TMtxMDScaling Class

public class TMtxMDScaling : TMtxComponent

Performs multidimensional scaling.

Use TMtxMDScaling component to perform multidimensional scaling on dataset.

How to use TMtxMDScaling component?
1. Drop a TMtxMDScaling component on the form. 2. Set Dew.Stats.TMtxMDScaling.DataFormat property to define how data will be interpreted. Data can be interpreted as dissimilarities matrix, similarities matrix or raw data matrix. 3. Define Dew.Stats.TMtxMDScaling.Data, the matrix representing dissimilarities matrix, similarities matrix or raw data.
4. Set Dew.Stats.TMtxMDScaling.Dimensions to define number of variables in reduced space. 5. Set Dew.Stats.TMtxMDScaling.DistanceMethod to define how pairwise distance will be calculated. 6. Set Dew.Stats.TMtxMDScaling.ScalingMethod to define scaling algorithm. Currently only metric (classical) multidimensional scaling algorithm is supported. 7. Call the Dew.Stats.TMtxMDScaling.Recalc method to trigger calculation.

Results:
1. Dew.Stats.TMtxMDScaling.Y : Point coordinates in reduced space. 2. Dew.Stats.TMtxMDScaling.EigenValues : Eigenvalues in reduced space, sorted in descending order. 3. Dew.Stats.TMtxMDScaling.DHat : Estimated dissimilarities matrix. 4. Dew.Stats.TMtxMDScaling.Stress : Calculated stress factor.

Examples

csharp

using Dew.Stats;
using Dew.Stats.Units;
using Dew.Math;
namespace Dew.Examples
{
    private void Example(StatTools.TMtxMDScaling mds)
    {
        // similarities matrix (symmetric with 1.0 on diagonal)
        mds.Data.SetIt(5,5,false, new double[] {
            1.00, 0.3, 0.2, 0.25, 0.33,
            0.30, 1.0, 0.11, 0.21, 0.8,
            0.20, 0.11, 1.0, 0.40, 0.5,
            0.25, 0.21, 1.0, 0.10, 0.05,
            0.33, 0.80, 0.5, 0.05, 1.00});
        mds.DataFormat = TMDDataFormat.mdFormatSimilarities;
        // use "standard" Euclidian metric
        mds.DistanceMethod = TPWDistMethod.pwdistEuclidian;
        // define number of desired dimensions (1)
        mds.Dimensions = 1;
        // Do the math
        mds.Recalc();
        // check Stress, DHat, EigeValues to evaluate GOF if (1) dimension is used
    }
}

Properties

Name	Type	Description
AutoUpdate	Boolean	If true then changing any of the TMtxPCA properties will trigger the Dew.Stats.TMtxMDScaling.Recalc method.
BlockAssign	Boolean	Block streaming of specific properties when storing only a "template".
D	TMtx	Used dissimilarities matrix.
Data	TMtx	Data to be analyzed by MDS.
DataFormat	TMDDataFormat	Data format.
DHat	TMtx	Estimated dissimilarities matrix.
Dimensions	Int32	Reduced dimension size.
Dirty	Boolean	When any of the TMtxMDScaling properties changes, this property is automatically set to true.
DistanceMethod	TPWDistMethod	Metric for distance calculation.
EditorActive	Boolean	Returns True, if the component editor is displayed.
EigenValues	TVec	Reduced space eigenvalues.
Reference	TReferenceList	Stores a list of components that have to be notified, when this component is destroyed.
ScalingMethod	TMDScalingMethod	Defines multidimensional scaling algorithm.
Stress	Double	Returns multidimensional scaling stress value which is an estimate for GOF.
Y	TMtx	Reduced space point coordinates.

Methods

Name	Description
AllowStreaming	Returns the negatated value of BlockAssign.
Assign	Assign values of all published properties from Source.
AssignTemplate	Assign values of "template-like" published properties from Source.
EditorClass	To be overriden in descendanr classses.
LoadFromStream	Load the component from Src stream.
LoadTemplateFromFile	Load a template from file.
LoadTemplateFromStream	Load a template from stream.
Recalc	Triggers MDScalling recalculation.
Reset	Reset is called after loading the data from stream or file.
SaveTemplateToFile	Save template to file.
SaveTemplateToStream	Save template to stream.
SaveToStream	Save the component to Dst stream.