[R] sub-matrix block size

Peter Alspach Peter.Alspach at plantandfood.co.nz
Wed Apr 27 05:00:36 CEST 2011

```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: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] 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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