use crate::traits::procedure::ShadowedProcedure;
    use crate::traits::rust_shadow::RustShadow;
    use crate::VmHasher;

    impl Procedure for SampleScalarsStaticLengthStaticPointer {
        fn rust_shadow(
            &self,
            _stack: &mut Vec<BFieldElement>,
            memory: &mut std::collections::HashMap<BFieldElement, BFieldElement>,
            _nondeterminism: &NonDeterminism,
            _public_input: &[BFieldElement],
            sponge: &mut Option<VmHasher>,
        ) -> Vec<BFieldElement> {
            let sponge = sponge.as_mut().expect("sponge must be initialized");
            let num_squeezes =
                SampleScalarsStaticLengthDynMalloc::num_squeezes(self.num_elements_to_sample);
            let pseudorandomness = (0..num_squeezes)
                .flat_map(|_| sponge.squeeze().to_vec())
                .collect_vec();
            let scalars_pointer = self.scalars_pointer;
            insert_as_array(scalars_pointer, memory, pseudorandomness);

            vec![]
        }

        fn pseudorandom_initial_state(
            &self,
            seed: [u8; 32],
            _bench_case: Option<crate::snippet_bencher::BenchmarkCase>,
        ) -> ProcedureInitialState {
            let mut rng: StdRng = SeedableRng::from_seed(seed);
            let stack = self.init_stack_for_isolated_run();
            let sponge = Tip5 { state: rng.gen() };

            ProcedureInitialState {
                stack,
                sponge: Some(sponge),
                ..Default::default()
            }
        }

        fn corner_case_initial_states(&self) -> Vec<ProcedureInitialState> {
            let freshly_initialized_sponge = ProcedureInitialState {
                stack: self.init_stack_for_isolated_run(),
                sponge: Some(Tip5::init()),
                ..Default::default()
            };

            vec![freshly_initialized_sponge]
        }
    }

    #[test]
    fn sample_scalars_static_length_pbt() {
        for num_elements_to_sample in 0..11 {
            for extra_capacity in 0..11 {
                let scalars_pointer: BFieldElement = random();
                if num_elements_to_sample + extra_capacity == 0 {
                    continue;
                }
                ShadowedProcedure::new(SampleScalarsStaticLengthStaticPointer {
                    num_elements_to_sample,
                    extra_capacity,
                    scalars_pointer,
                })
                .test();
            }
        }
    }

    #[proptest]
    fn verify_agreement_with_tip5_sample_scalars(
        #[strategy(0_usize..500)] num_elements_to_sample: usize,
        #[strategy(0_usize..500)] extra_capacity: usize,
        #[strategy(arb())] scalars_pointer: BFieldElement,
        #[strategy(arb())] mut sponge: Tip5,
    ) {
        let snippet = SampleScalarsStaticLengthStaticPointer {
            num_elements_to_sample,
            extra_capacity,
            scalars_pointer,
        };
        let init_stack = snippet.init_stack_for_isolated_run();
        let tasm = tasm_final_state(
            &ShadowedProcedure::new(snippet),
            &init_stack,
            &[],
            NonDeterminism::default(),
            &Some(sponge.clone()),
        );

        let scalar_pointer = snippet.scalars_pointer;
        let read_scalar = |i| array_get(scalar_pointer, i, &tasm.ram, EXTENSION_DEGREE);

        let scalars_from_tip5 = sponge.sample_scalars(num_elements_to_sample);
        for (i, expected_scalar) in scalars_from_tip5.into_iter().enumerate() {
            assert_eq!(expected_scalar.coefficients.to_vec(), read_scalar(i));
        }
    }
}

#[cfg(test)]
mod bench {
    use super::*;
    use crate::traits::procedure::ShadowedProcedure;
    use crate::traits::rust_shadow::RustShadow;
    use crate::verifier::challenges::shared::conventional_challenges_pointer;

    #[test]
    fn bench_10() {
        ShadowedProcedure::new(SampleScalarsStaticLengthStaticPointer {
            num_elements_to_sample: 10,
            extra_capacity: 4,
            scalars_pointer: conventional_challenges_pointer(),
        })
        .bench();
    }

    #[test]
    fn bench_100() {
        ShadowedProcedure::new(SampleScalarsStaticLengthStaticPointer {
            num_elements_to_sample: 100,
            extra_capacity: 4,
            scalars_pointer: conventional_challenges_pointer(),
        })
        .bench();
    }

    #[test]
    fn bench_63() {
        ShadowedProcedure::new(SampleScalarsStaticLengthStaticPointer {
            num_elements_to_sample: 63,
            extra_capacity: 4,
            scalars_pointer: conventional_challenges_pointer(),
        })
        .bench();
    }
}