[R] CLARA

[optimisation1.stagiaire@lagardere-active.com]

I need informations about the clara routine. The on-line doc say that the
argument stand is a logical, indicating if the measurements in x are
standardized before calculating the dissimilarities. Measurements are
standardized for each variable (column), by subtracting the variable's mean
value and dividing by the variable's mean absolute deviation. If we note
STAND = TRUE, I suppose that the data will not be standardized before
clustering. On the contrary, STAND = FALSE means that the data will be
standardized before clustering.
Each sub-dataset is partitioned into k clusters using the same algorithm as
in pam. But the pam routine argument stand is a logical; if true, the
measurements in x are standardized before calculating the dissimilarities.
Measurements are standardized for each variable (column), by subtracting
the variable's mean value and dividing by the variable's mean absolute
deviation. If x is already a dissimilarity matrix, then this argument will
be ignored. If we note STAND = TRUE, I suppose that the data will be
standardized.

There is a big difference as clara and pam use nearly the same algorithm.

I need to use clara because I have a large dataset. Could help me about the
argument stand ? May I have to standardize my datas with excel before ? If
yes, what I have to write : STAND = ?? ?

Best regards,
Cordialement,

Régis CHARIGNON
Service Optimisation
Direct Line: +33 (0)1 47 23 21 44
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Lagardère Active Publicité
28, rue François 1er,  75008 Paris

 http://www.lagardere-active-pub.com


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