PROC VARCLUS: Computational Resources :: SAS/STAT(R) 9.2 User's Guide, Second Edition

The VARCLUS Procedure

Computational Resources

Let

$\text{[math]}$	$\text{[math]}$	$\text{[math]}$
$\text{[math]}$	$\text{[math]}$	$\text{[math]}$
$\text{[math]}$	$\text{[math]}$	$\text{[math]}$

It is assumed that, at each stage of clustering, the clusters all contain the same number of variables.

Time

The time required for the VARCLUS procedure to analyze a given data set varies greatly depending on the number of clusters requested, the number of iterations in both the alternating least-squares and search phases, and whether centroid or principal components are used.

The time required to compute the correlation matrix is roughly proportional to $\text{[math]}$ .

Default cluster initialization requires time roughly proportional to $\text{[math]}$ . Any other method of initialization requires time roughly proportional to $\text{[math]}$ .

In the alternating least-squares phase, each iteration requires time roughly proportional to $\text{[math]}$ if centroid components are used or

$\text{[math]}$

if principal components are used.

In the search phase, each iteration requires time roughly proportional to $\text{[math]}$ if centroid components are used or $\text{[math]}$ if principal components are used. The HIERARCHY option speeds up each iteration after the first split by as much as $\text{[math]}$ .

Memory

The amount of memory, in bytes, needed by the VARCLUS procedure is approximately

$\text{[math]}$

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