Re: [R] sub-matrix block size

From: Peter Alspach <>
Date: Wed, 27 Apr 2011 15:00:36 +1200

Tena koe Santosh

It is not clear to me precisely what your blocking rules are (e.g., where should matrix[4,4] go, is matrix[5:7,5:7] to be considered as a different block to matrix[8:10,8:10]). Also, what happens if there is an isolated 1 (e.g., in location matrix[9,6])? However, I imagine something could be achieved with judicious use of diag() and rle().

HTH .... Peter Alspach

> -----Original Message-----
> From: [mailto:r-help-bounces_at_r-
>] On Behalf Of Santosh
> Sent: Wednesday, 27 April 2011 12:14 p.m.
> To: r-help
> Subject: [R] sub-matrix block size
> Dear Rxperts
> Below is a small vector of values of zeros and non-zeros... was
> wondering if
> there is an efficient way to get the block sizes of submatrices of a
> big
> matrix similar to the one shown below? diagonal elements can be zero
> too.
> Rows with only a diagonal element may be considered as a unit block
> size.
> c(1,0,0,0,0,0,0,0,0,0,0,
> 1,1,0,0,0,0,0,0,0,0,0,
> 0,0,1,0,0,0,0,0,0,0,0,
> 0,0,0,0,0,0,0,0,0,0,0,
> 0,0,0,0,1,0,0,0,0,0,0,
> 0,0,0,0,1,1,0,0,0,0,0,
> 0,0,0,0,1,1,1,0,0,0,0,
> 0,0,0,0,0,0,0,1,0,0,0,
> 0,0,0,0,0,0,0,1,1,0,0,
> 0,0,0,0,0,0,0,1,1,1,0,
> 0,0,0,0,0,0,0,0,0,0,0)
> Thanks much!
> Santosh
> [[alternative HTML version deleted]]
> ______________________________________________
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> PLEASE do read the posting guide
> guide.html
> and provide commented, minimal, self-contained, reproducible code.

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