Enum ViolationType 

pub enum ViolationType {
    BeyondLimits,
    NineOneSide,
    SixTrend,
    FourteenAlternating,
    TwoOfThreeBeyond2Sigma,
    FourOfFiveBeyond1Sigma,
    FifteenWithin1Sigma,
    EightBeyond1Sigma,
}

Types of control chart violations based on Nelson’s eight rules.

Each variant corresponds to one of Nelson’s tests for special causes of variation.

Reference

Nelson, L.S. (1984). “The Shewhart Control Chart — Tests for Special Causes”, Journal of Quality Technology 16(4), pp. 237-239.

Variants

BeyondLimits

Point beyond control limits (Nelson Rule 1).

A single point falls outside the 3-sigma control limits.

NineOneSide

9 points in a row on same side of center line (Nelson Rule 2).

Indicates a sustained shift in the process mean.

SixTrend

6 points in a row steadily increasing or decreasing (Nelson Rule 3).

Indicates a trend in the process.

FourteenAlternating

14 points in a row alternating up and down (Nelson Rule 4).

Indicates systematic variation (e.g., two alternating streams).

TwoOfThreeBeyond2Sigma

2 out of 3 points beyond 2 sigma on same side (Nelson Rule 5).

An early warning of a potential shift.

FourOfFiveBeyond1Sigma

4 out of 5 points beyond 1 sigma on same side (Nelson Rule 6).

Indicates a small sustained shift.

FifteenWithin1Sigma

15 points in a row within 1 sigma of center line (Nelson Rule 7).

Indicates stratification — reduced variation suggesting mixed streams.

EightBeyond1Sigma

8 points in a row beyond 1 sigma on either side (Nelson Rule 8).

Indicates a mixture pattern — points avoid the center zone.

Trait Implementations

impl Clone for ViolationType

fn clone(&self) -> ViolationType

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ViolationType

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

Formats the value using the given formatter.

impl PartialEq for ViolationType

fn eq(&self, other: &ViolationType) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for ViolationType

impl Eq for ViolationType

impl StructuralPartialEq for ViolationType