chore(core): remove log and modular standard_dev

tfhe/src/core_crypto/commons/dispersion.rs

@@ -6,7 +6,6 @@
 //! we rely on different representations for this quantity:
 //!
 //! + $\sigma$ can be encoded in the [`StandardDev`] type.
-//! + $p$ can be encoded in the [`LogStandardDev`] type.
 //! + $\sigma^2$ can be encoded in the [`Variance`] type.
 //!
 //! In any of those cases, the corresponding type implements the `DispersionParameter` trait,
@@ -28,96 +27,15 @@ pub trait DispersionParameter: Copy {
     fn get_standard_dev(&self) -> StandardDev;
     /// Return the variance of the distribution, i.e. $\sigma^2 = 2^{2p}$.
     fn get_variance(&self) -> Variance;
-    /// Return base 2 logarithm of the standard deviation of the distribution, i.e.
-    /// $\log\_2(\sigma)=p$
-    fn get_log_standard_dev(&self) -> LogStandardDev;
-    /// For a `Uint` type representing $\mathbb{Z}/2^q\mathbb{Z}$, we return $2^{q-p}$.
-    fn get_modular_standard_dev(&self, log2_modulus: u32) -> ModularStandardDev;
 
     /// For a `Uint` type representing $\mathbb{Z}/2^q\mathbb{Z}$, we return $2^{2(q-p)}$.
     fn get_modular_variance(&self, log2_modulus: u32) -> ModularVariance;
-
-    /// For a `Uint` type representing $\mathbb{Z}/2^q\mathbb{Z}$, we return $q-p$.
-    fn get_modular_log_standard_dev(&self, log2_modulus: u32) -> ModularLogStandardDev;
 }
 
 fn log2_modulus_to_modulus(log2_modulus: u32) -> f64 {
     2.0f64.powi(log2_modulus as i32)
 }
 
-/// A distribution parameter that uses the base-2 logarithm of the standard deviation as
-/// representation.
-///
-/// # Example:
-///
-/// ```rust
-/// use tfhe::core_crypto::commons::dispersion::{DispersionParameter, LogStandardDev};
-/// let params = LogStandardDev::from_log_standard_dev(-25.);
-/// assert_eq!(params.get_standard_dev().0, 2_f64.powf(-25.));
-/// assert_eq!(params.get_log_standard_dev().0, -25.);
-/// assert_eq!(params.get_variance().0, 2_f64.powf(-25.).powi(2));
-/// assert_eq!(
-///     params.get_modular_standard_dev(32).value,
-///     2_f64.powf(32. - 25.)
-/// );
-/// assert_eq!(params.get_modular_log_standard_dev(32).value, 32. - 25.);
-/// assert_eq!(
-///     params.get_modular_variance(32).value,
-///     2_f64.powf(32. - 25.).powi(2)
-/// );
-///
-/// let modular_params = LogStandardDev::from_modular_log_standard_dev(22., 32);
-/// assert_eq!(modular_params.get_standard_dev().0, 2_f64.powf(-10.));
-/// ```
-#[derive(Debug, Copy, Clone, PartialEq, PartialOrd)]
-pub struct LogStandardDev(pub f64);
-
-#[derive(Debug, Copy, Clone, PartialEq, PartialOrd)]
-pub struct ModularLogStandardDev {
-    pub value: f64,
-    pub modulus: f64,
-}
-
-impl LogStandardDev {
-    pub fn from_log_standard_dev(log_std: f64) -> Self {
-        Self(log_std)
-    }
-
-    pub fn from_modular_log_standard_dev(log_std: f64, log2_modulus: u32) -> Self {
-        Self(log_std - log2_modulus as f64)
-    }
-}
-
-impl DispersionParameter for LogStandardDev {
-    fn get_standard_dev(&self) -> StandardDev {
-        StandardDev(f64::powf(2., self.0))
-    }
-    fn get_variance(&self) -> Variance {
-        Variance(f64::powf(2., self.0 * 2.))
-    }
-    fn get_log_standard_dev(&self) -> Self {
-        Self(self.0)
-    }
-    fn get_modular_standard_dev(&self, log2_modulus: u32) -> ModularStandardDev {
-        ModularStandardDev {
-            value: f64::powf(2., log2_modulus as f64 + self.0),
-            modulus: log2_modulus_to_modulus(log2_modulus),
-        }
-    }
-    fn get_modular_variance(&self, log2_modulus: u32) -> ModularVariance {
-        ModularVariance {
-            value: f64::powf(2., (log2_modulus as f64 + self.0) * 2.),
-            modulus: log2_modulus_to_modulus(log2_modulus),
-        }
-    }
-    fn get_modular_log_standard_dev(&self, log2_modulus: u32) -> ModularLogStandardDev {
-        ModularLogStandardDev {
-            value: log2_modulus as f64 + self.0,
-            modulus: log2_modulus_to_modulus(log2_modulus),
-        }
-    }
-}
-
 /// A distribution parameter that uses the standard deviation as representation.
 ///
 /// # Example:
@@ -126,14 +44,8 @@ impl DispersionParameter for LogStandardDev {
 /// use tfhe::core_crypto::commons::dispersion::{DispersionParameter, StandardDev};
 /// let params = StandardDev::from_standard_dev(2_f64.powf(-25.));
 /// assert_eq!(params.get_standard_dev().0, 2_f64.powf(-25.));
-/// assert_eq!(params.get_log_standard_dev().0, -25.);
 /// assert_eq!(params.get_variance().0, 2_f64.powf(-25.).powi(2));
 /// assert_eq!(
-///     params.get_modular_standard_dev(32).value,
-///     2_f64.powf(32. - 25.)
-/// );
-/// assert_eq!(params.get_modular_log_standard_dev(32).value, 32. - 25.);
-/// assert_eq!(
 ///     params.get_modular_variance(32).value,
 ///     2_f64.powf(32. - 25.).powi(2)
 /// );
@@ -142,17 +54,15 @@ impl DispersionParameter for LogStandardDev {
 #[versionize(StandardDevVersions)]
 pub struct StandardDev(pub f64);
 
