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Split benchmark functions into modules

This commit is contained in:
Timothy Warren 2022-03-11 13:24:30 -05:00
parent 8f43327b54
commit adbdc3b8eb
5 changed files with 291 additions and 280 deletions
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85
src/factorial.rs Normal file
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use std::f64::consts::{E, PI};
/// Calculate the value of a factorial iteratively
///
/// Can calculate up to 34! using native unsigned 128 bit integers.
///
/// Example:
/// ```rust
/// use rusty_fib_facts::factorial;
///
/// let valid = factorial(3); // Some(6)
/// # assert_eq!(6, valid.unwrap());
///
/// let invalid = factorial(35); // None
/// # assert!(invalid.is_none());
/// ```
#[inline]
pub fn it_factorial(n: usize) -> Option<u128> {
let mut total: u128 = 1;
if matches!(n, 0 | 1) {
Some(1u128)
} else {
for x in 1..=n {
total = total.checked_mul(x as u128)?;
}
Some(total)
}
}
/// Calculate the value of a factorial recursively
///
/// Can calculate up to 34! using native unsigned 128 bit integers.
///
/// Example:
/// ```rust
/// use rusty_fib_facts::factorial;
///
/// let valid = factorial(3); // Some(6)
/// # assert_eq!(6, valid.unwrap());
///
/// let invalid = factorial(35); // None
/// # assert!(invalid.is_none());
/// ```
#[inline]
pub fn factorial(n: usize) -> Option<u128> {
if matches!(n, 0 | 1) {
Some(1u128)
} else {
let prev = factorial(n - 1)?;
(n as u128).checked_mul(prev)
}
}
/// Approximates a factorial using Stirling's approximation
///
/// Based on https://en.wikipedia.org/wiki/Stirling's_approximation
///
/// Can approximate up to ~ 170.624!
///
/// Example:
/// ```rust
/// use rusty_fib_facts::approx_factorial;
///
/// let valid = approx_factorial(170.6); // Some(..)
/// # assert!(valid.is_some());
///
/// let invalid = approx_factorial(171.0); // None
/// # assert!(invalid.is_none());
/// ```
#[inline]
pub fn approx_factorial(n: f64) -> Option<f64> {
let power = (n / E).powf(n);
let root = (PI * 2.0 * n).sqrt();
let res = power * root;
if res >= std::f64::MIN && res <= std::f64::MAX {
Some(res)
} else {
None
}
}

103
src/fibonacci.rs Normal file
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/// Calculate a number in the fibonacci sequence,
/// using recursion and a lookup table
///
/// Can calculate up to 186 using native unsigned 128 bit integers.
///
/// Example:
/// ```rust
/// use rusty_fib_facts::mem_fibonacci;
///
/// let valid = mem_fibonacci(45); // Some(1134903170)
/// # assert_eq!(1134903170, mem_fibonacci(45).unwrap());
/// # assert!(valid.is_some());
///
/// let invalid = mem_fibonacci(187); // None
/// # assert!(invalid.is_none());
/// ```
#[inline]
pub fn mem_fibonacci(n: usize) -> Option<u128> {
let mut table = [0u128; 187];
table[0] = 0;
table[1] = 1;
table[2] = 1;
/// Actual calculating function for `fibonacci`
fn f(n: usize, table: &mut [u128]) -> Option<u128> {
if n < 2 {
// The first values are predefined.
return Some(table[n]);
}
if n > 186 {
return None;
}
match table[n] {
// The lookup array starts out zeroed, so a zero
// is a not yet calculated value
0 => {
let a = f(n - 1, table)?;
let b = f(n - 2, table)?;
table[n] = a + b;
Some(table[n])
}
x => Some(x),
}
}
f(n, &mut table)
}
/// Calculate a number in the fibonacci sequence,
/// using naive recursion
///
/// REALLY SLOW
///
/// Can calculate up to 186 using native unsigned 128 bit integers.
#[inline]
pub fn rec_fibonacci(n: usize) -> Option<u128> {
if matches!(n, 0 | 1) {
Some(n as u128)
} else {
let a = rec_fibonacci(n - 1)?;
let b = rec_fibonacci(n - 2)?;
a.checked_add(b)
}
}
/// Calculate a number in the fibonacci sequence,
///
/// Can calculate up to 186 using native unsigned 128 bit integers.
///
/// Example:
/// ```rust
/// use rusty_fib_facts::fibonacci;
///
/// let valid = fibonacci(45); // Some(1134903170)
/// # assert_eq!(1134903170, fibonacci(45).unwrap());
/// # assert!(valid.is_some());
///
/// let invalid = fibonacci(187); // None
/// # assert!(invalid.is_none());
/// ```
#[inline]
pub fn fibonacci(n: usize) -> Option<u128> {
let mut a: u128 = 0;
let mut b: u128 = 1;
if matches!(n, 0 | 1) {
Some(n as u128)
} else {
for _ in 0..n - 1 {
let c: u128 = a.checked_add(b)?;
a = b;
b = c;
}
Some(b)
}
}

