# [R] Transformation of dissimilarity or distance matrix

Jan_Svatos@eurotel.cz Jan_Svatos at eurotel.cz
Wed May 30 12:33:38 CEST 2001

```Dear List,

is there an elegant (or even not elegant) way how to transform
dissimilarity or distance matrix A
(or, in general, arbitrary symmetrical matrix) by transposition of rows and
columns into a form
closest to "block diagonal" matrix B?
The matrix A is adjusted the following way

A[A<epsilon] <-0 #(epsilon is given "small" number)

B: (in its ideal form)

b_{11}...b_{1i} 0...0
...
b_{i1}...b_{ii}
0...0          b_{i+1, i+1}

etc,
with "reasonable" number of blocks.
Dimensions of this problem: about 3000 rows (given) and about 30-45 blocks
(expected).

If there is some function for this task in "Matrix, multiv,..." packages,
then RTFM is a perfectly good answer.

Jan

--
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/- Jan Svatos, PhD.         Sokolovska 855/225 -/
/- Data Analyst,            Prague 9           -/
/- Eurotel Praha            190 00             -/
/- jan_svatos at eurotel.cz    Czechia            -/
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```