-#[derive(Debug, Copy, Clone, PartialEq, PartialOrd)]
-pub struct ModularStandardDev {
-    pub value: f64,
-    pub modulus: f64,
-}
-
 impl StandardDev {
     pub fn from_standard_dev(std: f64) -> Self {
         Self(std)
     }
 
+    pub fn from_log_standard_dev(log_std: f64) -> Self {
+        Self(2_f64.powf(log_std))
+    }
+
     pub fn from_modular_standard_dev(std: f64, log2_modulus: u32) -> Self {
         Self(std / 2_f64.powf(log2_modulus as f64))
     }
@@ -165,27 +75,12 @@ impl DispersionParameter for StandardDev {
     fn get_variance(&self) -> Variance {
         Variance(self.0.powi(2))
     }
-    fn get_log_standard_dev(&self) -> LogStandardDev {
-        LogStandardDev(self.0.log2())
-    }
-    fn get_modular_standard_dev(&self, log2_modulus: u32) -> ModularStandardDev {
-        ModularStandardDev {
-            value: 2_f64.powf(log2_modulus as f64 + self.0.log2()),
-            modulus: log2_modulus_to_modulus(log2_modulus),
-        }
-    }
     fn get_modular_variance(&self, log2_modulus: u32) -> ModularVariance {
         ModularVariance {
             value: 2_f64.powf(2. * (log2_modulus as f64 + self.0.log2())),
             modulus: log2_modulus_to_modulus(log2_modulus),
         }
     }
-    fn get_modular_log_standard_dev(&self, log2_modulus: u32) -> ModularLogStandardDev {
-        ModularLogStandardDev {
-            value: log2_modulus as f64 + self.0.log2(),
-            modulus: log2_modulus_to_modulus(log2_modulus),
-        }
-    }
 }
 
