Struct Histogram

pub struct Histogram { /* private fields */ }

the main datastructure

Implementations

impl Histogram

pub fn new() -> Histogram

create a new Histogram

Example

let mut h = Histogram::new();

pub fn configure() -> Config

configure a Histogram

Example

let mut h = Histogram::configure()
    .max_value(10_000)
    .build()
    .unwrap();

pub fn clear(&mut self)

clear the histogram data

Example

let mut h = Histogram::new();

h.increment(1);
assert_eq!(h.entries(), 1);
h.clear();
assert_eq!(h.entries(), 0);

pub fn increment(&mut self, value: u64) -> Result<(), &'static str>

increment the count for a value

Example

use histogram::Histogram;

let mut h = Histogram::new();

h.increment(1);
assert_eq!(h.get(1).unwrap(), 1);

pub fn increment_by( &mut self, value: u64, count: u64, ) -> Result<(), &'static str>

record additional counts for value

Example

let mut h = Histogram::new();

h.increment_by(1, 1);
assert_eq!(h.get(1).unwrap(), 1);

h.increment_by(2, 2);
assert_eq!(h.get(2).unwrap(), 2);

h.increment_by(10, 10);
assert_eq!(h.get(10).unwrap(), 10);

pub fn decrement(&mut self, value: u64) -> Result<(), &'static str>

decrement the count for a value. This functionality is best used to remove previously inserted from the histogram.

Example

let mut h = Histogram::new();

h.increment(1).unwrap();
assert_eq!(h.get(1).unwrap(), 1);
h.decrement(1).unwrap();
assert_eq!(h.get(1).unwrap(), 0);

pub fn decrement_by( &mut self, value: u64, count: u64, ) -> Result<(), &'static str>

remove count for value from histogram. This functionality is best used to remove previously inserted from the histogram.

Example

let mut h = Histogram::new();

h.increment_by(1, 1).unwrap();
h.increment_by(2, 2).unwrap();
h.decrement_by(1, 1).unwrap();

assert_eq!(h.get(2).unwrap(), 2);
assert_eq!(h.get(1).unwrap(), 0);

pub fn get(&self, value: u64) -> Option<u64>

get the count for a value

Example

let mut h = Histogram::new();
assert_eq!(h.get(1).unwrap(), 0);

pub fn percentile(&self, percentile: f64) -> Result<u64, &'static str>

return the value for the given percentile

Example

let mut h = Histogram::new();
for value in 1..1000 {
    h.increment(value).unwrap();
}

assert_eq!(h.percentile(50.0).unwrap(), 501);
assert_eq!(h.percentile(90.0).unwrap(), 901);
assert_eq!(h.percentile(99.0).unwrap(), 991);
assert_eq!(h.percentile(99.9).unwrap(), 999);

pub fn minimum(&self) -> Result<u64, &'static str>

convenience function for min

Example

let mut h = Histogram::new();
for value in 1..1000 {
    h.increment(value);
}
assert_eq!(h.minimum().unwrap(), 1);

pub fn maximum(&self) -> Result<u64, &'static str>

convenience function for max

Example

let mut h = Histogram::new();
for value in 1..1000 {
    h.increment(value);
}
assert_eq!(h.maximum().unwrap(), 999);

pub fn mean(&self) -> Result<u64, &'static str>

arithmetic mean approximation across the histogram

Example

let mut h = Histogram::new();
for value in 1..1000 {
    h.increment(value);
}
assert_eq!(h.mean().unwrap(), 500);

pub fn stdvar(&self) -> Result<u64, &'static str>

standard variance approximation across the histogram

Example

let mut h = Histogram::new();
for value in 1..11 {
    h.increment(value);
}
assert_eq!(h.stdvar().unwrap(), 9);

pub fn stddev(&self) -> Option<u64>

standard deviation approximation across the histogram

Example

let mut h = Histogram::new();

for value in 1..11 {
    h.increment(value);
}

assert_eq!(h.stddev().unwrap(), 3);

h.clear();

for value in 1..4 {
    h.increment(value);
}
for _ in 0..26 {
    h.increment(1);
}

assert_eq!(h.stddev().unwrap(), 1);

pub fn merge(&mut self, other: &Histogram)

merge one Histogram into another Histogram

Example

let mut a = Histogram::new();
let mut b = Histogram::new();

assert_eq!(a.entries(), 0);
assert_eq!(b.entries(), 0);

a.increment(1);
b.increment(2);

assert_eq!(a.entries(), 1);
assert_eq!(b.entries(), 1);

a.merge(&mut b);

assert_eq!(a.entries(), 2);
assert_eq!(a.get(1).unwrap(), 1);
assert_eq!(a.get(2).unwrap(), 1);

pub fn entries(&self) -> u64

return the number of entries in the Histogram

Example

let mut h = Histogram::new();

assert_eq!(h.entries(), 0);
h.increment(1);
assert_eq!(h.entries(), 1);

pub fn buckets_total(&self) -> u64

return the number of buckets in the Histogram

Example

let mut h = Histogram::new();

assert!(h.buckets_total() > 1);

Trait Implementations

impl Clone for Histogram

fn clone(&self) -> Histogram

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Histogram

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Histogram

fn default() -> Histogram

Returns the “default value” for a type.

impl<'a> IntoIterator for &'a Histogram

type Item = Bucket

The type of the elements being iterated over.

type IntoIter = Iter<'a>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.