| LinkageWardLinkage Method |
Computes the distance between two clusters using Ward's method.
Namespace: CenterSpace.NMath.CoreAssembly: NMath (in NMath.dll) Version: 7.4
Syntax public static double WardLinkage(
double Drp,
double Drq,
double Dpq,
double Nr,
double Np,
double Nq
)
Public Shared Function WardLinkage (
Drp As Double,
Drq As Double,
Dpq As Double,
Nr As Double,
Np As Double,
Nq As Double
) As Double
public:
static double WardLinkage(
double Drp,
double Drq,
double Dpq,
double Nr,
double Np,
double Nq
)
static member WardLinkage :
Drp : float *
Drq : float *
Dpq : float *
Nr : float *
Np : float *
Nq : float -> float
Parameters
- Drp Double
- The distance between R and P.
- Drq Double
- The distance between R and Q.
- Dpq Double
- The distance between P and Q.
- Nr Double
- The number of objects in R.
- Np Double
- The number of objects in P.
- Nq Double
- The number of objects in Q.
Return Value
DoubleThe distance between R and P + Q.
Remarks
During cluster analysis when two groups P and Q are united, a linkage
function computes the distance between the new group P + Q and
another group R.
Ward's method uses an analysis of variance approach to evaluate
the distances between clusters. The smaller the increase in the total
within-group sum of squares as a result of joining two clusters, the "closer"
they are. The within-group sum of squares of a cluster is defined as the sum
of the squares of the distance between all objects in the cluster and the
centroid of the cluster. Ward's method tends to produce compact groups of
well-distributed size.
See Also