snarkvm-circuit-types-field 0.9.11

// Copyright (C) 2019-2022 Aleo Systems Inc.
// This file is part of the snarkVM library.

// The snarkVM library is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// The snarkVM library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with the snarkVM library. If not, see <https://www.gnu.org/licenses/>.

use super::*;

impl<E: Environment> Sub<Field<E>> for Field<E> {
    type Output = Self;

    fn sub(self, other: Field<E>) -> Self::Output {
        self - &other
    }
}

impl<E: Environment> Sub<&Field<E>> for Field<E> {
    type Output = Self;

    fn sub(self, other: &Field<E>) -> Self::Output {
        let mut result = self;
        result -= other;
        result
    }
}

impl<E: Environment> Sub<Field<E>> for &Field<E> {
    type Output = Field<E>;

    fn sub(self, other: Field<E>) -> Self::Output {
        self - &other
    }
}

impl<E: Environment> Sub<&Field<E>> for &Field<E> {
    type Output = Field<E>;

    fn sub(self, other: &Field<E>) -> Self::Output {
        let mut result = self.clone();
        result -= other;
        result
    }
}

impl<E: Environment> SubAssign<Field<E>> for Field<E> {
    fn sub_assign(&mut self, other: Field<E>) {
        *self -= &other;
    }
}

impl<E: Environment> SubAssign<&Field<E>> for Field<E> {
    fn sub_assign(&mut self, other: &Field<E>) {
        *self += -other;
    }
}

impl<E: Environment> Metrics<dyn Sub<Field<E>, Output = Field<E>>> for Field<E> {
    type Case = (Mode, Mode);

    fn count(_case: &Self::Case) -> Count {
        Count::is(0, 0, 0, 0)
    }
}

impl<E: Environment> OutputMode<dyn Sub<Field<E>, Output = Field<E>>> for Field<E> {
    type Case = (CircuitType<Field<E>>, CircuitType<Field<E>>);

    fn output_mode(case: &Self::Case) -> Mode {
        match (case.0.mode(), case.1.mode()) {
            (Mode::Constant, Mode::Constant) => Mode::Constant,
            (Mode::Public, Mode::Constant) => match &case.1 {
                CircuitType::Constant(constant) => match constant.eject_value().is_zero() {
                    true => Mode::Public,
                    false => Mode::Private,
                },
                _ => E::halt("The constant is required to determine the output mode of Public + Constant"),
            },
            (_, _) => Mode::Private,
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use snarkvm_circuit_environment::Circuit;

    const ITERATIONS: u64 = 10_000;

    fn check_sub(
        name: &str,
        expected: &console::Field<<Circuit as Environment>::Network>,
        a: &Field<Circuit>,
        b: &Field<Circuit>,
    ) {
        Circuit::scope(name, || {
            let candidate = a - b;
            assert_eq!(*expected, candidate.eject_value(), "({} - {})", a.eject_value(), b.eject_value());
            assert_count!(Sub(Field, Field) => Field, &(a.eject_mode(), b.eject_mode()));
            assert_output_mode!(Sub(Field, Field) => Field, &(CircuitType::from(a), CircuitType::from(b)), candidate);
        });
    }

    fn check_sub_assign(
        name: &str,
        expected: &console::Field<<Circuit as Environment>::Network>,
        a: &Field<Circuit>,
        b: &Field<Circuit>,
    ) {
        Circuit::scope(name, || {
            let mut candidate = a.clone();
            candidate -= b;
            assert_eq!(*expected, candidate.eject_value(), "({} - {})", a.eject_value(), b.eject_value());
            assert_count!(Sub(Field, Field) => Field, &(a.eject_mode(), b.eject_mode()));
            assert_output_mode!(Sub(Field, Field) => Field, &(CircuitType::from(a), CircuitType::from(b)), candidate);
        });
    }

    fn run_test(mode_a: Mode, mode_b: Mode) {
        let mut rng = TestRng::default();

        for i in 0..ITERATIONS {
            let first = Uniform::rand(&mut rng);
            let second = Uniform::rand(&mut rng);

            let expected = first - second;
            let a = Field::<Circuit>::new(mode_a, first);
            let b = Field::<Circuit>::new(mode_b, second);

            let name = format!("Sub: a - b {}", i);
            check_sub(&name, &expected, &a, &b);
            let name = format!("SubAssign: a - b {}", i);
            check_sub_assign(&name, &expected, &a, &b);

