Add parallel versions of generate_prime and generate_safe_prime

src/lib.rs

@@ -25,5 +25,7 @@ pub use traits::RandomPrimeWithRng;
 
 #[cfg(feature = "default-rng")]
 pub use presets::{generate_prime, generate_safe_prime, is_prime, is_safe_prime};
+#[cfg(all(feature = "default-rng", feature = "rayon"))]
+pub use presets::{par_generate_prime, par_generate_safe_prime};
 #[cfg(feature = "rayon")]
 pub use presets::{par_generate_prime_with_rng, par_generate_safe_prime_with_rng};

src/presets.rs

@@ -19,6 +19,20 @@ pub fn generate_prime<T: Integer + RandomBits + RandomMod>(bit_length: u32) -> T
     generate_prime_with_rng(&mut OsRng, bit_length)
 }
 
+/// Returns a random prime of size `bit_length` using [`OsRng`] as the RNG.
+///
+/// See [`is_prime_with_rng`] for details about the performed checks.
+///
+/// Uses [`rayon`] to parallelize the prime search using `corecount/2` threads (but minimum 2).
+///
+/// Panics if `bit_length` is less than 2, or greater than the bit size of the target `Uint`.
+///
+/// Panics if the platform is unable to spawn threads.
+#[cfg(all(feature = "default-rng", feature = "rayon"))]
+pub fn par_generate_prime<T: Integer + RandomBits + RandomMod>(bit_length: u32, threadcount: usize) -> T {
+    par_generate_prime_with_rng(&mut OsRng, bit_length, threadcount)
+}
+
 /// Returns a random safe prime (that is, such that `(n - 1) / 2` is also prime) of size
 /// `bit_length` using [`OsRng`] as the RNG.
 ///
@@ -28,6 +42,21 @@ pub fn generate_safe_prime<T: Integer + RandomBits + RandomMod>(bit_length: u32)
     generate_safe_prime_with_rng(&mut OsRng, bit_length)
 }
 
+/// Returns a random safe prime (that is, such that `(n - 1) / 2` is also prime) of size
+/// `bit_length` using [`OsRng`] as the RNG.
+///
+/// See [`is_prime_with_rng`] for details about the performed checks.
+///
+/// Uses [`rayon`] to parallelize the prime search using `corecount/2` threads (but minimum 2).
+///
+/// Panics if `bit_length` is less than 3, or greater than the bit size of the target `Uint`.
+///
+/// Panics if the platform is unable to spawn threads.
+#[cfg(all(feature = "default-rng", feature = "rayon"))]
+pub fn par_generate_safe_prime<T: Integer + RandomBits + RandomMod>(bit_length: u32, threadcount: usize) -> T {
+    par_generate_safe_prime_with_rng(&mut OsRng, bit_length, threadcount)
+}
+
 /// Probabilistically checks if the given number is prime using [`OsRng`] as the RNG.
 ///
 /// See [`is_prime_with_rng`] for details about the performed checks.