NpChart Class

A v2 SPC chart for monitoring the number of nonconforming items in a sample of fixed size (NP chart). Implements the full Unfitted → Fitted → Deployed → Apply lifecycle defined by ControlChart.

Definition

Namespace: Numerics.NET.Statistics.ProcessControl
Assembly: Numerics.NET (in Numerics.NET.dll) Version: 10.4.0

public sealed class NpChart : ControlChart<NpChart>

Visual Basic

Public NotInheritable Class NpChart
	Inherits ControlChart(Of NpChart)

C++/CLI

public ref class NpChart sealed : public ControlChart<NpChart^>

[<SealedAttribute>]
type NpChart = 
    class
        inherit ControlChart<NpChart>
    end

Inheritance: Object → ControlChart → ControlChart<NpChart> → NpChart

Remarks

The NP chart is used when the number of nonconforming items per subgroup is being monitored and the subgroup size is constant. Phase-I control limits are estimated from a baseline data set; the deployed chart can then be serialized and applied to future subgroups without re-estimation.

Typical usage:

double[] baseline = { 4, 2, 6, 3, 5, 2, 4, 3 };
double sampleSize = 100.0;

// Phase I — establish limits
NpChart chart = new NpChart(Vector.Create(baseline), sampleSize);
chart.Analyze();

// Deploy for production monitoring
NpChart deployed = (NpChart)chart.Deploy();

// Persist and restore
string json = deployed.ToJson();
NpChart restored = NpChart.FromJson(json);

// Phase II — apply to new observations
double[] production = { 3, 5, 2, 4 };
NpChart applied = (NpChart)restored.Apply(Vector.Create(production));

Constructors

NpChart

Initializes a new NpChart in the Unfitted state from a vector of nonconforming counts and a fixed sample size.

Properties

AverageFractionNonconforming	Gets the pooled fraction nonconforming (p̄) computed during phase-I analysis. The chart center line equals n·p̄.
SampleSize	Gets the constant sample size used by this chart.
Series	Gets the NP chart series. Contains the analyzed nonconforming counts and the computed control limits.
State	Gets the current lifecycle state of this chart. (Inherited from ControlChart)

Methods

Analyze	Performs phase-I analysis, establishing control limits and transitioning the chart from Unfitted to Fitted. (Inherited from ControlChart)
Apply	Applies new observations to this Deployed chart and returns a new TChart in the Fitted state. (Inherited from ControlChart<TChart>)
CreateDeployed	Creates an NpChart directly in the Deployed state from externally supplied fitted parameters.
Deploy	Creates a new TChart in the Deployed state from this Fitted chart. (Inherited from ControlChart<TChart>)
Diagnose	Produces a diagnostic report for the current chart state. (Inherited from ControlChart)
Equals	Determines whether the specified object is equal to the current object. (Inherited from Object)
FromJson	Reconstructs an NpChart from a JSON string previously produced by ToJson().
GetHashCode	Serves as the default hash function. (Inherited from Object)
GetType	Gets the Type of the current instance. (Inherited from Object)
ToJson	Serializes this NpChart to a JSON string.
ToString	Returns a string that represents the current object. (Inherited from Object)