mirror of
https://github.com/logos-storage/plonky2.git
synced 2026-01-09 01:03:08 +00:00
75 lines
2.7 KiB
Rust
75 lines
2.7 KiB
Rust
use crate::circuit_builder::CircuitBuilder;
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use crate::field::extension_field::Extendable;
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use crate::gates::base_sum::BaseSumGate;
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use crate::target::Target;
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impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
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/// Split the given element into a list of targets, where each one represents a
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/// base-B limb of the element, with little-endian ordering.
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pub(crate) fn split_le_base<const B: usize>(
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&mut self,
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x: Target,
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num_limbs: usize,
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) -> Vec<Target> {
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let gate = self.add_gate(BaseSumGate::<B>::new(num_limbs), vec![]);
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let sum = Target::wire(gate, BaseSumGate::<B>::WIRE_SUM);
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self.route(x, sum);
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Target::wires_from_range(
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gate,
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BaseSumGate::<B>::START_LIMBS..BaseSumGate::<B>::START_LIMBS + num_limbs,
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)
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}
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/// Asserts that `x`'s big-endian bit representation has at least `leading_zeros` leading zeros.
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pub(crate) fn assert_leading_zeros(&mut self, x: Target, leading_zeros: u32) {
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self.range_check(x, (64 - leading_zeros) as usize);
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}
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pub(crate) fn reverse_limbs<const B: usize>(&mut self, x: Target, num_limbs: usize) -> Target {
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let gate = self.add_gate(BaseSumGate::<B>::new(num_limbs), vec![]);
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let sum = Target::wire(gate, BaseSumGate::<B>::WIRE_SUM);
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self.route(x, sum);
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Target::wire(gate, BaseSumGate::<B>::WIRE_REVERSED_SUM)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use crate::circuit_data::CircuitConfig;
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use crate::field::crandall_field::CrandallField;
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use crate::field::field::Field;
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use crate::verifier::verify;
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use crate::witness::PartialWitness;
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#[test]
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fn test_split_base() {
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type F = CrandallField;
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let config = CircuitConfig::large_config();
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let mut builder = CircuitBuilder::<F, 4>::new(config);
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let x = F::from_canonical_usize(0b110100000); // 416 = 1532 in base 6.
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let xt = builder.constant(x);
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let limbs = builder.split_le_base::<6>(xt, 24);
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let one = builder.one();
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let two = builder.two();
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let three = builder.constant(F::from_canonical_u64(3));
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let five = builder.constant(F::from_canonical_u64(5));
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builder.route(limbs[0], two);
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builder.route(limbs[1], three);
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builder.route(limbs[2], five);
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builder.route(limbs[3], one);
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let rev = builder.constant(F::from_canonical_u64(11));
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let revt = builder.reverse_limbs::<2>(xt, 9);
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builder.route(revt, rev);
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builder.assert_leading_zeros(xt, 64 - 9);
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let data = builder.build();
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let proof = data.prove(PartialWitness::new());
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verify(proof, &data.verifier_only, &data.common).unwrap();
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}
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}
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