On 6/29/2006 7:38 AM, Sundar Dorai-Raj wrote:
>
> przeszczepan wrote:
>> Hi,
>>
>> I have got problems integrating the following function using "integrate":
>>
>> lambdat<-function(t){
>> tempT<-T[k,][!is.na(T[k,])]#available values from k-th row of matrix T
>> tempJ<-J[k,][!is.na(J[k,])]
>>
>> hg<-length(tempT[tempT<=t & tempJ==0])#counts observations satisfing the
>> conditions
>> ag<-length(tempT[tempT<=t & tempJ==1])
>>
>> lambdaXY[hg+1,ag+1]#takes values from a 10x10 matrix
>> }
>>
>> I keep receiving this message:
>>
>> 1: longer object length
>> is not a multiple of shorter object length in: tempT <= t
>> 2: longer object length
>> is not a multiple of shorter object length in: tempT <= t & tempJ ==
>> 0
>>
>> What I suspect is that the "integrate" function submits the whole vector of
>> points at which the integral is to be evaluated at once. For my function to
>> be integrated it would rather have to be evaluated at each point after
>> another in a loop of some kind.
>>
>
> You suspect correctly. Best to read ?integrate too.
>
>> Can you think of a way to solve this problem without me having to write the
>> integrating procedure from scratch (I have no idea about FORTRAN and this is
>> what the "integrate" description refers to)?
>>
>
> Just put a "for"-loop in your function to iterate over t.
Or use Vectorize().
vlambdat <- Vectorize(lambdat)
should give a function that can be passed to integrate(), assuming that
lambdat works when given a length 1 vector as input.
Duncan Murdoch
>
> n <- length(t)
> hg <- ag <- vector("numeric", n)
> for(i in seq(n)) {
> hg[i] <- length(tempT[tempT <= t[i] & tempJ == 0])
> ag[i] <- length(tempT[tempT <= t[i] & tempJ == 1])
> }
>
> I doubt this will work because integrate is expecting a vector of
> n=length(t) from lambdat. The last line of the function returns a nxn
> matrix. Please submit data to run the function plus your call to
> integrate in any subsequent postings.
>
> HTH,
>
> --sundar
>
>> Thank you.
>>
>> Kind Regards,
>> Lukasz Szczepanski
>> Student
>>
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>
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