[R] Problems dealing with matrices

[Jeff Newmiller]

I think the following is a pretty literal translation from your 
description. Looks like a linear difference equation with a ramp forcing 
function.

wt <- matrix( c(1,0,0,0,0 ), nrow=5 )
vol <- matrix( NA, nrow=5, ncol=length( volinp ) )
vol[ , 1 ] <- dcmat %*% ( volmat + wt )

for ( idx in volinp[ -1 ] ) {
   vol[ , idx ] <- dcmat %*% ( vol[ , idx-1 ] + idx * wt )
}

On Sun, 24 Nov 2013, halim10-fes wrote:

>
> Please apologize me! Earlier I've sent a message erroneously. Following is the
> original problem for which I'm seeking help. Extremely sorry...
>
>
> Hi Arun,
>
> Thank you very much for your response. Sorry, if I couldn't explain clearly. I
> think, I should restate the problem to get exactly what I want. Here it goes:
>
> I have 2 matrices and 1 vector, namely,
>
> dcmat<-matrix(c(0.13,0.61,0.25,0.00,0.00,0.00,0.52,0.37,0.09,0.00,0.00,0.00,
>                0.58,0.30,0.11,0.00,0.00,0.00,0.46,0.22,0.00,0.00,0.00,0.00,
>                0.09),nrow=5,ncol=5)
>
> volmat<-matrix(c(100,0,0,0,0),nrow=5,ncol=1)
>
> volinp<-c(1:40)
>
> What I essentially want to do is to multiply 'dcmat' with 'volmat' and dump
> the output in a new matrix 'vol'. But before that, in the first step, I want
> to add volinp[1] with volmat[1,1]. So, the first column of the output matrix
> 'vol' matrix will be:
>
>        [,1]
> [1,]   13.13
> [2,]   61.61
> [3,]   25.25
> [4,]    0.00
> [5,]    0.00
>
> In the 2nd step, I want to replace 'volmat' with vol[,1] and add volinp[2]
> with vol[1,1]. The new 'volmat' will look like:
>
>        [,1]
> [1,]   15.13
> [2,]   61.61
> [3,]   25.25
> [4,]    0.00
> [5,]    0.00
>
> Then multiply 'dcmat' with the new 'volmat', and the 2nd column of output
> matrix 'vol' will look like:
>
>        [,2]
> [1,]  1.9669
> [2,] 41.2665
> [3,] 41.2232
> [4,] 13.1199
> [5,]  2.7775
>
> Then again, replace the 'volmat' with vol[,2], add volinp[3] with vol[1,2] and
> multiply the new 'volmat' with 'dcmat'. This replacement, addition,
> multiplication, and dumping will continue up to the length of 'volinp' and the
> final output matrix 'vol' will be something like:
>
>      [,1]    [,2]      [,3]    ...length(volinp)
> [1,] 13.13   1.9669   0.645697  ...
> [2,] 61.61  41.2665  24.488389  ...
> [3,] 25.25  41.2232  40.419786  ...
> [4,]  0.00  13.1199  22.116099  ...
> [5,]  0.00   2.7775   7.670905  ...
>
> Within my limited capacity, I've tried to come up with a solution but failed.
>
> I'll appreciate your/others' help with gratefulness.
>
> Regards,
>
> Halim
>
> ---------------
> Md. Abdul Halim
> Assistant Professor
> Department of Forestry and Environmental Science
> Shahjalal University of Science and Technology,Sylhet-3114,
> Bangladesh.
> Cell: +8801714078386.
> alt. e-mail: xou03 at yahoo.com
>
> On Sat, 23 Nov 2013 14:10:12 -0800 (PST), arun wrote
>> Hi,
>> Could you show your expected output?  It is a bit unclear from the
> description.
>>
>> On Saturday, November 23, 2013 2:00 PM, halim10-fes <halim10-
>> fes at sust.edu> wrote: Dear R-friends,
>>
>> Hope you doing well. I've been trying to deal with the following
>> problem for the couple of days but couldn't come up with a solution.
>> It would be great if any of you could give some insight into it.
>>
>> I have three matrices like:
>>
>> dcvol<-matrix(c(0.13,0.61,0.25,0.00,0.00,0.00,0.52,0.37,0.09,0.00,
>> 0.00,0.00,                 0.58,0.30,0.11,0.00,0.00,0.00,0.46,0.22,
>> 0.00,0.00,0.00,0.00,                 0.09),nrow=5,ncol=5)
> volinp<-
>> matrix(c(100,0,0,0,0),nrow=5,ncol=1)
>>
>> scvol<-matrix(c(1:40),nrow=5,ncol=8)
>>
>> What I essentially want to do is to add each value in scvol[1,] with
>> the volinp[1,1] and then multiply each new volinp with dcvol and
>> finally put the outputs in a new matrix.
>>
>> Thanks in advance.
>>
>> Halim               
>> ---------------
>> Md. Abdul Halim
>> Assistant Professor
>> Department of Forestry and Environmental Science
>> Shahjalal University of Science and Technology,Sylhet-3114,
>> Bangladesh.
>> Cell: +8801714078386.
>> alt. e-mail: xou03 at yahoo.com
>>
>> --
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>>
>> ______________________________________________
>> 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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>
> ______________________________________________
> 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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