94
src/gcd.rs Normal file
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use std::cmp::{max, min};
pub trait UnsignedGCD {
/// Find the greatest common denominator of two numbers
fn gcd(a: Self, b: Self) -> Self;
/// Euclid gcd algorithm
fn e_gcd(a: Self, b: Self) -> Self;
/// Stein gcd algorithm
fn stein_gcd(a: Self, b: Self) -> Self;
/// Find the least common multiple of two numbers
fn lcm(a: Self, b: Self) -> Self;
}
macro_rules! impl_unsigned {
($($Type: ty),* ) => {
$(
impl UnsignedGCD for $Type {
/// Implementation based on
/// [Binary GCD algorithm](https://en.wikipedia.org/wiki/Binary_GCD_algorithm)
fn gcd(a: $Type, b: $Type) -> $Type {
if a == b {
return a;
} else if a == 0 {
return b;
} else if b == 0 {
return a;
}
let a_even = a % 2 == 0;
let b_even = b % 2 == 0;
if a_even {
if b_even {
// Both a & b are even
return Self::gcd(a >> 1, b >> 1) << 1;
} else if !b_even {
// b is odd
return Self::gcd(a >> 1, b);
}
}
// a is odd, b is even
if (!a_even) && b_even {
return Self::gcd(a, b >> 1);
}
if a > b {
return Self::gcd((a - b) >> 1, b);
}
Self::gcd((b - a) >> 1, a)
}
fn e_gcd(x: $Type, y: $Type) -> $Type {
let mut x = x;
let mut y = y;
while y != 0 {
let t = y;
y = x % y;
x = t;
}
x
}
fn stein_gcd(a: Self, b: Self) -> Self {
match ((a, b), (a & 1, b & 1)) {
((x, y), _) if x == y => y,
((0, x), _) | ((x, 0), _) => x,
((x, y), (0, 1)) | ((y, x), (1, 0)) => Self::stein_gcd(x >> 1, y),
((x, y), (0, 0)) => Self::stein_gcd(x >> 1, y >> 1) << 1,
((x, y), (1, 1)) => {
let (x, y) = (min(x, y), max(x, y));
Self::stein_gcd((y - x) >> 1, x)
}
_ => unreachable!(),
}
}
fn lcm(a: $Type, b: $Type) -> $Type {
if (a == 0 && b == 0) {
return 0;
}
a * b / Self::gcd(a, b)
}
}
)*
};
}
impl_unsigned!(u8, u16, u32, u64, u128, usize);

