# [R] A matrix automation problem

markleeds at verizon.net markleeds at verizon.net
Thu Oct 23 06:31:10 CEST 2008

```megh: assuming that i understand what you want, i think below does it
but check it carefully because i didn't.

i = 1:9
a = matrix(1:9, 3)

tempa <- lapply(i,function(.index) {
a^.index
})

tempb <- lapply(seq(1,dim(a)[1]*dim(a)[2],by=dim(a)[1]),function(.index)
{
do.call(rbind,tempa[.index:(.index+(dim(a)[1])-1)])
})

tempc <- do.call(cbind,tempb)
print(tempc)
print(str(tempc))

On Wed, Oct 22, 2008 at 11:57 PM, megh wrote:

> Thanks for your reply. Your solution is ok for this particular
> definition of
> bi = a * i
> . However I was looking for more general solution, like :
> bi = a *a*a*....(i-times)
>
> Is there any better idea?
> Thanks and regards,
>
>
> Greg Snow-2 wrote:
>>
>> Does this help point you in a useful direction?
>>
>>> a <- matrix(1:9, 3) * 10
>>> b <- matrix(1:9, 3)
>>> kronecker(b,a)
>>
>>
>>
>> --
>> Gregory (Greg) L. Snow Ph.D.
>> Statistical Data Center
>> Intermountain Healthcare
>> greg.snow at imail.org
>> 801.408.8111
>>
>>
>>> -----Original Message-----
>>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
>>> project.org] On Behalf Of megh
>>> Sent: Wednesday, October 22, 2008 3:22 AM
>>> To: r-help at r-project.org
>>> Subject: [R] A matrix automation problem
>>>
>>>
>>> [I am really sorry if it is double posted, I doubt me previous post
>>> could not
>>> reach forum due to some problem with net]
>>>
>>> Suppose I have a matrix :
>>>
>>> a = matrix(1:9, 3)
>>>
>>>> From this matrix, I construct 9 additional matrices :
>>>
>>> i = 1:9
>>> bi = a * i
>>>
>>> Now combining all those 9 new matrices, I construct a final metrix
>>> as :
>>>
>>> c =
>>>
>>> b1 b4 b7
>>> b2 b5 b8
>>> b3 b6 b8
>>>
>>> I want to automate this procedure for any arbitrary number "i"
>>>
>>> Can anyone please help me how to do that?
>>>
>>> Rgd,
>>>
>>>
>>> --
>>> View this message in context: http://www.nabble.com/A-matrix-
>>> automation-problem-tp20106932p20106932.html
>>> Sent from the R help mailing list archive at Nabble.com.
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide http://www.R-project.org/posting-
>>> guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
>
> --
> View this message in context:
> http://www.nabble.com/A-matrix-automation-problem-tp20106932p20123993.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

```

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