            // Test identity.
            let name = format!("Sub: a - 0 {}", i);
            let zero = Field::<Circuit>::new(mode_b, console::Field::<<Circuit as Environment>::Network>::zero());
            check_sub(&name, &first, &a, &zero);
            let name = format!("SubAssign: a - 0 {}", i);
            check_sub_assign(&name, &first, &a, &zero);

            // Test negation.
            let name = format!("Sub: 0 - b {}", i);
            let zero = Field::<Circuit>::new(mode_a, console::Field::<<Circuit as Environment>::Network>::zero());
            check_sub(&name, &(-second), &zero, &b);
            let name = format!("SubAssign: 0 - b {}", i);
            check_sub_assign(&name, &(-second), &zero, &b);
        }
    }

    #[test]
    fn test_constant_plus_constant() {
        run_test(Mode::Constant, Mode::Constant);
    }

    #[test]
    fn test_constant_plus_public() {
        run_test(Mode::Constant, Mode::Public);
    }

    #[test]
    fn test_public_plus_constant() {
        run_test(Mode::Public, Mode::Constant);
    }

    #[test]
    fn test_constant_plus_private() {
        run_test(Mode::Constant, Mode::Private);
    }

    #[test]
    fn test_private_plus_constant() {
        run_test(Mode::Private, Mode::Constant);
    }

    #[test]
    fn test_public_plus_public() {
        run_test(Mode::Public, Mode::Public);
    }

    #[test]
    fn test_public_plus_private() {
        run_test(Mode::Public, Mode::Private);
    }

    #[test]
    fn test_private_plus_public() {
        run_test(Mode::Private, Mode::Public);
    }

    #[test]
    fn test_private_plus_private() {
        run_test(Mode::Private, Mode::Private);
    }

    #[test]
    fn test_0_minus_0() {
        let zero = console::Field::<<Circuit as Environment>::Network>::zero();

        let candidate = Field::<Circuit>::zero() - Field::zero();
        assert_eq!(zero, candidate.eject_value());

        let candidate = Field::<Circuit>::zero() - &Field::zero();
        assert_eq!(zero, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Public, zero) - Field::new(Mode::Public, zero);
        assert_eq!(zero, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Public, zero) - Field::new(Mode::Private, zero);
        assert_eq!(zero, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Private, zero) - Field::new(Mode::Private, zero);
        assert_eq!(zero, candidate.eject_value());
    }

    #[test]
    fn test_1_minus_0() {
        let zero = console::Field::<<Circuit as Environment>::Network>::zero();
        let one = console::Field::<<Circuit as Environment>::Network>::one();

        let candidate = Field::<Circuit>::one() - Field::zero();
        assert_eq!(one, candidate.eject_value());

        let candidate = Field::<Circuit>::one() - &Field::zero();
        assert_eq!(one, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Public, one) - Field::new(Mode::Public, zero);
        assert_eq!(one, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Public, one) - Field::new(Mode::Private, zero);
        assert_eq!(one, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Private, one) - Field::new(Mode::Private, zero);
        assert_eq!(one, candidate.eject_value());
    }

    #[test]
    fn test_1_minus_1() {
        let zero = console::Field::<<Circuit as Environment>::Network>::zero();
        let one = console::Field::<<Circuit as Environment>::Network>::one();

        let candidate = Field::<Circuit>::one() - Field::one();
        assert_eq!(zero, candidate.eject_value());

        let candidate = Field::<Circuit>::one() - &Field::one();
        assert_eq!(zero, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Public, one) - Field::new(Mode::Public, one);
        assert_eq!(zero, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Private, one) - Field::new(Mode::Public, one);
        assert_eq!(zero, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Private, one) - Field::new(Mode::Private, one);
        assert_eq!(zero, candidate.eject_value());
    }

    #[test]
    fn test_2_minus_1() {
        let one = console::Field::<<Circuit as Environment>::Network>::one();
        let two = one + one;

        let candidate_two = Field::<Circuit>::one() + Field::one();
        let candidate = candidate_two - Field::one();
        assert_eq!(one, candidate.eject_value());

        let candidate_two = Field::<Circuit>::one() + &Field::one();
        let candidate = candidate_two - &Field::one();
        assert_eq!(one, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Public, two) - Field::new(Mode::Public, one);
        assert_eq!(one, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Private, two) - Field::new(Mode::Public, one);
        assert_eq!(one, candidate.eject_value());

        let candidate = Field::<Circuit>::new(Mode::Private, two) - Field::new(Mode::Private, one);
        assert_eq!(one, candidate.eject_value());
    }
}