286
src/lib.rs
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//! Implementations of common algorithms to benchmark
#![forbid(unsafe_code)]
mod gcd;
pub mod parallel;
pub mod factorial;
pub mod fibonacci;
use std::cmp::{max, min};
use std::f64::consts::{E, PI};
/// Calculate a number in the fibonacci sequence,
/// using recursion and a lookup table
///
/// Can calculate up to 186 using native unsigned 128 bit integers.
///
/// Example:
/// ```rust
/// use rusty_fib_facts::mem_fibonacci;
///
/// let valid = mem_fibonacci(45); // Some(1134903170)
/// # assert_eq!(1134903170, mem_fibonacci(45).unwrap());
/// # assert!(valid.is_some());
///
/// let invalid = mem_fibonacci(187); // None
/// # assert!(invalid.is_none());
/// ```
#[inline]
pub fn mem_fibonacci(n: usize) -> Option<u128> {
let mut table = [0u128; 187];
table[0] = 0;
table[1] = 1;
table[2] = 1;
pub use gcd::UnsignedGCD;
pub use factorial::*;
pub use fibonacci::*;
/// Actual calculating function for `fibonacci`
fn f(n: usize, table: &mut [u128]) -> Option<u128> {
if n < 2 {
// The first values are predefined.
return Some(table[n]);
}
if n > 186 {
return None;
}
match table[n] {
// The lookup array starts out zeroed, so a zero
// is a not yet calculated value
0 => {
let a = f(n - 1, table)?;
let b = f(n - 2, table)?;
table[n] = a + b;
Some(table[n])
}
x => Some(x),
}
}
f(n, &mut table)
}
/// Calculate a number in the fibonacci sequence,
/// using naive recursion
///
/// REALLY SLOW
///
/// Can calculate up to 186 using native unsigned 128 bit integers.
#[inline]
pub fn rec_fibonacci(n: usize) -> Option<u128> {
if matches!(n, 0 | 1) {
Some(n as u128)
} else {
let a = rec_fibonacci(n - 1)?;
let b = rec_fibonacci(n - 2)?;
a.checked_add(b)
}
}
/// Calculate a number in the fibonacci sequence,
///
/// Can calculate up to 186 using native unsigned 128 bit integers.
///
/// Example:
/// ```rust
/// use rusty_fib_facts::fibonacci;
///
/// let valid = fibonacci(45); // Some(1134903170)
/// # assert_eq!(1134903170, fibonacci(45).unwrap());
/// # assert!(valid.is_some());
///
/// let invalid = fibonacci(187); // None
/// # assert!(invalid.is_none());
/// ```
#[inline]
pub fn fibonacci(n: usize) -> Option<u128> {
let mut a: u128 = 0;
let mut b: u128 = 1;
if matches!(n, 0 | 1) {
Some(n as u128)
} else {
for _ in 0..n - 1 {
let c: u128 = a.checked_add(b)?;
a = b;
b = c;
}
Some(b)
}
}
/// Calculate the value of a factorial iteratively
///
/// Can calculate up to 34! using native unsigned 128 bit integers.
///
/// Example:
/// ```rust
/// use rusty_fib_facts::factorial;
///
/// let valid = factorial(3); // Some(6)
/// # assert_eq!(6, valid.unwrap());
///
/// let invalid = factorial(35); // None
/// # assert!(invalid.is_none());
/// ```
#[inline]
pub fn it_factorial(n: usize) -> Option<u128> {
let mut total: u128 = 1;
if matches!(n, 0 | 1) {
Some(1u128)
} else {
for x in 1..=n {
total = total.checked_mul(x as u128)?;
}
Some(total)
}
}
/// Calculate the value of a factorial recursively
///
/// Can calculate up to 34! using native unsigned 128 bit integers.
///
/// Example:
/// ```rust
/// use rusty_fib_facts::factorial;
///
/// let valid = factorial(3); // Some(6)
/// # assert_eq!(6, valid.unwrap());
///
/// let invalid = factorial(35); // None
/// # assert!(invalid.is_none());
/// ```
#[inline]
pub fn factorial(n: usize) -> Option<u128> {
if matches!(n, 0 | 1) {
Some(1u128)
} else {
let prev = factorial(n - 1)?;
(n as u128).checked_mul(prev)
}
}
/// Approximates a factorial using Stirling's approximation
///
/// Based on https://en.wikipedia.org/wiki/Stirling's_approximation
///
/// Can approximate up to ~ 170.624!
///
/// Example:
/// ```rust
/// use rusty_fib_facts::approx_factorial;
///
/// let valid = approx_factorial(170.6); // Some(..)
/// # assert!(valid.is_some());
///
/// let invalid = approx_factorial(171.0); // None
/// # assert!(invalid.is_none());
/// ```
#[inline]
pub fn approx_factorial(n: f64) -> Option<f64> {
let power = (n / E).powf(n);
let root = (PI * 2.0 * n).sqrt();
let res = power * root;
if res >= std::f64::MIN && res <= std::f64::MAX {
Some(res)
} else {
None
}
}
pub trait UnsignedGCD {
/// Find the greatest common denominator of two numbers
fn gcd(a: Self, b: Self) -> Self;
/// Euclid gcd algorithm
fn e_gcd(a: Self, b: Self) -> Self;
/// Stein gcd algorithm
fn stein_gcd(a: Self, b: Self) -> Self;
/// Find the least common multiple of two numbers
fn lcm(a: Self, b: Self) -> Self;
}
macro_rules! impl_unsigned {
($($Type: ty),* ) => {
$(
impl UnsignedGCD for $Type {
/// Implementation based on
/// [Binary GCD algorithm](https://en.wikipedia.org/wiki/Binary_GCD_algorithm)
fn gcd(a: $Type, b: $Type) -> $Type {
if a == b {
return a;
} else if a == 0 {
return b;
} else if b == 0 {
return a;
}
let a_even = a % 2 == 0;
let b_even = b % 2 == 0;
if a_even {
if b_even {
// Both a & b are even
return Self::gcd(a >> 1, b >> 1) << 1;
} else if !b_even {
// b is odd
return Self::gcd(a >> 1, b);
}
}
// a is odd, b is even
if (!a_even) && b_even {
return Self::gcd(a, b >> 1);
}
if a > b {
return Self::gcd((a - b) >> 1, b);
}
Self::gcd((b - a) >> 1, a)
}
fn e_gcd(x: $Type, y: $Type) -> $Type {
let mut x = x;
let mut y = y;
while y != 0 {
let t = y;
y = x % y;
x = t;
}
x
}
fn stein_gcd(a: Self, b: Self) -> Self {
match ((a, b), (a & 1, b & 1)) {
((x, y), _) if x == y => y,
((0, x), _) | ((x, 0), _) => x,
((x, y), (0, 1)) | ((y, x), (1, 0)) => Self::stein_gcd(x >> 1, y),
((x, y), (0, 0)) => Self::stein_gcd(x >> 1, y >> 1) << 1,
((x, y), (1, 1)) => {
let (x, y) = (min(x, y), max(x, y));
Self::stein_gcd((y - x) >> 1, x)
}
_ => unreachable!(),
}
}
fn lcm(a: $Type, b: $Type) -> $Type {
if (a == 0 && b == 0) {
return 0;
}
a * b / Self::gcd(a, b)
}
}
)*
};
}
impl_unsigned!(u8, u16, u32, u64, u128, usize);
#[cfg(test)]
#[cfg(not(tarpaulin_include))]

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src/parallel.rs Normal file
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//! Parallel Algorithms
//!
//! These algorithms use threads to benchmark parallel operations