The Complete SPRLIB & ANNLIB

sammon_triangulate

- map a new point using an existing Sammon mapping (LOCAL)

SYNOPSIS

void sammon_triangulate (n1, n2, n3, vector, mapping)

ARGUMENTS

int n1 Index of the first nearest neighbour of point vector in the current Sammon mapping.
int n2 Index of the second nearest neighbour of point vector in the current Sammon mapping.
int n3 Index of the third nearest neighbour of point vector in the current Sammon mapping.
double *vector The vector to be triangulated (in original space).
double *mapping The mapped vector (in 2D mapping space).

RETURNS

The mapped point, in the vector mapping of length 2.

FUNCTION

A new point can be mapped using an existing Sammon mapping to 2D by looking at at most three neighbours. This triangulation method tries to preserve the distances between the mapped version of vector to the nearest neighbours with indices n1 and n2 as well as possible. In case there is more than one solution, n3 is used to make a decision.

NOTE

This function can only be used for mappings to 2D. It is called by sammon_triangulate_set.

SEE ALSO

sammon_triangulate_set

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