 /// A distribution parameter that uses the variance as representation
@@ -196,14 +91,8 @@ impl DispersionParameter for StandardDev {
 /// use tfhe::core_crypto::commons::dispersion::{DispersionParameter, Variance};
 /// let params = Variance::from_variance(2_f64.powi(-50));
 /// assert_eq!(params.get_standard_dev().0, 2_f64.powf(-25.));
-/// assert_eq!(params.get_log_standard_dev().0, -25.);
 /// assert_eq!(params.get_variance().0, 2_f64.powf(-25.).powi(2));
 /// assert_eq!(
-///     params.get_modular_standard_dev(32).value,
-///     2_f64.powf(32. - 25.)
-/// );
-/// assert_eq!(params.get_modular_log_standard_dev(32).value, 32. - 25.);
-/// assert_eq!(
 ///     params.get_modular_variance(32).value,
 ///     2_f64.powf(32. - 25.).powi(2)
 /// );
@@ -234,25 +123,10 @@ impl DispersionParameter for Variance {
     fn get_variance(&self) -> Self {
         Self(self.0)
     }
-    fn get_log_standard_dev(&self) -> LogStandardDev {
-        LogStandardDev(self.0.sqrt().log2())
-    }
-    fn get_modular_standard_dev(&self, log2_modulus: u32) -> ModularStandardDev {
-        ModularStandardDev {
-            value: 2_f64.powf(log2_modulus as f64 + self.0.sqrt().log2()),
-            modulus: log2_modulus_to_modulus(log2_modulus),
-        }
-    }
     fn get_modular_variance(&self, log2_modulus: u32) -> ModularVariance {
         ModularVariance {
             value: 2_f64.powf(2. * (log2_modulus as f64 + self.0.sqrt().log2())),
             modulus: log2_modulus_to_modulus(log2_modulus),
         }
     }
-    fn get_modular_log_standard_dev(&self, log2_modulus: u32) -> ModularLogStandardDev {
-        ModularLogStandardDev {
-            value: log2_modulus as f64 + self.0.sqrt().log2(),
-            modulus: log2_modulus_to_modulus(log2_modulus),
-        }
-    }
 }

tfhe/src/core_crypto/fft_impl/fft64/crypto/wop_pbs/tests.rs

@@ -1,7 +1,7 @@
 use super::*;
 use crate::core_crypto::algorithms::slice_algorithms::*;
 use crate::core_crypto::algorithms::test::{FftWopPbsKeys, FftWopPbsTestParams};
-use crate::core_crypto::commons::dispersion::LogStandardDev;
+use crate::core_crypto::commons::dispersion::StandardDev;
 use crate::core_crypto::commons::math::decomposition::SignedDecomposer;
 use crate::core_crypto::commons::test_tools;
 use crate::core_crypto::fft_impl::common::tests::gen_keys_or_get_from_cache_if_enabled;
@@ -103,7 +103,7 @@ pub fn test_extract_bits() {
     let level_ksk = DecompositionLevelCount(7);
     let base_log_ksk = DecompositionBaseLog(4);
 
-    let std = LogStandardDev::from_log_standard_dev(-60.);
+    let std = StandardDev::from_log_standard_dev(-60.);
     let noise_distribution = DynamicDistribution::new_gaussian(std);
 
     let ciphertext_modulus = CiphertextModulus::new_native();
@@ -266,7 +266,7 @@ fn test_circuit_bootstrapping_binary() {
     let level_count_cbs = DecompositionLevelCount(1);
     let base_log_cbs = DecompositionBaseLog(10);
 
-    let std = LogStandardDev::from_log_standard_dev(-60.);
+    let std = StandardDev::from_log_standard_dev(-60.);
     let noise_distribution = DynamicDistribution::new_gaussian(std);
 
     let ciphertext_modulus = CiphertextModulus::new_native();
@@ -451,7 +451,7 @@ pub fn test_cmux_tree() {
     // Define settings for an insecure toy example
     let polynomial_size = PolynomialSize(512);
     let glwe_dimension = GlweDimension(1);
-    let std = LogStandardDev::from_log_standard_dev(-60.);
+    let std = StandardDev::from_log_standard_dev(-60.);
     let noise_distribution = DynamicDistribution::new_gaussian(std);
     let level = DecompositionLevelCount(3);
     let base_log = DecompositionBaseLog(6);